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457c8996 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
1da177e4 LT |
2 | /* |
3 | * linux/kernel/fork.c | |
4 | * | |
5 | * Copyright (C) 1991, 1992 Linus Torvalds | |
6 | */ | |
7 | ||
8 | /* | |
9 | * 'fork.c' contains the help-routines for the 'fork' system call | |
10 | * (see also entry.S and others). | |
11 | * Fork is rather simple, once you get the hang of it, but the memory | |
12 | * management can be a bitch. See 'mm/memory.c': 'copy_page_range()' | |
13 | */ | |
14 | ||
b3e58382 | 15 | #include <linux/anon_inodes.h> |
1da177e4 | 16 | #include <linux/slab.h> |
4eb5aaa3 | 17 | #include <linux/sched/autogroup.h> |
6e84f315 | 18 | #include <linux/sched/mm.h> |
f7ccbae4 | 19 | #include <linux/sched/coredump.h> |
8703e8a4 | 20 | #include <linux/sched/user.h> |
6a3827d7 | 21 | #include <linux/sched/numa_balancing.h> |
03441a34 | 22 | #include <linux/sched/stat.h> |
29930025 | 23 | #include <linux/sched/task.h> |
68db0cf1 | 24 | #include <linux/sched/task_stack.h> |
32ef5517 | 25 | #include <linux/sched/cputime.h> |
b3e58382 | 26 | #include <linux/seq_file.h> |
037741a6 | 27 | #include <linux/rtmutex.h> |
1da177e4 LT |
28 | #include <linux/init.h> |
29 | #include <linux/unistd.h> | |
1da177e4 LT |
30 | #include <linux/module.h> |
31 | #include <linux/vmalloc.h> | |
32 | #include <linux/completion.h> | |
1da177e4 LT |
33 | #include <linux/personality.h> |
34 | #include <linux/mempolicy.h> | |
35 | #include <linux/sem.h> | |
36 | #include <linux/file.h> | |
9f3acc31 | 37 | #include <linux/fdtable.h> |
da9cbc87 | 38 | #include <linux/iocontext.h> |
1da177e4 LT |
39 | #include <linux/key.h> |
40 | #include <linux/binfmts.h> | |
41 | #include <linux/mman.h> | |
cddb8a5c | 42 | #include <linux/mmu_notifier.h> |
1da177e4 | 43 | #include <linux/fs.h> |
615d6e87 | 44 | #include <linux/mm.h> |
17fca131 | 45 | #include <linux/mm_inline.h> |
615d6e87 | 46 | #include <linux/vmacache.h> |
ab516013 | 47 | #include <linux/nsproxy.h> |
c59ede7b | 48 | #include <linux/capability.h> |
1da177e4 | 49 | #include <linux/cpu.h> |
b4f48b63 | 50 | #include <linux/cgroup.h> |
1da177e4 | 51 | #include <linux/security.h> |
a1e78772 | 52 | #include <linux/hugetlb.h> |
e2cfabdf | 53 | #include <linux/seccomp.h> |
1da177e4 LT |
54 | #include <linux/swap.h> |
55 | #include <linux/syscalls.h> | |
56 | #include <linux/jiffies.h> | |
57 | #include <linux/futex.h> | |
8141c7f3 | 58 | #include <linux/compat.h> |
207205a2 | 59 | #include <linux/kthread.h> |
7c3ab738 | 60 | #include <linux/task_io_accounting_ops.h> |
ab2af1f5 | 61 | #include <linux/rcupdate.h> |
1da177e4 LT |
62 | #include <linux/ptrace.h> |
63 | #include <linux/mount.h> | |
64 | #include <linux/audit.h> | |
78fb7466 | 65 | #include <linux/memcontrol.h> |
f201ae23 | 66 | #include <linux/ftrace.h> |
5e2bf014 | 67 | #include <linux/proc_fs.h> |
1da177e4 LT |
68 | #include <linux/profile.h> |
69 | #include <linux/rmap.h> | |
f8af4da3 | 70 | #include <linux/ksm.h> |
1da177e4 | 71 | #include <linux/acct.h> |
893e26e6 | 72 | #include <linux/userfaultfd_k.h> |
8f0ab514 | 73 | #include <linux/tsacct_kern.h> |
9f46080c | 74 | #include <linux/cn_proc.h> |
ba96a0c8 | 75 | #include <linux/freezer.h> |
ca74e92b | 76 | #include <linux/delayacct.h> |
ad4ecbcb | 77 | #include <linux/taskstats_kern.h> |
0a425405 | 78 | #include <linux/random.h> |
522ed776 | 79 | #include <linux/tty.h> |
5ad4e53b | 80 | #include <linux/fs_struct.h> |
7c9f8861 | 81 | #include <linux/magic.h> |
cdd6c482 | 82 | #include <linux/perf_event.h> |
42c4ab41 | 83 | #include <linux/posix-timers.h> |
8e7cac79 | 84 | #include <linux/user-return-notifier.h> |
3d5992d2 | 85 | #include <linux/oom.h> |
ba76149f | 86 | #include <linux/khugepaged.h> |
d80e731e | 87 | #include <linux/signalfd.h> |
0326f5a9 | 88 | #include <linux/uprobes.h> |
a27bb332 | 89 | #include <linux/aio.h> |
52f5684c | 90 | #include <linux/compiler.h> |
16db3d3f | 91 | #include <linux/sysctl.h> |
5c9a8750 | 92 | #include <linux/kcov.h> |
d83a7cb3 | 93 | #include <linux/livepatch.h> |
48ac3c18 | 94 | #include <linux/thread_info.h> |
afaef01c | 95 | #include <linux/stackleak.h> |
eafb149e | 96 | #include <linux/kasan.h> |
d08b9f0c | 97 | #include <linux/scs.h> |
0f212204 | 98 | #include <linux/io_uring.h> |
a10787e6 | 99 | #include <linux/bpf.h> |
1da177e4 | 100 | |
1da177e4 | 101 | #include <asm/pgalloc.h> |
7c0f6ba6 | 102 | #include <linux/uaccess.h> |
1da177e4 LT |
103 | #include <asm/mmu_context.h> |
104 | #include <asm/cacheflush.h> | |
105 | #include <asm/tlbflush.h> | |
106 | ||
ad8d75ff SR |
107 | #include <trace/events/sched.h> |
108 | ||
43d2b113 KH |
109 | #define CREATE_TRACE_POINTS |
110 | #include <trace/events/task.h> | |
111 | ||
ac1b398d HS |
112 | /* |
113 | * Minimum number of threads to boot the kernel | |
114 | */ | |
115 | #define MIN_THREADS 20 | |
116 | ||
117 | /* | |
118 | * Maximum number of threads | |
119 | */ | |
120 | #define MAX_THREADS FUTEX_TID_MASK | |
121 | ||
1da177e4 LT |
122 | /* |
123 | * Protected counters by write_lock_irq(&tasklist_lock) | |
124 | */ | |
125 | unsigned long total_forks; /* Handle normal Linux uptimes. */ | |
fb0a685c | 126 | int nr_threads; /* The idle threads do not count.. */ |
1da177e4 | 127 | |
8856ae4d | 128 | static int max_threads; /* tunable limit on nr_threads */ |
1da177e4 | 129 | |
8495f7e6 SPP |
130 | #define NAMED_ARRAY_INDEX(x) [x] = __stringify(x) |
131 | ||
132 | static const char * const resident_page_types[] = { | |
133 | NAMED_ARRAY_INDEX(MM_FILEPAGES), | |
134 | NAMED_ARRAY_INDEX(MM_ANONPAGES), | |
135 | NAMED_ARRAY_INDEX(MM_SWAPENTS), | |
136 | NAMED_ARRAY_INDEX(MM_SHMEMPAGES), | |
137 | }; | |
138 | ||
1da177e4 LT |
139 | DEFINE_PER_CPU(unsigned long, process_counts) = 0; |
140 | ||
c59923a1 | 141 | __cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */ |
db1466b3 PM |
142 | |
143 | #ifdef CONFIG_PROVE_RCU | |
144 | int lockdep_tasklist_lock_is_held(void) | |
145 | { | |
146 | return lockdep_is_held(&tasklist_lock); | |
147 | } | |
148 | EXPORT_SYMBOL_GPL(lockdep_tasklist_lock_is_held); | |
149 | #endif /* #ifdef CONFIG_PROVE_RCU */ | |
1da177e4 LT |
150 | |
151 | int nr_processes(void) | |
152 | { | |
153 | int cpu; | |
154 | int total = 0; | |
155 | ||
1d510750 | 156 | for_each_possible_cpu(cpu) |
1da177e4 LT |
157 | total += per_cpu(process_counts, cpu); |
158 | ||
159 | return total; | |
160 | } | |
161 | ||
f19b9f74 AM |
162 | void __weak arch_release_task_struct(struct task_struct *tsk) |
163 | { | |
164 | } | |
165 | ||
f5e10287 | 166 | #ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR |
e18b890b | 167 | static struct kmem_cache *task_struct_cachep; |
41101809 TG |
168 | |
169 | static inline struct task_struct *alloc_task_struct_node(int node) | |
170 | { | |
171 | return kmem_cache_alloc_node(task_struct_cachep, GFP_KERNEL, node); | |
172 | } | |
173 | ||
41101809 TG |
174 | static inline void free_task_struct(struct task_struct *tsk) |
175 | { | |
41101809 TG |
176 | kmem_cache_free(task_struct_cachep, tsk); |
177 | } | |
1da177e4 LT |
178 | #endif |
179 | ||
b235beea | 180 | #ifndef CONFIG_ARCH_THREAD_STACK_ALLOCATOR |
41101809 | 181 | |
0d15d74a TG |
182 | /* |
183 | * Allocate pages if THREAD_SIZE is >= PAGE_SIZE, otherwise use a | |
184 | * kmemcache based allocator. | |
185 | */ | |
ba14a194 | 186 | # if THREAD_SIZE >= PAGE_SIZE || defined(CONFIG_VMAP_STACK) |
ac496bf4 AL |
187 | |
188 | #ifdef CONFIG_VMAP_STACK | |
189 | /* | |
190 | * vmalloc() is a bit slow, and calling vfree() enough times will force a TLB | |
191 | * flush. Try to minimize the number of calls by caching stacks. | |
192 | */ | |
193 | #define NR_CACHED_STACKS 2 | |
194 | static DEFINE_PER_CPU(struct vm_struct *, cached_stacks[NR_CACHED_STACKS]); | |
19659c59 HR |
195 | |
196 | static int free_vm_stack_cache(unsigned int cpu) | |
197 | { | |
198 | struct vm_struct **cached_vm_stacks = per_cpu_ptr(cached_stacks, cpu); | |
199 | int i; | |
200 | ||
201 | for (i = 0; i < NR_CACHED_STACKS; i++) { | |
202 | struct vm_struct *vm_stack = cached_vm_stacks[i]; | |
203 | ||
204 | if (!vm_stack) | |
205 | continue; | |
206 | ||
207 | vfree(vm_stack->addr); | |
208 | cached_vm_stacks[i] = NULL; | |
209 | } | |
210 | ||
211 | return 0; | |
212 | } | |
ac496bf4 AL |
213 | #endif |
214 | ||
ba14a194 | 215 | static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node) |
b69c49b7 | 216 | { |
ba14a194 | 217 | #ifdef CONFIG_VMAP_STACK |
ac496bf4 AL |
218 | void *stack; |
219 | int i; | |
220 | ||
ac496bf4 | 221 | for (i = 0; i < NR_CACHED_STACKS; i++) { |
112166f8 CL |
222 | struct vm_struct *s; |
223 | ||
224 | s = this_cpu_xchg(cached_stacks[i], NULL); | |
ac496bf4 AL |
225 | |
226 | if (!s) | |
227 | continue; | |
ac496bf4 | 228 | |
cebd0eb2 AK |
229 | /* Mark stack accessible for KASAN. */ |
230 | kasan_unpoison_range(s->addr, THREAD_SIZE); | |
eafb149e | 231 | |
ca182551 KK |
232 | /* Clear stale pointers from reused stack. */ |
233 | memset(s->addr, 0, THREAD_SIZE); | |
e01e8063 | 234 | |
ac496bf4 | 235 | tsk->stack_vm_area = s; |
ba4a4574 | 236 | tsk->stack = s->addr; |
ac496bf4 AL |
237 | return s->addr; |
238 | } | |
ac496bf4 | 239 | |
9b6f7e16 RG |
240 | /* |
241 | * Allocated stacks are cached and later reused by new threads, | |
242 | * so memcg accounting is performed manually on assigning/releasing | |
243 | * stacks to tasks. Drop __GFP_ACCOUNT. | |
244 | */ | |
48ac3c18 | 245 | stack = __vmalloc_node_range(THREAD_SIZE, THREAD_ALIGN, |
ac496bf4 | 246 | VMALLOC_START, VMALLOC_END, |
9b6f7e16 | 247 | THREADINFO_GFP & ~__GFP_ACCOUNT, |
ac496bf4 AL |
248 | PAGE_KERNEL, |
249 | 0, node, __builtin_return_address(0)); | |
ba14a194 AL |
250 | |
251 | /* | |
252 | * We can't call find_vm_area() in interrupt context, and | |
253 | * free_thread_stack() can be called in interrupt context, | |
254 | * so cache the vm_struct. | |
255 | */ | |
5eed6f1d | 256 | if (stack) { |
ba14a194 | 257 | tsk->stack_vm_area = find_vm_area(stack); |
5eed6f1d RR |
258 | tsk->stack = stack; |
259 | } | |
ba14a194 AL |
260 | return stack; |
261 | #else | |
4949148a VD |
262 | struct page *page = alloc_pages_node(node, THREADINFO_GFP, |
263 | THREAD_SIZE_ORDER); | |
b6a84016 | 264 | |
1bf4580e | 265 | if (likely(page)) { |
8dcc1d34 | 266 | tsk->stack = kasan_reset_tag(page_address(page)); |
1bf4580e AA |
267 | return tsk->stack; |
268 | } | |
269 | return NULL; | |
ba14a194 | 270 | #endif |
b69c49b7 FT |
271 | } |
272 | ||
ba14a194 | 273 | static inline void free_thread_stack(struct task_struct *tsk) |
b69c49b7 | 274 | { |
ac496bf4 | 275 | #ifdef CONFIG_VMAP_STACK |
9b6f7e16 RG |
276 | struct vm_struct *vm = task_stack_vm_area(tsk); |
277 | ||
278 | if (vm) { | |
ac496bf4 AL |
279 | int i; |
280 | ||
991e7673 | 281 | for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++) |
f4b00eab | 282 | memcg_kmem_uncharge_page(vm->pages[i], 0); |
9b6f7e16 | 283 | |
ac496bf4 | 284 | for (i = 0; i < NR_CACHED_STACKS; i++) { |
112166f8 CL |
285 | if (this_cpu_cmpxchg(cached_stacks[i], |
286 | NULL, tsk->stack_vm_area) != NULL) | |
ac496bf4 AL |
287 | continue; |
288 | ||
ac496bf4 AL |
289 | return; |
290 | } | |
ac496bf4 | 291 | |
0f110a9b | 292 | vfree_atomic(tsk->stack); |
ac496bf4 AL |
293 | return; |
294 | } | |
295 | #endif | |
296 | ||
297 | __free_pages(virt_to_page(tsk->stack), THREAD_SIZE_ORDER); | |
b69c49b7 | 298 | } |
0d15d74a | 299 | # else |
b235beea | 300 | static struct kmem_cache *thread_stack_cache; |
0d15d74a | 301 | |
9521d399 | 302 | static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, |
0d15d74a TG |
303 | int node) |
304 | { | |
5eed6f1d RR |
305 | unsigned long *stack; |
306 | stack = kmem_cache_alloc_node(thread_stack_cache, THREADINFO_GFP, node); | |
8dcc1d34 | 307 | stack = kasan_reset_tag(stack); |
5eed6f1d RR |
308 | tsk->stack = stack; |
309 | return stack; | |
0d15d74a TG |
310 | } |
311 | ||
ba14a194 | 312 | static void free_thread_stack(struct task_struct *tsk) |
0d15d74a | 313 | { |
ba14a194 | 314 | kmem_cache_free(thread_stack_cache, tsk->stack); |
0d15d74a TG |
315 | } |
316 | ||
b235beea | 317 | void thread_stack_cache_init(void) |
0d15d74a | 318 | { |
f9d29946 DW |
319 | thread_stack_cache = kmem_cache_create_usercopy("thread_stack", |
320 | THREAD_SIZE, THREAD_SIZE, 0, 0, | |
321 | THREAD_SIZE, NULL); | |
b235beea | 322 | BUG_ON(thread_stack_cache == NULL); |
0d15d74a TG |
323 | } |
324 | # endif | |
b69c49b7 FT |
325 | #endif |
326 | ||
1da177e4 | 327 | /* SLAB cache for signal_struct structures (tsk->signal) */ |
e18b890b | 328 | static struct kmem_cache *signal_cachep; |
1da177e4 LT |
329 | |
330 | /* SLAB cache for sighand_struct structures (tsk->sighand) */ | |
e18b890b | 331 | struct kmem_cache *sighand_cachep; |
1da177e4 LT |
332 | |
333 | /* SLAB cache for files_struct structures (tsk->files) */ | |
e18b890b | 334 | struct kmem_cache *files_cachep; |
1da177e4 LT |
335 | |
336 | /* SLAB cache for fs_struct structures (tsk->fs) */ | |
e18b890b | 337 | struct kmem_cache *fs_cachep; |
1da177e4 LT |
338 | |
339 | /* SLAB cache for vm_area_struct structures */ | |
3928d4f5 | 340 | static struct kmem_cache *vm_area_cachep; |
1da177e4 LT |
341 | |
342 | /* SLAB cache for mm_struct structures (tsk->mm) */ | |
e18b890b | 343 | static struct kmem_cache *mm_cachep; |
1da177e4 | 344 | |
490fc053 | 345 | struct vm_area_struct *vm_area_alloc(struct mm_struct *mm) |
3928d4f5 | 346 | { |
a670468f | 347 | struct vm_area_struct *vma; |
490fc053 | 348 | |
a670468f | 349 | vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
027232da KS |
350 | if (vma) |
351 | vma_init(vma, mm); | |
490fc053 | 352 | return vma; |
3928d4f5 LT |
353 | } |
354 | ||
355 | struct vm_area_struct *vm_area_dup(struct vm_area_struct *orig) | |
356 | { | |
95faf699 LT |
357 | struct vm_area_struct *new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
358 | ||
359 | if (new) { | |
cda099b3 QC |
360 | ASSERT_EXCLUSIVE_WRITER(orig->vm_flags); |
361 | ASSERT_EXCLUSIVE_WRITER(orig->vm_file); | |
362 | /* | |
363 | * orig->shared.rb may be modified concurrently, but the clone | |
364 | * will be reinitialized. | |
365 | */ | |
366 | *new = data_race(*orig); | |
95faf699 | 367 | INIT_LIST_HEAD(&new->anon_vma_chain); |
e39a4b33 | 368 | new->vm_next = new->vm_prev = NULL; |
9a10064f | 369 | dup_vma_anon_name(orig, new); |
95faf699 LT |
370 | } |
371 | return new; | |
3928d4f5 LT |
372 | } |
373 | ||
374 | void vm_area_free(struct vm_area_struct *vma) | |
375 | { | |
9a10064f | 376 | free_vma_anon_name(vma); |
3928d4f5 LT |
377 | kmem_cache_free(vm_area_cachep, vma); |
378 | } | |
379 | ||
ba14a194 | 380 | static void account_kernel_stack(struct task_struct *tsk, int account) |
c6a7f572 | 381 | { |
ba14a194 AL |
382 | void *stack = task_stack_page(tsk); |
383 | struct vm_struct *vm = task_stack_vm_area(tsk); | |
384 | ||
27faca83 MS |
385 | if (vm) { |
386 | int i; | |
ba14a194 | 387 | |
27faca83 MS |
388 | for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++) |
389 | mod_lruvec_page_state(vm->pages[i], NR_KERNEL_STACK_KB, | |
390 | account * (PAGE_SIZE / 1024)); | |
391 | } else { | |
392 | /* All stack pages are in the same node. */ | |
da3ceeff | 393 | mod_lruvec_kmem_state(stack, NR_KERNEL_STACK_KB, |
991e7673 | 394 | account * (THREAD_SIZE / 1024)); |
27faca83 | 395 | } |
c6a7f572 KM |
396 | } |
397 | ||
9b6f7e16 RG |
398 | static int memcg_charge_kernel_stack(struct task_struct *tsk) |
399 | { | |
400 | #ifdef CONFIG_VMAP_STACK | |
401 | struct vm_struct *vm = task_stack_vm_area(tsk); | |
402 | int ret; | |
403 | ||
991e7673 SB |
404 | BUILD_BUG_ON(IS_ENABLED(CONFIG_VMAP_STACK) && PAGE_SIZE % 1024 != 0); |
405 | ||
9b6f7e16 RG |
406 | if (vm) { |
407 | int i; | |
408 | ||
991e7673 SB |
409 | BUG_ON(vm->nr_pages != THREAD_SIZE / PAGE_SIZE); |
410 | ||
9b6f7e16 RG |
411 | for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++) { |
412 | /* | |
bcfe06bf RG |
413 | * If memcg_kmem_charge_page() fails, page's |
414 | * memory cgroup pointer is NULL, and | |
415 | * memcg_kmem_uncharge_page() in free_thread_stack() | |
416 | * will ignore this page. | |
9b6f7e16 | 417 | */ |
f4b00eab RG |
418 | ret = memcg_kmem_charge_page(vm->pages[i], GFP_KERNEL, |
419 | 0); | |
9b6f7e16 RG |
420 | if (ret) |
421 | return ret; | |
9b6f7e16 RG |
422 | } |
423 | } | |
424 | #endif | |
425 | return 0; | |
426 | } | |
427 | ||
68f24b08 | 428 | static void release_task_stack(struct task_struct *tsk) |
1da177e4 | 429 | { |
2f064a59 | 430 | if (WARN_ON(READ_ONCE(tsk->__state) != TASK_DEAD)) |
405c0759 AL |
431 | return; /* Better to leak the stack than to free prematurely */ |
432 | ||
ba14a194 | 433 | account_kernel_stack(tsk, -1); |
ba14a194 | 434 | free_thread_stack(tsk); |
68f24b08 AL |
435 | tsk->stack = NULL; |
436 | #ifdef CONFIG_VMAP_STACK | |
437 | tsk->stack_vm_area = NULL; | |
438 | #endif | |
439 | } | |
440 | ||
441 | #ifdef CONFIG_THREAD_INFO_IN_TASK | |
442 | void put_task_stack(struct task_struct *tsk) | |
443 | { | |
f0b89d39 | 444 | if (refcount_dec_and_test(&tsk->stack_refcount)) |
68f24b08 AL |
445 | release_task_stack(tsk); |
446 | } | |
447 | #endif | |
448 | ||
449 | void free_task(struct task_struct *tsk) | |
450 | { | |
b90ca8ba | 451 | release_user_cpus_ptr(tsk); |
d08b9f0c ST |
452 | scs_release(tsk); |
453 | ||
68f24b08 AL |
454 | #ifndef CONFIG_THREAD_INFO_IN_TASK |
455 | /* | |
456 | * The task is finally done with both the stack and thread_info, | |
457 | * so free both. | |
458 | */ | |
459 | release_task_stack(tsk); | |
460 | #else | |
461 | /* | |
462 | * If the task had a separate stack allocation, it should be gone | |
463 | * by now. | |
464 | */ | |
f0b89d39 | 465 | WARN_ON_ONCE(refcount_read(&tsk->stack_refcount) != 0); |
68f24b08 | 466 | #endif |
23f78d4a | 467 | rt_mutex_debug_task_free(tsk); |
fb52607a | 468 | ftrace_graph_exit_task(tsk); |
f19b9f74 | 469 | arch_release_task_struct(tsk); |
1da5c46f ON |
470 | if (tsk->flags & PF_KTHREAD) |
471 | free_kthread_struct(tsk); | |
1da177e4 LT |
472 | free_task_struct(tsk); |
473 | } | |
474 | EXPORT_SYMBOL(free_task); | |
475 | ||
fe69d560 DH |
476 | static void dup_mm_exe_file(struct mm_struct *mm, struct mm_struct *oldmm) |
477 | { | |
478 | struct file *exe_file; | |
479 | ||
480 | exe_file = get_mm_exe_file(oldmm); | |
481 | RCU_INIT_POINTER(mm->exe_file, exe_file); | |
482 | /* | |
483 | * We depend on the oldmm having properly denied write access to the | |
484 | * exe_file already. | |
485 | */ | |
486 | if (exe_file && deny_write_access(exe_file)) | |
487 | pr_warn_once("deny_write_access() failed in %s\n", __func__); | |
488 | } | |
489 | ||
d70f2a14 AM |
490 | #ifdef CONFIG_MMU |
491 | static __latent_entropy int dup_mmap(struct mm_struct *mm, | |
492 | struct mm_struct *oldmm) | |
493 | { | |
494 | struct vm_area_struct *mpnt, *tmp, *prev, **pprev; | |
495 | struct rb_node **rb_link, *rb_parent; | |
496 | int retval; | |
497 | unsigned long charge; | |
498 | LIST_HEAD(uf); | |
499 | ||
500 | uprobe_start_dup_mmap(); | |
d8ed45c5 | 501 | if (mmap_write_lock_killable(oldmm)) { |
d70f2a14 AM |
502 | retval = -EINTR; |
503 | goto fail_uprobe_end; | |
504 | } | |
505 | flush_cache_dup_mm(oldmm); | |
506 | uprobe_dup_mmap(oldmm, mm); | |
507 | /* | |
508 | * Not linked in yet - no deadlock potential: | |
509 | */ | |
aaa2cc56 | 510 | mmap_write_lock_nested(mm, SINGLE_DEPTH_NESTING); |
d70f2a14 AM |
511 | |
512 | /* No ordering required: file already has been exposed. */ | |
fe69d560 | 513 | dup_mm_exe_file(mm, oldmm); |
d70f2a14 AM |
514 | |
515 | mm->total_vm = oldmm->total_vm; | |
516 | mm->data_vm = oldmm->data_vm; | |
517 | mm->exec_vm = oldmm->exec_vm; | |
518 | mm->stack_vm = oldmm->stack_vm; | |
519 | ||
520 | rb_link = &mm->mm_rb.rb_node; | |
521 | rb_parent = NULL; | |
522 | pprev = &mm->mmap; | |
523 | retval = ksm_fork(mm, oldmm); | |
524 | if (retval) | |
525 | goto out; | |
526 | retval = khugepaged_fork(mm, oldmm); | |
527 | if (retval) | |
528 | goto out; | |
529 | ||
530 | prev = NULL; | |
531 | for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) { | |
532 | struct file *file; | |
533 | ||
534 | if (mpnt->vm_flags & VM_DONTCOPY) { | |
535 | vm_stat_account(mm, mpnt->vm_flags, -vma_pages(mpnt)); | |
536 | continue; | |
537 | } | |
538 | charge = 0; | |
655c79bb TH |
539 | /* |
540 | * Don't duplicate many vmas if we've been oom-killed (for | |
541 | * example) | |
542 | */ | |
543 | if (fatal_signal_pending(current)) { | |
544 | retval = -EINTR; | |
545 | goto out; | |
546 | } | |
d70f2a14 AM |
547 | if (mpnt->vm_flags & VM_ACCOUNT) { |
548 | unsigned long len = vma_pages(mpnt); | |
549 | ||
550 | if (security_vm_enough_memory_mm(oldmm, len)) /* sic */ | |
551 | goto fail_nomem; | |
552 | charge = len; | |
553 | } | |
3928d4f5 | 554 | tmp = vm_area_dup(mpnt); |
d70f2a14 AM |
555 | if (!tmp) |
556 | goto fail_nomem; | |
d70f2a14 AM |
557 | retval = vma_dup_policy(mpnt, tmp); |
558 | if (retval) | |
559 | goto fail_nomem_policy; | |
560 | tmp->vm_mm = mm; | |
561 | retval = dup_userfaultfd(tmp, &uf); | |
562 | if (retval) | |
563 | goto fail_nomem_anon_vma_fork; | |
564 | if (tmp->vm_flags & VM_WIPEONFORK) { | |
93949bb2 LX |
565 | /* |
566 | * VM_WIPEONFORK gets a clean slate in the child. | |
567 | * Don't prepare anon_vma until fault since we don't | |
568 | * copy page for current vma. | |
569 | */ | |
d70f2a14 | 570 | tmp->anon_vma = NULL; |
d70f2a14 AM |
571 | } else if (anon_vma_fork(tmp, mpnt)) |
572 | goto fail_nomem_anon_vma_fork; | |
573 | tmp->vm_flags &= ~(VM_LOCKED | VM_LOCKONFAULT); | |
d70f2a14 AM |
574 | file = tmp->vm_file; |
575 | if (file) { | |
d70f2a14 AM |
576 | struct address_space *mapping = file->f_mapping; |
577 | ||
578 | get_file(file); | |
d70f2a14 AM |
579 | i_mmap_lock_write(mapping); |
580 | if (tmp->vm_flags & VM_SHARED) | |
cf508b58 | 581 | mapping_allow_writable(mapping); |
d70f2a14 AM |
582 | flush_dcache_mmap_lock(mapping); |
583 | /* insert tmp into the share list, just after mpnt */ | |
584 | vma_interval_tree_insert_after(tmp, mpnt, | |
585 | &mapping->i_mmap); | |
586 | flush_dcache_mmap_unlock(mapping); | |
587 | i_mmap_unlock_write(mapping); | |
588 | } | |
589 | ||
590 | /* | |
591 | * Clear hugetlb-related page reserves for children. This only | |
592 | * affects MAP_PRIVATE mappings. Faults generated by the child | |
593 | * are not guaranteed to succeed, even if read-only | |
594 | */ | |
595 | if (is_vm_hugetlb_page(tmp)) | |
596 | reset_vma_resv_huge_pages(tmp); | |
597 | ||
598 | /* | |
599 | * Link in the new vma and copy the page table entries. | |
600 | */ | |
601 | *pprev = tmp; | |
602 | pprev = &tmp->vm_next; | |
603 | tmp->vm_prev = prev; | |
604 | prev = tmp; | |
605 | ||
606 | __vma_link_rb(mm, tmp, rb_link, rb_parent); | |
607 | rb_link = &tmp->vm_rb.rb_right; | |
608 | rb_parent = &tmp->vm_rb; | |
609 | ||
610 | mm->map_count++; | |
611 | if (!(tmp->vm_flags & VM_WIPEONFORK)) | |
c78f4636 | 612 | retval = copy_page_range(tmp, mpnt); |
d70f2a14 AM |
613 | |
614 | if (tmp->vm_ops && tmp->vm_ops->open) | |
615 | tmp->vm_ops->open(tmp); | |
616 | ||
617 | if (retval) | |
618 | goto out; | |
619 | } | |
620 | /* a new mm has just been created */ | |
1ed0cc5a | 621 | retval = arch_dup_mmap(oldmm, mm); |
d70f2a14 | 622 | out: |
d8ed45c5 | 623 | mmap_write_unlock(mm); |
d70f2a14 | 624 | flush_tlb_mm(oldmm); |
d8ed45c5 | 625 | mmap_write_unlock(oldmm); |
d70f2a14 AM |
626 | dup_userfaultfd_complete(&uf); |
627 | fail_uprobe_end: | |
628 | uprobe_end_dup_mmap(); | |
629 | return retval; | |
630 | fail_nomem_anon_vma_fork: | |
631 | mpol_put(vma_policy(tmp)); | |
632 | fail_nomem_policy: | |
3928d4f5 | 633 | vm_area_free(tmp); |
d70f2a14 AM |
634 | fail_nomem: |
635 | retval = -ENOMEM; | |
636 | vm_unacct_memory(charge); | |
637 | goto out; | |
638 | } | |
639 | ||
640 | static inline int mm_alloc_pgd(struct mm_struct *mm) | |
641 | { | |
642 | mm->pgd = pgd_alloc(mm); | |
643 | if (unlikely(!mm->pgd)) | |
644 | return -ENOMEM; | |
645 | return 0; | |
646 | } | |
647 | ||
648 | static inline void mm_free_pgd(struct mm_struct *mm) | |
649 | { | |
650 | pgd_free(mm, mm->pgd); | |
651 | } | |
652 | #else | |
653 | static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) | |
654 | { | |
d8ed45c5 | 655 | mmap_write_lock(oldmm); |
fe69d560 | 656 | dup_mm_exe_file(mm, oldmm); |
d8ed45c5 | 657 | mmap_write_unlock(oldmm); |
d70f2a14 AM |
658 | return 0; |
659 | } | |
660 | #define mm_alloc_pgd(mm) (0) | |
661 | #define mm_free_pgd(mm) | |
662 | #endif /* CONFIG_MMU */ | |
663 | ||
664 | static void check_mm(struct mm_struct *mm) | |
665 | { | |
666 | int i; | |
667 | ||
8495f7e6 SPP |
668 | BUILD_BUG_ON_MSG(ARRAY_SIZE(resident_page_types) != NR_MM_COUNTERS, |
669 | "Please make sure 'struct resident_page_types[]' is updated as well"); | |
670 | ||
d70f2a14 AM |
671 | for (i = 0; i < NR_MM_COUNTERS; i++) { |
672 | long x = atomic_long_read(&mm->rss_stat.count[i]); | |
673 | ||
674 | if (unlikely(x)) | |
8495f7e6 SPP |
675 | pr_alert("BUG: Bad rss-counter state mm:%p type:%s val:%ld\n", |
676 | mm, resident_page_types[i], x); | |
d70f2a14 AM |
677 | } |
678 | ||
679 | if (mm_pgtables_bytes(mm)) | |
680 | pr_alert("BUG: non-zero pgtables_bytes on freeing mm: %ld\n", | |
681 | mm_pgtables_bytes(mm)); | |
682 | ||
683 | #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS | |
684 | VM_BUG_ON_MM(mm->pmd_huge_pte, mm); | |
685 | #endif | |
686 | } | |
687 | ||
688 | #define allocate_mm() (kmem_cache_alloc(mm_cachep, GFP_KERNEL)) | |
689 | #define free_mm(mm) (kmem_cache_free(mm_cachep, (mm))) | |
690 | ||
691 | /* | |
692 | * Called when the last reference to the mm | |
693 | * is dropped: either by a lazy thread or by | |
694 | * mmput. Free the page directory and the mm. | |
695 | */ | |
d34bc48f | 696 | void __mmdrop(struct mm_struct *mm) |
d70f2a14 AM |
697 | { |
698 | BUG_ON(mm == &init_mm); | |
3eda69c9 MR |
699 | WARN_ON_ONCE(mm == current->mm); |
700 | WARN_ON_ONCE(mm == current->active_mm); | |
d70f2a14 AM |
701 | mm_free_pgd(mm); |
702 | destroy_context(mm); | |
984cfe4e | 703 | mmu_notifier_subscriptions_destroy(mm); |
d70f2a14 AM |
704 | check_mm(mm); |
705 | put_user_ns(mm->user_ns); | |
706 | free_mm(mm); | |
707 | } | |
d34bc48f | 708 | EXPORT_SYMBOL_GPL(__mmdrop); |
d70f2a14 AM |
709 | |
710 | static void mmdrop_async_fn(struct work_struct *work) | |
711 | { | |
712 | struct mm_struct *mm; | |
713 | ||
714 | mm = container_of(work, struct mm_struct, async_put_work); | |
715 | __mmdrop(mm); | |
716 | } | |
717 | ||
718 | static void mmdrop_async(struct mm_struct *mm) | |
719 | { | |
720 | if (unlikely(atomic_dec_and_test(&mm->mm_count))) { | |
721 | INIT_WORK(&mm->async_put_work, mmdrop_async_fn); | |
722 | schedule_work(&mm->async_put_work); | |
723 | } | |
724 | } | |
725 | ||
ea6d290c ON |
726 | static inline void free_signal_struct(struct signal_struct *sig) |
727 | { | |
97101eb4 | 728 | taskstats_tgid_free(sig); |
1c5354de | 729 | sched_autogroup_exit(sig); |
7283094e MH |
730 | /* |
731 | * __mmdrop is not safe to call from softirq context on x86 due to | |
732 | * pgd_dtor so postpone it to the async context | |
733 | */ | |
26db62f1 | 734 | if (sig->oom_mm) |
7283094e | 735 | mmdrop_async(sig->oom_mm); |
ea6d290c ON |
736 | kmem_cache_free(signal_cachep, sig); |
737 | } | |
738 | ||
739 | static inline void put_signal_struct(struct signal_struct *sig) | |
740 | { | |
60d4de3f | 741 | if (refcount_dec_and_test(&sig->sigcnt)) |
ea6d290c ON |
742 | free_signal_struct(sig); |
743 | } | |
744 | ||
158d9ebd | 745 | void __put_task_struct(struct task_struct *tsk) |
1da177e4 | 746 | { |
270f722d | 747 | WARN_ON(!tsk->exit_state); |
ec1d2819 | 748 | WARN_ON(refcount_read(&tsk->usage)); |
1da177e4 LT |
749 | WARN_ON(tsk == current); |
750 | ||
0f212204 | 751 | io_uring_free(tsk); |
2e91fa7f | 752 | cgroup_free(tsk); |
16d51a59 | 753 | task_numa_free(tsk, true); |
1a2a4d06 | 754 | security_task_free(tsk); |
a10787e6 | 755 | bpf_task_storage_free(tsk); |
e0e81739 | 756 | exit_creds(tsk); |
35df17c5 | 757 | delayacct_tsk_free(tsk); |
ea6d290c | 758 | put_signal_struct(tsk->signal); |
6e33cad0 | 759 | sched_core_free(tsk); |
2873cd31 | 760 | free_task(tsk); |
1da177e4 | 761 | } |
77c100c8 | 762 | EXPORT_SYMBOL_GPL(__put_task_struct); |
1da177e4 | 763 | |
6c0a9fa6 | 764 | void __init __weak arch_task_cache_init(void) { } |
61c4628b | 765 | |
ff691f6e HS |
766 | /* |
767 | * set_max_threads | |
768 | */ | |
16db3d3f | 769 | static void set_max_threads(unsigned int max_threads_suggested) |
ff691f6e | 770 | { |
ac1b398d | 771 | u64 threads; |
ca79b0c2 | 772 | unsigned long nr_pages = totalram_pages(); |
ff691f6e HS |
773 | |
774 | /* | |
ac1b398d HS |
775 | * The number of threads shall be limited such that the thread |
776 | * structures may only consume a small part of the available memory. | |
ff691f6e | 777 | */ |
3d6357de | 778 | if (fls64(nr_pages) + fls64(PAGE_SIZE) > 64) |
ac1b398d HS |
779 | threads = MAX_THREADS; |
780 | else | |
3d6357de | 781 | threads = div64_u64((u64) nr_pages * (u64) PAGE_SIZE, |
ac1b398d HS |
782 | (u64) THREAD_SIZE * 8UL); |
783 | ||
16db3d3f HS |
784 | if (threads > max_threads_suggested) |
785 | threads = max_threads_suggested; | |
786 | ||
ac1b398d | 787 | max_threads = clamp_t(u64, threads, MIN_THREADS, MAX_THREADS); |
ff691f6e HS |
788 | } |
789 | ||
5aaeb5c0 IM |
790 | #ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT |
791 | /* Initialized by the architecture: */ | |
792 | int arch_task_struct_size __read_mostly; | |
793 | #endif | |
0c8c0f03 | 794 | |
4189ff23 | 795 | #ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR |
5905429a KC |
796 | static void task_struct_whitelist(unsigned long *offset, unsigned long *size) |
797 | { | |
798 | /* Fetch thread_struct whitelist for the architecture. */ | |
799 | arch_thread_struct_whitelist(offset, size); | |
800 | ||
801 | /* | |
802 | * Handle zero-sized whitelist or empty thread_struct, otherwise | |
803 | * adjust offset to position of thread_struct in task_struct. | |
804 | */ | |
805 | if (unlikely(*size == 0)) | |
806 | *offset = 0; | |
807 | else | |
808 | *offset += offsetof(struct task_struct, thread); | |
809 | } | |
4189ff23 | 810 | #endif /* CONFIG_ARCH_TASK_STRUCT_ALLOCATOR */ |
5905429a | 811 | |
ff691f6e | 812 | void __init fork_init(void) |
1da177e4 | 813 | { |
25f9c081 | 814 | int i; |
f5e10287 | 815 | #ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR |
1da177e4 | 816 | #ifndef ARCH_MIN_TASKALIGN |
e274795e | 817 | #define ARCH_MIN_TASKALIGN 0 |
1da177e4 | 818 | #endif |
95cb64c1 | 819 | int align = max_t(int, L1_CACHE_BYTES, ARCH_MIN_TASKALIGN); |
5905429a | 820 | unsigned long useroffset, usersize; |
e274795e | 821 | |
1da177e4 | 822 | /* create a slab on which task_structs can be allocated */ |
5905429a KC |
823 | task_struct_whitelist(&useroffset, &usersize); |
824 | task_struct_cachep = kmem_cache_create_usercopy("task_struct", | |
e274795e | 825 | arch_task_struct_size, align, |
5905429a KC |
826 | SLAB_PANIC|SLAB_ACCOUNT, |
827 | useroffset, usersize, NULL); | |
1da177e4 LT |
828 | #endif |
829 | ||
61c4628b SS |
830 | /* do the arch specific task caches init */ |
831 | arch_task_cache_init(); | |
832 | ||
16db3d3f | 833 | set_max_threads(MAX_THREADS); |
1da177e4 LT |
834 | |
835 | init_task.signal->rlim[RLIMIT_NPROC].rlim_cur = max_threads/2; | |
836 | init_task.signal->rlim[RLIMIT_NPROC].rlim_max = max_threads/2; | |
837 | init_task.signal->rlim[RLIMIT_SIGPENDING] = | |
838 | init_task.signal->rlim[RLIMIT_NPROC]; | |
b376c3e1 | 839 | |
21d1c5e3 | 840 | for (i = 0; i < MAX_PER_NAMESPACE_UCOUNTS; i++) |
25f9c081 | 841 | init_user_ns.ucount_max[i] = max_threads/2; |
19659c59 | 842 | |
5ddf994f EB |
843 | set_rlimit_ucount_max(&init_user_ns, UCOUNT_RLIMIT_NPROC, RLIM_INFINITY); |
844 | set_rlimit_ucount_max(&init_user_ns, UCOUNT_RLIMIT_MSGQUEUE, RLIM_INFINITY); | |
845 | set_rlimit_ucount_max(&init_user_ns, UCOUNT_RLIMIT_SIGPENDING, RLIM_INFINITY); | |
846 | set_rlimit_ucount_max(&init_user_ns, UCOUNT_RLIMIT_MEMLOCK, RLIM_INFINITY); | |
21d1c5e3 | 847 | |
19659c59 HR |
848 | #ifdef CONFIG_VMAP_STACK |
849 | cpuhp_setup_state(CPUHP_BP_PREPARE_DYN, "fork:vm_stack_cache", | |
850 | NULL, free_vm_stack_cache); | |
851 | #endif | |
b09be676 | 852 | |
d08b9f0c ST |
853 | scs_init(); |
854 | ||
b09be676 | 855 | lockdep_init_task(&init_task); |
aad42dd4 | 856 | uprobes_init(); |
1da177e4 LT |
857 | } |
858 | ||
52f5684c | 859 | int __weak arch_dup_task_struct(struct task_struct *dst, |
61c4628b SS |
860 | struct task_struct *src) |
861 | { | |
862 | *dst = *src; | |
863 | return 0; | |
864 | } | |
865 | ||
d4311ff1 AT |
866 | void set_task_stack_end_magic(struct task_struct *tsk) |
867 | { | |
868 | unsigned long *stackend; | |
869 | ||
870 | stackend = end_of_stack(tsk); | |
871 | *stackend = STACK_END_MAGIC; /* for overflow detection */ | |
872 | } | |
873 | ||
725fc629 | 874 | static struct task_struct *dup_task_struct(struct task_struct *orig, int node) |
1da177e4 LT |
875 | { |
876 | struct task_struct *tsk; | |
b235beea | 877 | unsigned long *stack; |
0f4991e8 | 878 | struct vm_struct *stack_vm_area __maybe_unused; |
3e26c149 | 879 | int err; |
1da177e4 | 880 | |
725fc629 AK |
881 | if (node == NUMA_NO_NODE) |
882 | node = tsk_fork_get_node(orig); | |
504f52b5 | 883 | tsk = alloc_task_struct_node(node); |
1da177e4 LT |
884 | if (!tsk) |
885 | return NULL; | |
886 | ||
b235beea LT |
887 | stack = alloc_thread_stack_node(tsk, node); |
888 | if (!stack) | |
f19b9f74 | 889 | goto free_tsk; |
1da177e4 | 890 | |
9b6f7e16 RG |
891 | if (memcg_charge_kernel_stack(tsk)) |
892 | goto free_stack; | |
893 | ||
ba14a194 AL |
894 | stack_vm_area = task_stack_vm_area(tsk); |
895 | ||
fb0a685c | 896 | err = arch_dup_task_struct(tsk, orig); |
ba14a194 AL |
897 | |
898 | /* | |
899 | * arch_dup_task_struct() clobbers the stack-related fields. Make | |
900 | * sure they're properly initialized before using any stack-related | |
901 | * functions again. | |
902 | */ | |
903 | tsk->stack = stack; | |
904 | #ifdef CONFIG_VMAP_STACK | |
905 | tsk->stack_vm_area = stack_vm_area; | |
906 | #endif | |
68f24b08 | 907 | #ifdef CONFIG_THREAD_INFO_IN_TASK |
f0b89d39 | 908 | refcount_set(&tsk->stack_refcount, 1); |
68f24b08 | 909 | #endif |
ba14a194 | 910 | |
164c33c6 | 911 | if (err) |
b235beea | 912 | goto free_stack; |
164c33c6 | 913 | |
d08b9f0c ST |
914 | err = scs_prepare(tsk, node); |
915 | if (err) | |
916 | goto free_stack; | |
917 | ||
dbd95212 KC |
918 | #ifdef CONFIG_SECCOMP |
919 | /* | |
920 | * We must handle setting up seccomp filters once we're under | |
921 | * the sighand lock in case orig has changed between now and | |
922 | * then. Until then, filter must be NULL to avoid messing up | |
923 | * the usage counts on the error path calling free_task. | |
924 | */ | |
925 | tsk->seccomp.filter = NULL; | |
926 | #endif | |
87bec58a AM |
927 | |
928 | setup_thread_stack(tsk, orig); | |
8e7cac79 | 929 | clear_user_return_notifier(tsk); |
f26f9aff | 930 | clear_tsk_need_resched(tsk); |
d4311ff1 | 931 | set_task_stack_end_magic(tsk); |
1446e1df | 932 | clear_syscall_work_syscall_user_dispatch(tsk); |
1da177e4 | 933 | |
050e9baa | 934 | #ifdef CONFIG_STACKPROTECTOR |
7cd815bc | 935 | tsk->stack_canary = get_random_canary(); |
0a425405 | 936 | #endif |
3bd37062 SAS |
937 | if (orig->cpus_ptr == &orig->cpus_mask) |
938 | tsk->cpus_ptr = &tsk->cpus_mask; | |
b90ca8ba | 939 | dup_user_cpus_ptr(tsk, orig, node); |
0a425405 | 940 | |
fb0a685c | 941 | /* |
0ff7b2cf EB |
942 | * One for the user space visible state that goes away when reaped. |
943 | * One for the scheduler. | |
fb0a685c | 944 | */ |
0ff7b2cf EB |
945 | refcount_set(&tsk->rcu_users, 2); |
946 | /* One for the rcu users */ | |
947 | refcount_set(&tsk->usage, 1); | |
6c5c9341 | 948 | #ifdef CONFIG_BLK_DEV_IO_TRACE |
2056a782 | 949 | tsk->btrace_seq = 0; |
6c5c9341 | 950 | #endif |
a0aa7f68 | 951 | tsk->splice_pipe = NULL; |
5640f768 | 952 | tsk->task_frag.page = NULL; |
093e5840 | 953 | tsk->wake_q.next = NULL; |
e32cf5df | 954 | tsk->worker_private = NULL; |
c6a7f572 | 955 | |
ba14a194 | 956 | account_kernel_stack(tsk, 1); |
c6a7f572 | 957 | |
5c9a8750 | 958 | kcov_task_init(tsk); |
5fbda3ec | 959 | kmap_local_fork(tsk); |
5c9a8750 | 960 | |
e41d5818 DV |
961 | #ifdef CONFIG_FAULT_INJECTION |
962 | tsk->fail_nth = 0; | |
963 | #endif | |
964 | ||
2c323017 JB |
965 | #ifdef CONFIG_BLK_CGROUP |
966 | tsk->throttle_queue = NULL; | |
967 | tsk->use_memdelay = 0; | |
968 | #endif | |
969 | ||
d46eb14b SB |
970 | #ifdef CONFIG_MEMCG |
971 | tsk->active_memcg = NULL; | |
972 | #endif | |
1da177e4 | 973 | return tsk; |
61c4628b | 974 | |
b235beea | 975 | free_stack: |
ba14a194 | 976 | free_thread_stack(tsk); |
f19b9f74 | 977 | free_tsk: |
61c4628b SS |
978 | free_task_struct(tsk); |
979 | return NULL; | |
1da177e4 LT |
980 | } |
981 | ||
23ff4440 | 982 | __cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock); |
1da177e4 | 983 | |
4cb0e11b HK |
984 | static unsigned long default_dump_filter = MMF_DUMP_FILTER_DEFAULT; |
985 | ||
986 | static int __init coredump_filter_setup(char *s) | |
987 | { | |
988 | default_dump_filter = | |
989 | (simple_strtoul(s, NULL, 0) << MMF_DUMP_FILTER_SHIFT) & | |
990 | MMF_DUMP_FILTER_MASK; | |
991 | return 1; | |
992 | } | |
993 | ||
994 | __setup("coredump_filter=", coredump_filter_setup); | |
995 | ||
1da177e4 LT |
996 | #include <linux/init_task.h> |
997 | ||
858f0993 AD |
998 | static void mm_init_aio(struct mm_struct *mm) |
999 | { | |
1000 | #ifdef CONFIG_AIO | |
1001 | spin_lock_init(&mm->ioctx_lock); | |
db446a08 | 1002 | mm->ioctx_table = NULL; |
858f0993 AD |
1003 | #endif |
1004 | } | |
1005 | ||
c3f3ce04 AA |
1006 | static __always_inline void mm_clear_owner(struct mm_struct *mm, |
1007 | struct task_struct *p) | |
1008 | { | |
1009 | #ifdef CONFIG_MEMCG | |
1010 | if (mm->owner == p) | |
1011 | WRITE_ONCE(mm->owner, NULL); | |
1012 | #endif | |
1013 | } | |
1014 | ||
33144e84 VD |
1015 | static void mm_init_owner(struct mm_struct *mm, struct task_struct *p) |
1016 | { | |
1017 | #ifdef CONFIG_MEMCG | |
1018 | mm->owner = p; | |
1019 | #endif | |
1020 | } | |
1021 | ||
82e69a12 FY |
1022 | static void mm_init_pasid(struct mm_struct *mm) |
1023 | { | |
1024 | #ifdef CONFIG_IOMMU_SUPPORT | |
1025 | mm->pasid = INIT_PASID; | |
1026 | #endif | |
1027 | } | |
1028 | ||
355627f5 EB |
1029 | static void mm_init_uprobes_state(struct mm_struct *mm) |
1030 | { | |
1031 | #ifdef CONFIG_UPROBES | |
1032 | mm->uprobes_state.xol_area = NULL; | |
1033 | #endif | |
1034 | } | |
1035 | ||
bfedb589 EB |
1036 | static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p, |
1037 | struct user_namespace *user_ns) | |
1da177e4 | 1038 | { |
41f727fd VD |
1039 | mm->mmap = NULL; |
1040 | mm->mm_rb = RB_ROOT; | |
1041 | mm->vmacache_seqnum = 0; | |
1da177e4 LT |
1042 | atomic_set(&mm->mm_users, 1); |
1043 | atomic_set(&mm->mm_count, 1); | |
57efa1fe | 1044 | seqcount_init(&mm->write_protect_seq); |
d8ed45c5 | 1045 | mmap_init_lock(mm); |
1da177e4 | 1046 | INIT_LIST_HEAD(&mm->mmlist); |
af5b0f6a | 1047 | mm_pgtables_bytes_init(mm); |
41f727fd VD |
1048 | mm->map_count = 0; |
1049 | mm->locked_vm = 0; | |
70f8a3ca | 1050 | atomic64_set(&mm->pinned_vm, 0); |
d559db08 | 1051 | memset(&mm->rss_stat, 0, sizeof(mm->rss_stat)); |
1da177e4 | 1052 | spin_lock_init(&mm->page_table_lock); |
88aa7cc6 | 1053 | spin_lock_init(&mm->arg_lock); |
41f727fd | 1054 | mm_init_cpumask(mm); |
858f0993 | 1055 | mm_init_aio(mm); |
cf475ad2 | 1056 | mm_init_owner(mm, p); |
82e69a12 | 1057 | mm_init_pasid(mm); |
2b7e8665 | 1058 | RCU_INIT_POINTER(mm->exe_file, NULL); |
984cfe4e | 1059 | mmu_notifier_subscriptions_init(mm); |
16af97dc | 1060 | init_tlb_flush_pending(mm); |
41f727fd VD |
1061 | #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS |
1062 | mm->pmd_huge_pte = NULL; | |
1063 | #endif | |
355627f5 | 1064 | mm_init_uprobes_state(mm); |
13db8c50 | 1065 | hugetlb_count_init(mm); |
1da177e4 | 1066 | |
a0715cc2 AT |
1067 | if (current->mm) { |
1068 | mm->flags = current->mm->flags & MMF_INIT_MASK; | |
1069 | mm->def_flags = current->mm->def_flags & VM_INIT_DEF_MASK; | |
1070 | } else { | |
1071 | mm->flags = default_dump_filter; | |
1da177e4 | 1072 | mm->def_flags = 0; |
a0715cc2 AT |
1073 | } |
1074 | ||
41f727fd VD |
1075 | if (mm_alloc_pgd(mm)) |
1076 | goto fail_nopgd; | |
1077 | ||
1078 | if (init_new_context(p, mm)) | |
1079 | goto fail_nocontext; | |
78fb7466 | 1080 | |
bfedb589 | 1081 | mm->user_ns = get_user_ns(user_ns); |
41f727fd VD |
1082 | return mm; |
1083 | ||
1084 | fail_nocontext: | |
1085 | mm_free_pgd(mm); | |
1086 | fail_nopgd: | |
1da177e4 LT |
1087 | free_mm(mm); |
1088 | return NULL; | |
1089 | } | |
1090 | ||
1091 | /* | |
1092 | * Allocate and initialize an mm_struct. | |
1093 | */ | |
fb0a685c | 1094 | struct mm_struct *mm_alloc(void) |
1da177e4 | 1095 | { |
fb0a685c | 1096 | struct mm_struct *mm; |
1da177e4 LT |
1097 | |
1098 | mm = allocate_mm(); | |
de03c72c KM |
1099 | if (!mm) |
1100 | return NULL; | |
1101 | ||
1102 | memset(mm, 0, sizeof(*mm)); | |
bfedb589 | 1103 | return mm_init(mm, current, current_user_ns()); |
1da177e4 LT |
1104 | } |
1105 | ||
ec8d7c14 MH |
1106 | static inline void __mmput(struct mm_struct *mm) |
1107 | { | |
1108 | VM_BUG_ON(atomic_read(&mm->mm_users)); | |
1109 | ||
1110 | uprobe_clear_state(mm); | |
1111 | exit_aio(mm); | |
1112 | ksm_exit(mm); | |
1113 | khugepaged_exit(mm); /* must run before exit_mmap */ | |
1114 | exit_mmap(mm); | |
6fcb52a5 | 1115 | mm_put_huge_zero_page(mm); |
ec8d7c14 MH |
1116 | set_mm_exe_file(mm, NULL); |
1117 | if (!list_empty(&mm->mmlist)) { | |
1118 | spin_lock(&mmlist_lock); | |
1119 | list_del(&mm->mmlist); | |
1120 | spin_unlock(&mmlist_lock); | |
1121 | } | |
1122 | if (mm->binfmt) | |
1123 | module_put(mm->binfmt->module); | |
1124 | mmdrop(mm); | |
1125 | } | |
1126 | ||
1da177e4 LT |
1127 | /* |
1128 | * Decrement the use count and release all resources for an mm. | |
1129 | */ | |
1130 | void mmput(struct mm_struct *mm) | |
1131 | { | |
0ae26f1b AM |
1132 | might_sleep(); |
1133 | ||
ec8d7c14 MH |
1134 | if (atomic_dec_and_test(&mm->mm_users)) |
1135 | __mmput(mm); | |
1136 | } | |
1137 | EXPORT_SYMBOL_GPL(mmput); | |
1138 | ||
a1b2289c SY |
1139 | #ifdef CONFIG_MMU |
1140 | static void mmput_async_fn(struct work_struct *work) | |
1141 | { | |
1142 | struct mm_struct *mm = container_of(work, struct mm_struct, | |
1143 | async_put_work); | |
1144 | ||
1145 | __mmput(mm); | |
1146 | } | |
1147 | ||
1148 | void mmput_async(struct mm_struct *mm) | |
1149 | { | |
1150 | if (atomic_dec_and_test(&mm->mm_users)) { | |
1151 | INIT_WORK(&mm->async_put_work, mmput_async_fn); | |
1152 | schedule_work(&mm->async_put_work); | |
1153 | } | |
1154 | } | |
1155 | #endif | |
1156 | ||
90f31d0e KK |
1157 | /** |
1158 | * set_mm_exe_file - change a reference to the mm's executable file | |
1159 | * | |
1160 | * This changes mm's executable file (shown as symlink /proc/[pid]/exe). | |
1161 | * | |
6e399cd1 DB |
1162 | * Main users are mmput() and sys_execve(). Callers prevent concurrent |
1163 | * invocations: in mmput() nobody alive left, in execve task is single | |
35d7bdc8 | 1164 | * threaded. |
fe69d560 DH |
1165 | * |
1166 | * Can only fail if new_exe_file != NULL. | |
90f31d0e | 1167 | */ |
fe69d560 | 1168 | int set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file) |
38646013 | 1169 | { |
6e399cd1 DB |
1170 | struct file *old_exe_file; |
1171 | ||
1172 | /* | |
1173 | * It is safe to dereference the exe_file without RCU as | |
1174 | * this function is only called if nobody else can access | |
1175 | * this mm -- see comment above for justification. | |
1176 | */ | |
1177 | old_exe_file = rcu_dereference_raw(mm->exe_file); | |
90f31d0e | 1178 | |
fe69d560 DH |
1179 | if (new_exe_file) { |
1180 | /* | |
1181 | * We expect the caller (i.e., sys_execve) to already denied | |
1182 | * write access, so this is unlikely to fail. | |
1183 | */ | |
1184 | if (unlikely(deny_write_access(new_exe_file))) | |
1185 | return -EACCES; | |
38646013 | 1186 | get_file(new_exe_file); |
fe69d560 | 1187 | } |
90f31d0e | 1188 | rcu_assign_pointer(mm->exe_file, new_exe_file); |
fe69d560 DH |
1189 | if (old_exe_file) { |
1190 | allow_write_access(old_exe_file); | |
90f31d0e | 1191 | fput(old_exe_file); |
fe69d560 DH |
1192 | } |
1193 | return 0; | |
38646013 JS |
1194 | } |
1195 | ||
35d7bdc8 DH |
1196 | /** |
1197 | * replace_mm_exe_file - replace a reference to the mm's executable file | |
1198 | * | |
1199 | * This changes mm's executable file (shown as symlink /proc/[pid]/exe), | |
1200 | * dealing with concurrent invocation and without grabbing the mmap lock in | |
1201 | * write mode. | |
1202 | * | |
1203 | * Main user is sys_prctl(PR_SET_MM_MAP/EXE_FILE). | |
1204 | */ | |
1205 | int replace_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file) | |
1206 | { | |
1207 | struct vm_area_struct *vma; | |
1208 | struct file *old_exe_file; | |
1209 | int ret = 0; | |
1210 | ||
1211 | /* Forbid mm->exe_file change if old file still mapped. */ | |
1212 | old_exe_file = get_mm_exe_file(mm); | |
1213 | if (old_exe_file) { | |
1214 | mmap_read_lock(mm); | |
1215 | for (vma = mm->mmap; vma && !ret; vma = vma->vm_next) { | |
1216 | if (!vma->vm_file) | |
1217 | continue; | |
1218 | if (path_equal(&vma->vm_file->f_path, | |
1219 | &old_exe_file->f_path)) | |
1220 | ret = -EBUSY; | |
1221 | } | |
1222 | mmap_read_unlock(mm); | |
1223 | fput(old_exe_file); | |
1224 | if (ret) | |
1225 | return ret; | |
1226 | } | |
1227 | ||
1228 | /* set the new file, lockless */ | |
fe69d560 DH |
1229 | ret = deny_write_access(new_exe_file); |
1230 | if (ret) | |
1231 | return -EACCES; | |
35d7bdc8 | 1232 | get_file(new_exe_file); |
fe69d560 | 1233 | |
35d7bdc8 | 1234 | old_exe_file = xchg(&mm->exe_file, new_exe_file); |
fe69d560 DH |
1235 | if (old_exe_file) { |
1236 | /* | |
1237 | * Don't race with dup_mmap() getting the file and disallowing | |
1238 | * write access while someone might open the file writable. | |
1239 | */ | |
1240 | mmap_read_lock(mm); | |
1241 | allow_write_access(old_exe_file); | |
35d7bdc8 | 1242 | fput(old_exe_file); |
fe69d560 DH |
1243 | mmap_read_unlock(mm); |
1244 | } | |
35d7bdc8 | 1245 | return 0; |
38646013 JS |
1246 | } |
1247 | ||
90f31d0e KK |
1248 | /** |
1249 | * get_mm_exe_file - acquire a reference to the mm's executable file | |
1250 | * | |
1251 | * Returns %NULL if mm has no associated executable file. | |
1252 | * User must release file via fput(). | |
1253 | */ | |
38646013 JS |
1254 | struct file *get_mm_exe_file(struct mm_struct *mm) |
1255 | { | |
1256 | struct file *exe_file; | |
1257 | ||
90f31d0e KK |
1258 | rcu_read_lock(); |
1259 | exe_file = rcu_dereference(mm->exe_file); | |
1260 | if (exe_file && !get_file_rcu(exe_file)) | |
1261 | exe_file = NULL; | |
1262 | rcu_read_unlock(); | |
38646013 JS |
1263 | return exe_file; |
1264 | } | |
1265 | ||
cd81a917 MG |
1266 | /** |
1267 | * get_task_exe_file - acquire a reference to the task's executable file | |
1268 | * | |
1269 | * Returns %NULL if task's mm (if any) has no associated executable file or | |
1270 | * this is a kernel thread with borrowed mm (see the comment above get_task_mm). | |
1271 | * User must release file via fput(). | |
1272 | */ | |
1273 | struct file *get_task_exe_file(struct task_struct *task) | |
1274 | { | |
1275 | struct file *exe_file = NULL; | |
1276 | struct mm_struct *mm; | |
1277 | ||
1278 | task_lock(task); | |
1279 | mm = task->mm; | |
1280 | if (mm) { | |
1281 | if (!(task->flags & PF_KTHREAD)) | |
1282 | exe_file = get_mm_exe_file(mm); | |
1283 | } | |
1284 | task_unlock(task); | |
1285 | return exe_file; | |
1286 | } | |
38646013 | 1287 | |
1da177e4 LT |
1288 | /** |
1289 | * get_task_mm - acquire a reference to the task's mm | |
1290 | * | |
246bb0b1 | 1291 | * Returns %NULL if the task has no mm. Checks PF_KTHREAD (meaning |
1da177e4 LT |
1292 | * this kernel workthread has transiently adopted a user mm with use_mm, |
1293 | * to do its AIO) is not set and if so returns a reference to it, after | |
1294 | * bumping up the use count. User must release the mm via mmput() | |
1295 | * after use. Typically used by /proc and ptrace. | |
1296 | */ | |
1297 | struct mm_struct *get_task_mm(struct task_struct *task) | |
1298 | { | |
1299 | struct mm_struct *mm; | |
1300 | ||
1301 | task_lock(task); | |
1302 | mm = task->mm; | |
1303 | if (mm) { | |
246bb0b1 | 1304 | if (task->flags & PF_KTHREAD) |
1da177e4 LT |
1305 | mm = NULL; |
1306 | else | |
3fce371b | 1307 | mmget(mm); |
1da177e4 LT |
1308 | } |
1309 | task_unlock(task); | |
1310 | return mm; | |
1311 | } | |
1312 | EXPORT_SYMBOL_GPL(get_task_mm); | |
1313 | ||
8cdb878d CY |
1314 | struct mm_struct *mm_access(struct task_struct *task, unsigned int mode) |
1315 | { | |
1316 | struct mm_struct *mm; | |
1317 | int err; | |
1318 | ||
f7cfd871 | 1319 | err = down_read_killable(&task->signal->exec_update_lock); |
8cdb878d CY |
1320 | if (err) |
1321 | return ERR_PTR(err); | |
1322 | ||
1323 | mm = get_task_mm(task); | |
1324 | if (mm && mm != current->mm && | |
1325 | !ptrace_may_access(task, mode)) { | |
1326 | mmput(mm); | |
1327 | mm = ERR_PTR(-EACCES); | |
1328 | } | |
f7cfd871 | 1329 | up_read(&task->signal->exec_update_lock); |
8cdb878d CY |
1330 | |
1331 | return mm; | |
1332 | } | |
1333 | ||
57b59c4a | 1334 | static void complete_vfork_done(struct task_struct *tsk) |
c415c3b4 | 1335 | { |
d68b46fe | 1336 | struct completion *vfork; |
c415c3b4 | 1337 | |
d68b46fe ON |
1338 | task_lock(tsk); |
1339 | vfork = tsk->vfork_done; | |
1340 | if (likely(vfork)) { | |
1341 | tsk->vfork_done = NULL; | |
1342 | complete(vfork); | |
1343 | } | |
1344 | task_unlock(tsk); | |
1345 | } | |
1346 | ||
1347 | static int wait_for_vfork_done(struct task_struct *child, | |
1348 | struct completion *vfork) | |
1349 | { | |
1350 | int killed; | |
1351 | ||
1352 | freezer_do_not_count(); | |
76f969e8 | 1353 | cgroup_enter_frozen(); |
d68b46fe | 1354 | killed = wait_for_completion_killable(vfork); |
76f969e8 | 1355 | cgroup_leave_frozen(false); |
d68b46fe ON |
1356 | freezer_count(); |
1357 | ||
1358 | if (killed) { | |
1359 | task_lock(child); | |
1360 | child->vfork_done = NULL; | |
1361 | task_unlock(child); | |
1362 | } | |
1363 | ||
1364 | put_task_struct(child); | |
1365 | return killed; | |
c415c3b4 ON |
1366 | } |
1367 | ||
1da177e4 LT |
1368 | /* Please note the differences between mmput and mm_release. |
1369 | * mmput is called whenever we stop holding onto a mm_struct, | |
1370 | * error success whatever. | |
1371 | * | |
1372 | * mm_release is called after a mm_struct has been removed | |
1373 | * from the current process. | |
1374 | * | |
1375 | * This difference is important for error handling, when we | |
1376 | * only half set up a mm_struct for a new process and need to restore | |
1377 | * the old one. Because we mmput the new mm_struct before | |
1378 | * restoring the old one. . . | |
1379 | * Eric Biederman 10 January 1998 | |
1380 | */ | |
4610ba7a | 1381 | static void mm_release(struct task_struct *tsk, struct mm_struct *mm) |
1da177e4 | 1382 | { |
0326f5a9 SD |
1383 | uprobe_free_utask(tsk); |
1384 | ||
1da177e4 LT |
1385 | /* Get rid of any cached register state */ |
1386 | deactivate_mm(tsk, mm); | |
1387 | ||
fec1d011 | 1388 | /* |
735f2770 MH |
1389 | * Signal userspace if we're not exiting with a core dump |
1390 | * because we want to leave the value intact for debugging | |
1391 | * purposes. | |
fec1d011 | 1392 | */ |
9c8a8228 | 1393 | if (tsk->clear_child_tid) { |
92307383 | 1394 | if (atomic_read(&mm->mm_users) > 1) { |
9c8a8228 ED |
1395 | /* |
1396 | * We don't check the error code - if userspace has | |
1397 | * not set up a proper pointer then tough luck. | |
1398 | */ | |
1399 | put_user(0, tsk->clear_child_tid); | |
2de0db99 DB |
1400 | do_futex(tsk->clear_child_tid, FUTEX_WAKE, |
1401 | 1, NULL, NULL, 0, 0); | |
9c8a8228 | 1402 | } |
1da177e4 | 1403 | tsk->clear_child_tid = NULL; |
1da177e4 | 1404 | } |
f7505d64 KK |
1405 | |
1406 | /* | |
1407 | * All done, finally we can wake up parent and return this mm to him. | |
1408 | * Also kthread_stop() uses this completion for synchronization. | |
1409 | */ | |
1410 | if (tsk->vfork_done) | |
1411 | complete_vfork_done(tsk); | |
1da177e4 LT |
1412 | } |
1413 | ||
4610ba7a TG |
1414 | void exit_mm_release(struct task_struct *tsk, struct mm_struct *mm) |
1415 | { | |
150d7158 | 1416 | futex_exit_release(tsk); |
4610ba7a TG |
1417 | mm_release(tsk, mm); |
1418 | } | |
1419 | ||
1420 | void exec_mm_release(struct task_struct *tsk, struct mm_struct *mm) | |
1421 | { | |
150d7158 | 1422 | futex_exec_release(tsk); |
4610ba7a TG |
1423 | mm_release(tsk, mm); |
1424 | } | |
1425 | ||
13585fa0 NA |
1426 | /** |
1427 | * dup_mm() - duplicates an existing mm structure | |
1428 | * @tsk: the task_struct with which the new mm will be associated. | |
1429 | * @oldmm: the mm to duplicate. | |
1430 | * | |
1431 | * Allocates a new mm structure and duplicates the provided @oldmm structure | |
1432 | * content into it. | |
1433 | * | |
1434 | * Return: the duplicated mm or NULL on failure. | |
a0a7ec30 | 1435 | */ |
13585fa0 NA |
1436 | static struct mm_struct *dup_mm(struct task_struct *tsk, |
1437 | struct mm_struct *oldmm) | |
a0a7ec30 | 1438 | { |
13585fa0 | 1439 | struct mm_struct *mm; |
a0a7ec30 JD |
1440 | int err; |
1441 | ||
a0a7ec30 JD |
1442 | mm = allocate_mm(); |
1443 | if (!mm) | |
1444 | goto fail_nomem; | |
1445 | ||
1446 | memcpy(mm, oldmm, sizeof(*mm)); | |
1447 | ||
bfedb589 | 1448 | if (!mm_init(mm, tsk, mm->user_ns)) |
a0a7ec30 JD |
1449 | goto fail_nomem; |
1450 | ||
a0a7ec30 JD |
1451 | err = dup_mmap(mm, oldmm); |
1452 | if (err) | |
1453 | goto free_pt; | |
1454 | ||
1455 | mm->hiwater_rss = get_mm_rss(mm); | |
1456 | mm->hiwater_vm = mm->total_vm; | |
1457 | ||
801460d0 HS |
1458 | if (mm->binfmt && !try_module_get(mm->binfmt->module)) |
1459 | goto free_pt; | |
1460 | ||
a0a7ec30 JD |
1461 | return mm; |
1462 | ||
1463 | free_pt: | |
801460d0 HS |
1464 | /* don't put binfmt in mmput, we haven't got module yet */ |
1465 | mm->binfmt = NULL; | |
c3f3ce04 | 1466 | mm_init_owner(mm, NULL); |
a0a7ec30 JD |
1467 | mmput(mm); |
1468 | ||
1469 | fail_nomem: | |
1470 | return NULL; | |
a0a7ec30 JD |
1471 | } |
1472 | ||
fb0a685c | 1473 | static int copy_mm(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 | 1474 | { |
fb0a685c | 1475 | struct mm_struct *mm, *oldmm; |
1da177e4 LT |
1476 | |
1477 | tsk->min_flt = tsk->maj_flt = 0; | |
1478 | tsk->nvcsw = tsk->nivcsw = 0; | |
17406b82 MSB |
1479 | #ifdef CONFIG_DETECT_HUNG_TASK |
1480 | tsk->last_switch_count = tsk->nvcsw + tsk->nivcsw; | |
a2e51445 | 1481 | tsk->last_switch_time = 0; |
17406b82 | 1482 | #endif |
1da177e4 LT |
1483 | |
1484 | tsk->mm = NULL; | |
1485 | tsk->active_mm = NULL; | |
1486 | ||
1487 | /* | |
1488 | * Are we cloning a kernel thread? | |
1489 | * | |
1490 | * We need to steal a active VM for that.. | |
1491 | */ | |
1492 | oldmm = current->mm; | |
1493 | if (!oldmm) | |
1494 | return 0; | |
1495 | ||
615d6e87 DB |
1496 | /* initialize the new vmacache entries */ |
1497 | vmacache_flush(tsk); | |
1498 | ||
1da177e4 | 1499 | if (clone_flags & CLONE_VM) { |
3fce371b | 1500 | mmget(oldmm); |
1da177e4 | 1501 | mm = oldmm; |
a6895399 REB |
1502 | } else { |
1503 | mm = dup_mm(tsk, current->mm); | |
1504 | if (!mm) | |
1505 | return -ENOMEM; | |
1da177e4 LT |
1506 | } |
1507 | ||
1da177e4 LT |
1508 | tsk->mm = mm; |
1509 | tsk->active_mm = mm; | |
1510 | return 0; | |
1da177e4 LT |
1511 | } |
1512 | ||
a39bc516 | 1513 | static int copy_fs(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 | 1514 | { |
498052bb | 1515 | struct fs_struct *fs = current->fs; |
1da177e4 | 1516 | if (clone_flags & CLONE_FS) { |
498052bb | 1517 | /* tsk->fs is already what we want */ |
2a4419b5 | 1518 | spin_lock(&fs->lock); |
498052bb | 1519 | if (fs->in_exec) { |
2a4419b5 | 1520 | spin_unlock(&fs->lock); |
498052bb AV |
1521 | return -EAGAIN; |
1522 | } | |
1523 | fs->users++; | |
2a4419b5 | 1524 | spin_unlock(&fs->lock); |
1da177e4 LT |
1525 | return 0; |
1526 | } | |
498052bb | 1527 | tsk->fs = copy_fs_struct(fs); |
1da177e4 LT |
1528 | if (!tsk->fs) |
1529 | return -ENOMEM; | |
1530 | return 0; | |
1531 | } | |
1532 | ||
fb0a685c | 1533 | static int copy_files(unsigned long clone_flags, struct task_struct *tsk) |
a016f338 JD |
1534 | { |
1535 | struct files_struct *oldf, *newf; | |
1536 | int error = 0; | |
1537 | ||
1538 | /* | |
1539 | * A background process may not have any files ... | |
1540 | */ | |
1541 | oldf = current->files; | |
1542 | if (!oldf) | |
1543 | goto out; | |
1544 | ||
1545 | if (clone_flags & CLONE_FILES) { | |
1546 | atomic_inc(&oldf->count); | |
1547 | goto out; | |
1548 | } | |
1549 | ||
60997c3d | 1550 | newf = dup_fd(oldf, NR_OPEN_MAX, &error); |
a016f338 JD |
1551 | if (!newf) |
1552 | goto out; | |
1553 | ||
1554 | tsk->files = newf; | |
1555 | error = 0; | |
1556 | out: | |
1557 | return error; | |
1558 | } | |
1559 | ||
a39bc516 | 1560 | static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
1561 | { |
1562 | struct sighand_struct *sig; | |
1563 | ||
60348802 | 1564 | if (clone_flags & CLONE_SIGHAND) { |
d036bda7 | 1565 | refcount_inc(¤t->sighand->count); |
1da177e4 LT |
1566 | return 0; |
1567 | } | |
1568 | sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); | |
0c282b06 | 1569 | RCU_INIT_POINTER(tsk->sighand, sig); |
1da177e4 LT |
1570 | if (!sig) |
1571 | return -ENOMEM; | |
9d7fb042 | 1572 | |
d036bda7 | 1573 | refcount_set(&sig->count, 1); |
06e62a46 | 1574 | spin_lock_irq(¤t->sighand->siglock); |
1da177e4 | 1575 | memcpy(sig->action, current->sighand->action, sizeof(sig->action)); |
06e62a46 | 1576 | spin_unlock_irq(¤t->sighand->siglock); |
b612e5df CB |
1577 | |
1578 | /* Reset all signal handler not set to SIG_IGN to SIG_DFL. */ | |
1579 | if (clone_flags & CLONE_CLEAR_SIGHAND) | |
1580 | flush_signal_handlers(tsk, 0); | |
1581 | ||
1da177e4 LT |
1582 | return 0; |
1583 | } | |
1584 | ||
a7e5328a | 1585 | void __cleanup_sighand(struct sighand_struct *sighand) |
c81addc9 | 1586 | { |
d036bda7 | 1587 | if (refcount_dec_and_test(&sighand->count)) { |
d80e731e | 1588 | signalfd_cleanup(sighand); |
392809b2 | 1589 | /* |
5f0d5a3a | 1590 | * sighand_cachep is SLAB_TYPESAFE_BY_RCU so we can free it |
392809b2 ON |
1591 | * without an RCU grace period, see __lock_task_sighand(). |
1592 | */ | |
c81addc9 | 1593 | kmem_cache_free(sighand_cachep, sighand); |
d80e731e | 1594 | } |
c81addc9 ON |
1595 | } |
1596 | ||
f06febc9 FM |
1597 | /* |
1598 | * Initialize POSIX timer handling for a thread group. | |
1599 | */ | |
1600 | static void posix_cpu_timers_init_group(struct signal_struct *sig) | |
1601 | { | |
2b69942f | 1602 | struct posix_cputimers *pct = &sig->posix_cputimers; |
78d7d407 JS |
1603 | unsigned long cpu_limit; |
1604 | ||
316c1608 | 1605 | cpu_limit = READ_ONCE(sig->rlim[RLIMIT_CPU].rlim_cur); |
3a245c0f | 1606 | posix_cputimers_group_init(pct, cpu_limit); |
f06febc9 FM |
1607 | } |
1608 | ||
a39bc516 | 1609 | static int copy_signal(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
1610 | { |
1611 | struct signal_struct *sig; | |
1da177e4 | 1612 | |
4ab6c083 | 1613 | if (clone_flags & CLONE_THREAD) |
490dea45 | 1614 | return 0; |
490dea45 | 1615 | |
a56704ef | 1616 | sig = kmem_cache_zalloc(signal_cachep, GFP_KERNEL); |
1da177e4 LT |
1617 | tsk->signal = sig; |
1618 | if (!sig) | |
1619 | return -ENOMEM; | |
1620 | ||
b3ac022c | 1621 | sig->nr_threads = 1; |
1da177e4 | 1622 | atomic_set(&sig->live, 1); |
60d4de3f | 1623 | refcount_set(&sig->sigcnt, 1); |
0c740d0a ON |
1624 | |
1625 | /* list_add(thread_node, thread_head) without INIT_LIST_HEAD() */ | |
1626 | sig->thread_head = (struct list_head)LIST_HEAD_INIT(tsk->thread_node); | |
1627 | tsk->thread_node = (struct list_head)LIST_HEAD_INIT(sig->thread_head); | |
1628 | ||
1da177e4 | 1629 | init_waitqueue_head(&sig->wait_chldexit); |
db51aecc | 1630 | sig->curr_target = tsk; |
1da177e4 | 1631 | init_sigpending(&sig->shared_pending); |
c3ad2c3b | 1632 | INIT_HLIST_HEAD(&sig->multiprocess); |
e78c3496 | 1633 | seqlock_init(&sig->stats_lock); |
9d7fb042 | 1634 | prev_cputime_init(&sig->prev_cputime); |
1da177e4 | 1635 | |
baa73d9e | 1636 | #ifdef CONFIG_POSIX_TIMERS |
b18b6a9c | 1637 | INIT_LIST_HEAD(&sig->posix_timers); |
c9cb2e3d | 1638 | hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); |
1da177e4 | 1639 | sig->real_timer.function = it_real_fn; |
baa73d9e | 1640 | #endif |
1da177e4 | 1641 | |
1da177e4 LT |
1642 | task_lock(current->group_leader); |
1643 | memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim); | |
1644 | task_unlock(current->group_leader); | |
1645 | ||
6279a751 ON |
1646 | posix_cpu_timers_init_group(sig); |
1647 | ||
522ed776 | 1648 | tty_audit_fork(sig); |
5091faa4 | 1649 | sched_autogroup_fork(sig); |
522ed776 | 1650 | |
a63d83f4 | 1651 | sig->oom_score_adj = current->signal->oom_score_adj; |
dabb16f6 | 1652 | sig->oom_score_adj_min = current->signal->oom_score_adj_min; |
28b83c51 | 1653 | |
9b1bf12d | 1654 | mutex_init(&sig->cred_guard_mutex); |
f7cfd871 | 1655 | init_rwsem(&sig->exec_update_lock); |
9b1bf12d | 1656 | |
1da177e4 LT |
1657 | return 0; |
1658 | } | |
1659 | ||
dbd95212 KC |
1660 | static void copy_seccomp(struct task_struct *p) |
1661 | { | |
1662 | #ifdef CONFIG_SECCOMP | |
1663 | /* | |
1664 | * Must be called with sighand->lock held, which is common to | |
1665 | * all threads in the group. Holding cred_guard_mutex is not | |
1666 | * needed because this new task is not yet running and cannot | |
1667 | * be racing exec. | |
1668 | */ | |
69f6a34b | 1669 | assert_spin_locked(¤t->sighand->siglock); |
dbd95212 KC |
1670 | |
1671 | /* Ref-count the new filter user, and assign it. */ | |
1672 | get_seccomp_filter(current); | |
1673 | p->seccomp = current->seccomp; | |
1674 | ||
1675 | /* | |
1676 | * Explicitly enable no_new_privs here in case it got set | |
1677 | * between the task_struct being duplicated and holding the | |
1678 | * sighand lock. The seccomp state and nnp must be in sync. | |
1679 | */ | |
1680 | if (task_no_new_privs(current)) | |
1681 | task_set_no_new_privs(p); | |
1682 | ||
1683 | /* | |
1684 | * If the parent gained a seccomp mode after copying thread | |
1685 | * flags and between before we held the sighand lock, we have | |
1686 | * to manually enable the seccomp thread flag here. | |
1687 | */ | |
1688 | if (p->seccomp.mode != SECCOMP_MODE_DISABLED) | |
23d67a54 | 1689 | set_task_syscall_work(p, SECCOMP); |
dbd95212 KC |
1690 | #endif |
1691 | } | |
1692 | ||
17da2bd9 | 1693 | SYSCALL_DEFINE1(set_tid_address, int __user *, tidptr) |
1da177e4 LT |
1694 | { |
1695 | current->clear_child_tid = tidptr; | |
1696 | ||
b488893a | 1697 | return task_pid_vnr(current); |
1da177e4 LT |
1698 | } |
1699 | ||
a39bc516 | 1700 | static void rt_mutex_init_task(struct task_struct *p) |
23f78d4a | 1701 | { |
1d615482 | 1702 | raw_spin_lock_init(&p->pi_lock); |
e29e175b | 1703 | #ifdef CONFIG_RT_MUTEXES |
a23ba907 | 1704 | p->pi_waiters = RB_ROOT_CACHED; |
e96a7705 | 1705 | p->pi_top_task = NULL; |
23f78d4a | 1706 | p->pi_blocked_on = NULL; |
23f78d4a IM |
1707 | #endif |
1708 | } | |
1709 | ||
2c470475 EB |
1710 | static inline void init_task_pid_links(struct task_struct *task) |
1711 | { | |
1712 | enum pid_type type; | |
1713 | ||
96e1e984 | 1714 | for (type = PIDTYPE_PID; type < PIDTYPE_MAX; ++type) |
2c470475 | 1715 | INIT_HLIST_NODE(&task->pid_links[type]); |
2c470475 EB |
1716 | } |
1717 | ||
81907739 ON |
1718 | static inline void |
1719 | init_task_pid(struct task_struct *task, enum pid_type type, struct pid *pid) | |
1720 | { | |
2c470475 EB |
1721 | if (type == PIDTYPE_PID) |
1722 | task->thread_pid = pid; | |
1723 | else | |
1724 | task->signal->pids[type] = pid; | |
81907739 ON |
1725 | } |
1726 | ||
6bfbaa51 IM |
1727 | static inline void rcu_copy_process(struct task_struct *p) |
1728 | { | |
1729 | #ifdef CONFIG_PREEMPT_RCU | |
1730 | p->rcu_read_lock_nesting = 0; | |
1731 | p->rcu_read_unlock_special.s = 0; | |
1732 | p->rcu_blocked_node = NULL; | |
1733 | INIT_LIST_HEAD(&p->rcu_node_entry); | |
1734 | #endif /* #ifdef CONFIG_PREEMPT_RCU */ | |
1735 | #ifdef CONFIG_TASKS_RCU | |
1736 | p->rcu_tasks_holdout = false; | |
1737 | INIT_LIST_HEAD(&p->rcu_tasks_holdout_list); | |
1738 | p->rcu_tasks_idle_cpu = -1; | |
1739 | #endif /* #ifdef CONFIG_TASKS_RCU */ | |
d5f177d3 PM |
1740 | #ifdef CONFIG_TASKS_TRACE_RCU |
1741 | p->trc_reader_nesting = 0; | |
276c4104 | 1742 | p->trc_reader_special.s = 0; |
d5f177d3 PM |
1743 | INIT_LIST_HEAD(&p->trc_holdout_list); |
1744 | #endif /* #ifdef CONFIG_TASKS_TRACE_RCU */ | |
6bfbaa51 IM |
1745 | } |
1746 | ||
3695eae5 CB |
1747 | struct pid *pidfd_pid(const struct file *file) |
1748 | { | |
1749 | if (file->f_op == &pidfd_fops) | |
1750 | return file->private_data; | |
1751 | ||
1752 | return ERR_PTR(-EBADF); | |
1753 | } | |
1754 | ||
b3e58382 CB |
1755 | static int pidfd_release(struct inode *inode, struct file *file) |
1756 | { | |
1757 | struct pid *pid = file->private_data; | |
1758 | ||
1759 | file->private_data = NULL; | |
1760 | put_pid(pid); | |
1761 | return 0; | |
1762 | } | |
1763 | ||
1764 | #ifdef CONFIG_PROC_FS | |
15d42eb2 CK |
1765 | /** |
1766 | * pidfd_show_fdinfo - print information about a pidfd | |
1767 | * @m: proc fdinfo file | |
1768 | * @f: file referencing a pidfd | |
1769 | * | |
1770 | * Pid: | |
1771 | * This function will print the pid that a given pidfd refers to in the | |
1772 | * pid namespace of the procfs instance. | |
1773 | * If the pid namespace of the process is not a descendant of the pid | |
1774 | * namespace of the procfs instance 0 will be shown as its pid. This is | |
1775 | * similar to calling getppid() on a process whose parent is outside of | |
1776 | * its pid namespace. | |
1777 | * | |
1778 | * NSpid: | |
1779 | * If pid namespaces are supported then this function will also print | |
1780 | * the pid of a given pidfd refers to for all descendant pid namespaces | |
1781 | * starting from the current pid namespace of the instance, i.e. the | |
1782 | * Pid field and the first entry in the NSpid field will be identical. | |
1783 | * If the pid namespace of the process is not a descendant of the pid | |
1784 | * namespace of the procfs instance 0 will be shown as its first NSpid | |
1785 | * entry and no others will be shown. | |
1786 | * Note that this differs from the Pid and NSpid fields in | |
1787 | * /proc/<pid>/status where Pid and NSpid are always shown relative to | |
1788 | * the pid namespace of the procfs instance. The difference becomes | |
1789 | * obvious when sending around a pidfd between pid namespaces from a | |
a8ca6b13 | 1790 | * different branch of the tree, i.e. where no ancestral relation is |
15d42eb2 CK |
1791 | * present between the pid namespaces: |
1792 | * - create two new pid namespaces ns1 and ns2 in the initial pid | |
1793 | * namespace (also take care to create new mount namespaces in the | |
1794 | * new pid namespace and mount procfs) | |
1795 | * - create a process with a pidfd in ns1 | |
1796 | * - send pidfd from ns1 to ns2 | |
1797 | * - read /proc/self/fdinfo/<pidfd> and observe that both Pid and NSpid | |
1798 | * have exactly one entry, which is 0 | |
1799 | */ | |
b3e58382 CB |
1800 | static void pidfd_show_fdinfo(struct seq_file *m, struct file *f) |
1801 | { | |
b3e58382 | 1802 | struct pid *pid = f->private_data; |
3d6d8da4 CB |
1803 | struct pid_namespace *ns; |
1804 | pid_t nr = -1; | |
15d42eb2 | 1805 | |
3d6d8da4 | 1806 | if (likely(pid_has_task(pid, PIDTYPE_PID))) { |
9d78edea | 1807 | ns = proc_pid_ns(file_inode(m->file)->i_sb); |
3d6d8da4 CB |
1808 | nr = pid_nr_ns(pid, ns); |
1809 | } | |
1810 | ||
1811 | seq_put_decimal_ll(m, "Pid:\t", nr); | |
b3e58382 | 1812 | |
15d42eb2 | 1813 | #ifdef CONFIG_PID_NS |
3d6d8da4 CB |
1814 | seq_put_decimal_ll(m, "\nNSpid:\t", nr); |
1815 | if (nr > 0) { | |
15d42eb2 | 1816 | int i; |
b3e58382 | 1817 | |
15d42eb2 CK |
1818 | /* If nr is non-zero it means that 'pid' is valid and that |
1819 | * ns, i.e. the pid namespace associated with the procfs | |
1820 | * instance, is in the pid namespace hierarchy of pid. | |
1821 | * Start at one below the already printed level. | |
1822 | */ | |
1823 | for (i = ns->level + 1; i <= pid->level; i++) | |
3d6d8da4 | 1824 | seq_put_decimal_ll(m, "\t", pid->numbers[i].nr); |
15d42eb2 CK |
1825 | } |
1826 | #endif | |
b3e58382 CB |
1827 | seq_putc(m, '\n'); |
1828 | } | |
1829 | #endif | |
1830 | ||
b53b0b9d JFG |
1831 | /* |
1832 | * Poll support for process exit notification. | |
1833 | */ | |
9e77716a | 1834 | static __poll_t pidfd_poll(struct file *file, struct poll_table_struct *pts) |
b53b0b9d | 1835 | { |
b53b0b9d | 1836 | struct pid *pid = file->private_data; |
9e77716a | 1837 | __poll_t poll_flags = 0; |
b53b0b9d JFG |
1838 | |
1839 | poll_wait(file, &pid->wait_pidfd, pts); | |
1840 | ||
b53b0b9d JFG |
1841 | /* |
1842 | * Inform pollers only when the whole thread group exits. | |
1843 | * If the thread group leader exits before all other threads in the | |
1844 | * group, then poll(2) should block, similar to the wait(2) family. | |
1845 | */ | |
38fd525a | 1846 | if (thread_group_exited(pid)) |
9e77716a | 1847 | poll_flags = EPOLLIN | EPOLLRDNORM; |
b53b0b9d JFG |
1848 | |
1849 | return poll_flags; | |
1850 | } | |
1851 | ||
b3e58382 CB |
1852 | const struct file_operations pidfd_fops = { |
1853 | .release = pidfd_release, | |
b53b0b9d | 1854 | .poll = pidfd_poll, |
b3e58382 CB |
1855 | #ifdef CONFIG_PROC_FS |
1856 | .show_fdinfo = pidfd_show_fdinfo, | |
1857 | #endif | |
1858 | }; | |
1859 | ||
c3f3ce04 AA |
1860 | static void __delayed_free_task(struct rcu_head *rhp) |
1861 | { | |
1862 | struct task_struct *tsk = container_of(rhp, struct task_struct, rcu); | |
1863 | ||
1864 | free_task(tsk); | |
1865 | } | |
1866 | ||
1867 | static __always_inline void delayed_free_task(struct task_struct *tsk) | |
1868 | { | |
1869 | if (IS_ENABLED(CONFIG_MEMCG)) | |
1870 | call_rcu(&tsk->rcu, __delayed_free_task); | |
1871 | else | |
1872 | free_task(tsk); | |
1873 | } | |
1874 | ||
67197a4f SB |
1875 | static void copy_oom_score_adj(u64 clone_flags, struct task_struct *tsk) |
1876 | { | |
1877 | /* Skip if kernel thread */ | |
1878 | if (!tsk->mm) | |
1879 | return; | |
1880 | ||
1881 | /* Skip if spawning a thread or using vfork */ | |
1882 | if ((clone_flags & (CLONE_VM | CLONE_THREAD | CLONE_VFORK)) != CLONE_VM) | |
1883 | return; | |
1884 | ||
1885 | /* We need to synchronize with __set_oom_adj */ | |
1886 | mutex_lock(&oom_adj_mutex); | |
1887 | set_bit(MMF_MULTIPROCESS, &tsk->mm->flags); | |
1888 | /* Update the values in case they were changed after copy_signal */ | |
1889 | tsk->signal->oom_score_adj = current->signal->oom_score_adj; | |
1890 | tsk->signal->oom_score_adj_min = current->signal->oom_score_adj_min; | |
1891 | mutex_unlock(&oom_adj_mutex); | |
1892 | } | |
1893 | ||
1da177e4 LT |
1894 | /* |
1895 | * This creates a new process as a copy of the old one, | |
1896 | * but does not actually start it yet. | |
1897 | * | |
1898 | * It copies the registers, and all the appropriate | |
1899 | * parts of the process environment (as per the clone | |
1900 | * flags). The actual kick-off is left to the caller. | |
1901 | */ | |
0766f788 | 1902 | static __latent_entropy struct task_struct *copy_process( |
09a05394 | 1903 | struct pid *pid, |
3033f14a | 1904 | int trace, |
7f192e3c CB |
1905 | int node, |
1906 | struct kernel_clone_args *args) | |
1da177e4 | 1907 | { |
b3e58382 | 1908 | int pidfd = -1, retval; |
a24efe62 | 1909 | struct task_struct *p; |
c3ad2c3b | 1910 | struct multiprocess_signals delayed; |
6fd2fe49 | 1911 | struct file *pidfile = NULL; |
7f192e3c | 1912 | u64 clone_flags = args->flags; |
769071ac | 1913 | struct nsproxy *nsp = current->nsproxy; |
1da177e4 | 1914 | |
667b6094 MPS |
1915 | /* |
1916 | * Don't allow sharing the root directory with processes in a different | |
1917 | * namespace | |
1918 | */ | |
1da177e4 LT |
1919 | if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS)) |
1920 | return ERR_PTR(-EINVAL); | |
1921 | ||
e66eded8 EB |
1922 | if ((clone_flags & (CLONE_NEWUSER|CLONE_FS)) == (CLONE_NEWUSER|CLONE_FS)) |
1923 | return ERR_PTR(-EINVAL); | |
1924 | ||
1da177e4 LT |
1925 | /* |
1926 | * Thread groups must share signals as well, and detached threads | |
1927 | * can only be started up within the thread group. | |
1928 | */ | |
1929 | if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND)) | |
1930 | return ERR_PTR(-EINVAL); | |
1931 | ||
1932 | /* | |
1933 | * Shared signal handlers imply shared VM. By way of the above, | |
1934 | * thread groups also imply shared VM. Blocking this case allows | |
1935 | * for various simplifications in other code. | |
1936 | */ | |
1937 | if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM)) | |
1938 | return ERR_PTR(-EINVAL); | |
1939 | ||
123be07b SB |
1940 | /* |
1941 | * Siblings of global init remain as zombies on exit since they are | |
1942 | * not reaped by their parent (swapper). To solve this and to avoid | |
1943 | * multi-rooted process trees, prevent global and container-inits | |
1944 | * from creating siblings. | |
1945 | */ | |
1946 | if ((clone_flags & CLONE_PARENT) && | |
1947 | current->signal->flags & SIGNAL_UNKILLABLE) | |
1948 | return ERR_PTR(-EINVAL); | |
1949 | ||
8382fcac | 1950 | /* |
40a0d32d | 1951 | * If the new process will be in a different pid or user namespace |
faf00da5 | 1952 | * do not allow it to share a thread group with the forking task. |
8382fcac | 1953 | */ |
faf00da5 | 1954 | if (clone_flags & CLONE_THREAD) { |
40a0d32d | 1955 | if ((clone_flags & (CLONE_NEWUSER | CLONE_NEWPID)) || |
769071ac AV |
1956 | (task_active_pid_ns(current) != nsp->pid_ns_for_children)) |
1957 | return ERR_PTR(-EINVAL); | |
1958 | } | |
1959 | ||
1960 | /* | |
1961 | * If the new process will be in a different time namespace | |
1962 | * do not allow it to share VM or a thread group with the forking task. | |
1963 | */ | |
1964 | if (clone_flags & (CLONE_THREAD | CLONE_VM)) { | |
1965 | if (nsp->time_ns != nsp->time_ns_for_children) | |
40a0d32d ON |
1966 | return ERR_PTR(-EINVAL); |
1967 | } | |
8382fcac | 1968 | |
b3e58382 | 1969 | if (clone_flags & CLONE_PIDFD) { |
b3e58382 | 1970 | /* |
b3e58382 CB |
1971 | * - CLONE_DETACHED is blocked so that we can potentially |
1972 | * reuse it later for CLONE_PIDFD. | |
1973 | * - CLONE_THREAD is blocked until someone really needs it. | |
1974 | */ | |
7f192e3c | 1975 | if (clone_flags & (CLONE_DETACHED | CLONE_THREAD)) |
b3e58382 | 1976 | return ERR_PTR(-EINVAL); |
b3e58382 CB |
1977 | } |
1978 | ||
c3ad2c3b EB |
1979 | /* |
1980 | * Force any signals received before this point to be delivered | |
1981 | * before the fork happens. Collect up signals sent to multiple | |
1982 | * processes that happen during the fork and delay them so that | |
1983 | * they appear to happen after the fork. | |
1984 | */ | |
1985 | sigemptyset(&delayed.signal); | |
1986 | INIT_HLIST_NODE(&delayed.node); | |
1987 | ||
1988 | spin_lock_irq(¤t->sighand->siglock); | |
1989 | if (!(clone_flags & CLONE_THREAD)) | |
1990 | hlist_add_head(&delayed.node, ¤t->signal->multiprocess); | |
1991 | recalc_sigpending(); | |
1992 | spin_unlock_irq(¤t->sighand->siglock); | |
1993 | retval = -ERESTARTNOINTR; | |
66ae0d1e | 1994 | if (task_sigpending(current)) |
c3ad2c3b EB |
1995 | goto fork_out; |
1996 | ||
1da177e4 | 1997 | retval = -ENOMEM; |
725fc629 | 1998 | p = dup_task_struct(current, node); |
1da177e4 LT |
1999 | if (!p) |
2000 | goto fork_out; | |
b16b3855 JA |
2001 | if (args->io_thread) { |
2002 | /* | |
2003 | * Mark us an IO worker, and block any signal that isn't | |
2004 | * fatal or STOP | |
2005 | */ | |
cc440e87 | 2006 | p->flags |= PF_IO_WORKER; |
b16b3855 JA |
2007 | siginitsetinv(&p->blocked, sigmask(SIGKILL)|sigmask(SIGSTOP)); |
2008 | } | |
1da177e4 | 2009 | |
7f192e3c | 2010 | p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? args->child_tid : NULL; |
4d6501dc VN |
2011 | /* |
2012 | * Clear TID on mm_release()? | |
2013 | */ | |
7f192e3c | 2014 | p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? args->child_tid : NULL; |
4d6501dc | 2015 | |
f7e8b616 SR |
2016 | ftrace_graph_init_task(p); |
2017 | ||
bea493a0 PZ |
2018 | rt_mutex_init_task(p); |
2019 | ||
a21ee605 | 2020 | lockdep_assert_irqs_enabled(); |
d12c1a37 | 2021 | #ifdef CONFIG_PROVE_LOCKING |
de30a2b3 IM |
2022 | DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled); |
2023 | #endif | |
8f2f9c4d EB |
2024 | retval = copy_creds(p, clone_flags); |
2025 | if (retval < 0) | |
2026 | goto bad_fork_free; | |
2027 | ||
1da177e4 | 2028 | retval = -EAGAIN; |
21d1c5e3 | 2029 | if (is_ucounts_overlimit(task_ucounts(p), UCOUNT_RLIMIT_NPROC, rlimit(RLIMIT_NPROC))) { |
b57922b6 EP |
2030 | if (p->real_cred->user != INIT_USER && |
2031 | !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN)) | |
8f2f9c4d | 2032 | goto bad_fork_cleanup_count; |
1da177e4 | 2033 | } |
72fa5997 | 2034 | current->flags &= ~PF_NPROC_EXCEEDED; |
1da177e4 | 2035 | |
1da177e4 LT |
2036 | /* |
2037 | * If multiple threads are within copy_process(), then this check | |
2038 | * triggers too late. This doesn't hurt, the check is only there | |
2039 | * to stop root fork bombs. | |
2040 | */ | |
04ec93fe | 2041 | retval = -EAGAIN; |
c17d1a3a | 2042 | if (data_race(nr_threads >= max_threads)) |
1da177e4 LT |
2043 | goto bad_fork_cleanup_count; |
2044 | ||
ca74e92b | 2045 | delayacct_tsk_init(p); /* Must remain after dup_task_struct() */ |
a8ea6fc9 | 2046 | p->flags &= ~(PF_SUPERPRIV | PF_WQ_WORKER | PF_IDLE | PF_NO_SETAFFINITY); |
514ddb44 | 2047 | p->flags |= PF_FORKNOEXEC; |
1da177e4 LT |
2048 | INIT_LIST_HEAD(&p->children); |
2049 | INIT_LIST_HEAD(&p->sibling); | |
f41d911f | 2050 | rcu_copy_process(p); |
1da177e4 LT |
2051 | p->vfork_done = NULL; |
2052 | spin_lock_init(&p->alloc_lock); | |
1da177e4 | 2053 | |
1da177e4 LT |
2054 | init_sigpending(&p->pending); |
2055 | ||
64861634 | 2056 | p->utime = p->stime = p->gtime = 0; |
40565b5a | 2057 | #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME |
64861634 | 2058 | p->utimescaled = p->stimescaled = 0; |
40565b5a | 2059 | #endif |
9d7fb042 PZ |
2060 | prev_cputime_init(&p->prev_cputime); |
2061 | ||
6a61671b | 2062 | #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN |
bac5b6b6 FW |
2063 | seqcount_init(&p->vtime.seqcount); |
2064 | p->vtime.starttime = 0; | |
2065 | p->vtime.state = VTIME_INACTIVE; | |
6a61671b FW |
2066 | #endif |
2067 | ||
0f212204 JA |
2068 | #ifdef CONFIG_IO_URING |
2069 | p->io_uring = NULL; | |
2070 | #endif | |
2071 | ||
a3a2e76c KH |
2072 | #if defined(SPLIT_RSS_COUNTING) |
2073 | memset(&p->rss_stat, 0, sizeof(p->rss_stat)); | |
2074 | #endif | |
172ba844 | 2075 | |
6976675d AV |
2076 | p->default_timer_slack_ns = current->timer_slack_ns; |
2077 | ||
eb414681 JW |
2078 | #ifdef CONFIG_PSI |
2079 | p->psi_flags = 0; | |
2080 | #endif | |
2081 | ||
5995477a | 2082 | task_io_accounting_init(&p->ioac); |
1da177e4 LT |
2083 | acct_clear_integrals(p); |
2084 | ||
3a245c0f | 2085 | posix_cputimers_init(&p->posix_cputimers); |
1da177e4 | 2086 | |
1da177e4 | 2087 | p->io_context = NULL; |
c0b0ae8a | 2088 | audit_set_context(p, NULL); |
b4f48b63 | 2089 | cgroup_fork(p); |
40966e31 EB |
2090 | if (p->flags & PF_KTHREAD) { |
2091 | if (!set_kthread_struct(p)) | |
ff8288ff | 2092 | goto bad_fork_cleanup_delayacct; |
40966e31 | 2093 | } |
1da177e4 | 2094 | #ifdef CONFIG_NUMA |
846a16bf | 2095 | p->mempolicy = mpol_dup(p->mempolicy); |
fb0a685c DRO |
2096 | if (IS_ERR(p->mempolicy)) { |
2097 | retval = PTR_ERR(p->mempolicy); | |
2098 | p->mempolicy = NULL; | |
ff8288ff | 2099 | goto bad_fork_cleanup_delayacct; |
fb0a685c | 2100 | } |
1da177e4 | 2101 | #endif |
778d3b0f MH |
2102 | #ifdef CONFIG_CPUSETS |
2103 | p->cpuset_mem_spread_rotor = NUMA_NO_NODE; | |
2104 | p->cpuset_slab_spread_rotor = NUMA_NO_NODE; | |
b7505861 | 2105 | seqcount_spinlock_init(&p->mems_allowed_seq, &p->alloc_lock); |
778d3b0f | 2106 | #endif |
de30a2b3 | 2107 | #ifdef CONFIG_TRACE_IRQFLAGS |
0584df9c ME |
2108 | memset(&p->irqtrace, 0, sizeof(p->irqtrace)); |
2109 | p->irqtrace.hardirq_disable_ip = _THIS_IP_; | |
2110 | p->irqtrace.softirq_enable_ip = _THIS_IP_; | |
2111 | p->softirqs_enabled = 1; | |
2112 | p->softirq_context = 0; | |
de30a2b3 | 2113 | #endif |
8bcbde54 DH |
2114 | |
2115 | p->pagefault_disabled = 0; | |
2116 | ||
fbb9ce95 | 2117 | #ifdef CONFIG_LOCKDEP |
b09be676 | 2118 | lockdep_init_task(p); |
fbb9ce95 | 2119 | #endif |
1da177e4 | 2120 | |
408894ee IM |
2121 | #ifdef CONFIG_DEBUG_MUTEXES |
2122 | p->blocked_on = NULL; /* not blocked yet */ | |
2123 | #endif | |
cafe5635 KO |
2124 | #ifdef CONFIG_BCACHE |
2125 | p->sequential_io = 0; | |
2126 | p->sequential_io_avg = 0; | |
2127 | #endif | |
a10787e6 SL |
2128 | #ifdef CONFIG_BPF_SYSCALL |
2129 | RCU_INIT_POINTER(p->bpf_storage, NULL); | |
c7603cfa | 2130 | p->bpf_ctx = NULL; |
a10787e6 | 2131 | #endif |
0f481406 | 2132 | |
3c90e6e9 | 2133 | /* Perform scheduler related setup. Assign this task to a CPU. */ |
aab03e05 DF |
2134 | retval = sched_fork(clone_flags, p); |
2135 | if (retval) | |
2136 | goto bad_fork_cleanup_policy; | |
6ab423e0 | 2137 | |
2b26f0aa | 2138 | retval = perf_event_init_task(p, clone_flags); |
6ab423e0 PZ |
2139 | if (retval) |
2140 | goto bad_fork_cleanup_policy; | |
fb0a685c DRO |
2141 | retval = audit_alloc(p); |
2142 | if (retval) | |
6c72e350 | 2143 | goto bad_fork_cleanup_perf; |
1da177e4 | 2144 | /* copy all the process information */ |
ab602f79 | 2145 | shm_init_task(p); |
e4e55b47 | 2146 | retval = security_task_alloc(p, clone_flags); |
fb0a685c | 2147 | if (retval) |
1da177e4 | 2148 | goto bad_fork_cleanup_audit; |
e4e55b47 TH |
2149 | retval = copy_semundo(clone_flags, p); |
2150 | if (retval) | |
2151 | goto bad_fork_cleanup_security; | |
fb0a685c DRO |
2152 | retval = copy_files(clone_flags, p); |
2153 | if (retval) | |
1da177e4 | 2154 | goto bad_fork_cleanup_semundo; |
fb0a685c DRO |
2155 | retval = copy_fs(clone_flags, p); |
2156 | if (retval) | |
1da177e4 | 2157 | goto bad_fork_cleanup_files; |
fb0a685c DRO |
2158 | retval = copy_sighand(clone_flags, p); |
2159 | if (retval) | |
1da177e4 | 2160 | goto bad_fork_cleanup_fs; |
fb0a685c DRO |
2161 | retval = copy_signal(clone_flags, p); |
2162 | if (retval) | |
1da177e4 | 2163 | goto bad_fork_cleanup_sighand; |
fb0a685c DRO |
2164 | retval = copy_mm(clone_flags, p); |
2165 | if (retval) | |
1da177e4 | 2166 | goto bad_fork_cleanup_signal; |
fb0a685c DRO |
2167 | retval = copy_namespaces(clone_flags, p); |
2168 | if (retval) | |
d84f4f99 | 2169 | goto bad_fork_cleanup_mm; |
fb0a685c DRO |
2170 | retval = copy_io(clone_flags, p); |
2171 | if (retval) | |
fd0928df | 2172 | goto bad_fork_cleanup_namespaces; |
714acdbd | 2173 | retval = copy_thread(clone_flags, args->stack, args->stack_size, p, args->tls); |
1da177e4 | 2174 | if (retval) |
fd0928df | 2175 | goto bad_fork_cleanup_io; |
1da177e4 | 2176 | |
afaef01c AP |
2177 | stackleak_task_init(p); |
2178 | ||
425fb2b4 | 2179 | if (pid != &init_struct_pid) { |
49cb2fc4 AR |
2180 | pid = alloc_pid(p->nsproxy->pid_ns_for_children, args->set_tid, |
2181 | args->set_tid_size); | |
35f71bc0 MH |
2182 | if (IS_ERR(pid)) { |
2183 | retval = PTR_ERR(pid); | |
0740aa5f | 2184 | goto bad_fork_cleanup_thread; |
35f71bc0 | 2185 | } |
425fb2b4 PE |
2186 | } |
2187 | ||
b3e58382 CB |
2188 | /* |
2189 | * This has to happen after we've potentially unshared the file | |
2190 | * descriptor table (so that the pidfd doesn't leak into the child | |
2191 | * if the fd table isn't shared). | |
2192 | */ | |
2193 | if (clone_flags & CLONE_PIDFD) { | |
6fd2fe49 | 2194 | retval = get_unused_fd_flags(O_RDWR | O_CLOEXEC); |
b3e58382 CB |
2195 | if (retval < 0) |
2196 | goto bad_fork_free_pid; | |
2197 | ||
2198 | pidfd = retval; | |
6fd2fe49 AV |
2199 | |
2200 | pidfile = anon_inode_getfile("[pidfd]", &pidfd_fops, pid, | |
2201 | O_RDWR | O_CLOEXEC); | |
2202 | if (IS_ERR(pidfile)) { | |
2203 | put_unused_fd(pidfd); | |
28dd29c0 | 2204 | retval = PTR_ERR(pidfile); |
6fd2fe49 AV |
2205 | goto bad_fork_free_pid; |
2206 | } | |
2207 | get_pid(pid); /* held by pidfile now */ | |
2208 | ||
7f192e3c | 2209 | retval = put_user(pidfd, args->pidfd); |
b3e58382 CB |
2210 | if (retval) |
2211 | goto bad_fork_put_pidfd; | |
2212 | } | |
2213 | ||
73c10101 JA |
2214 | #ifdef CONFIG_BLOCK |
2215 | p->plug = NULL; | |
2216 | #endif | |
ba31c1a4 TG |
2217 | futex_init_task(p); |
2218 | ||
f9a3879a GM |
2219 | /* |
2220 | * sigaltstack should be cleared when sharing the same VM | |
2221 | */ | |
2222 | if ((clone_flags & (CLONE_VM|CLONE_VFORK)) == CLONE_VM) | |
2a742138 | 2223 | sas_ss_reset(p); |
f9a3879a | 2224 | |
1da177e4 | 2225 | /* |
6580807d ON |
2226 | * Syscall tracing and stepping should be turned off in the |
2227 | * child regardless of CLONE_PTRACE. | |
1da177e4 | 2228 | */ |
6580807d | 2229 | user_disable_single_step(p); |
64c19ba2 | 2230 | clear_task_syscall_work(p, SYSCALL_TRACE); |
64eb35f7 GKB |
2231 | #if defined(CONFIG_GENERIC_ENTRY) || defined(TIF_SYSCALL_EMU) |
2232 | clear_task_syscall_work(p, SYSCALL_EMU); | |
ed75e8d5 | 2233 | #endif |
e02c9b0d | 2234 | clear_tsk_latency_tracing(p); |
1da177e4 | 2235 | |
1da177e4 | 2236 | /* ok, now we should be set up.. */ |
18c830df ON |
2237 | p->pid = pid_nr(pid); |
2238 | if (clone_flags & CLONE_THREAD) { | |
18c830df ON |
2239 | p->group_leader = current->group_leader; |
2240 | p->tgid = current->tgid; | |
2241 | } else { | |
18c830df ON |
2242 | p->group_leader = p; |
2243 | p->tgid = p->pid; | |
2244 | } | |
5f8aadd8 | 2245 | |
9d823e8f WF |
2246 | p->nr_dirtied = 0; |
2247 | p->nr_dirtied_pause = 128 >> (PAGE_SHIFT - 10); | |
83712358 | 2248 | p->dirty_paused_when = 0; |
9d823e8f | 2249 | |
bb8cbbfe | 2250 | p->pdeath_signal = 0; |
47e65328 | 2251 | INIT_LIST_HEAD(&p->thread_group); |
158e1645 | 2252 | p->task_works = NULL; |
ca7752ca | 2253 | clear_posix_cputimers_work(p); |
1da177e4 | 2254 | |
d741bf41 PZ |
2255 | #ifdef CONFIG_KRETPROBES |
2256 | p->kretprobe_instances.first = NULL; | |
2257 | #endif | |
2258 | ||
7e47682e AS |
2259 | /* |
2260 | * Ensure that the cgroup subsystem policies allow the new process to be | |
7b7b8a2c | 2261 | * forked. It should be noted that the new process's css_set can be changed |
7e47682e AS |
2262 | * between here and cgroup_post_fork() if an organisation operation is in |
2263 | * progress. | |
2264 | */ | |
ef2c41cf | 2265 | retval = cgroup_can_fork(p, args); |
7e47682e | 2266 | if (retval) |
5a5cf5cb | 2267 | goto bad_fork_put_pidfd; |
7e47682e | 2268 | |
b1e82065 PZ |
2269 | /* |
2270 | * Now that the cgroups are pinned, re-clone the parent cgroup and put | |
2271 | * the new task on the correct runqueue. All this *before* the task | |
2272 | * becomes visible. | |
2273 | * | |
2274 | * This isn't part of ->can_fork() because while the re-cloning is | |
2275 | * cgroup specific, it unconditionally needs to place the task on a | |
2276 | * runqueue. | |
2277 | */ | |
2278 | sched_cgroup_fork(p, args); | |
2279 | ||
7b558513 DH |
2280 | /* |
2281 | * From this point on we must avoid any synchronous user-space | |
2282 | * communication until we take the tasklist-lock. In particular, we do | |
2283 | * not want user-space to be able to predict the process start-time by | |
2284 | * stalling fork(2) after we recorded the start_time but before it is | |
2285 | * visible to the system. | |
2286 | */ | |
2287 | ||
2288 | p->start_time = ktime_get_ns(); | |
cf25e24d | 2289 | p->start_boottime = ktime_get_boottime_ns(); |
7b558513 | 2290 | |
18c830df ON |
2291 | /* |
2292 | * Make it visible to the rest of the system, but dont wake it up yet. | |
2293 | * Need tasklist lock for parent etc handling! | |
2294 | */ | |
1da177e4 LT |
2295 | write_lock_irq(&tasklist_lock); |
2296 | ||
1da177e4 | 2297 | /* CLONE_PARENT re-uses the old parent */ |
2d5516cb | 2298 | if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) { |
1da177e4 | 2299 | p->real_parent = current->real_parent; |
2d5516cb | 2300 | p->parent_exec_id = current->parent_exec_id; |
b4e00444 EW |
2301 | if (clone_flags & CLONE_THREAD) |
2302 | p->exit_signal = -1; | |
2303 | else | |
2304 | p->exit_signal = current->group_leader->exit_signal; | |
2d5516cb | 2305 | } else { |
1da177e4 | 2306 | p->real_parent = current; |
2d5516cb | 2307 | p->parent_exec_id = current->self_exec_id; |
b4e00444 | 2308 | p->exit_signal = args->exit_signal; |
2d5516cb | 2309 | } |
1da177e4 | 2310 | |
d83a7cb3 JP |
2311 | klp_copy_process(p); |
2312 | ||
85dd3f61 PZ |
2313 | sched_core_fork(p); |
2314 | ||
3f17da69 | 2315 | spin_lock(¤t->sighand->siglock); |
4a2c7a78 | 2316 | |
dbd95212 KC |
2317 | /* |
2318 | * Copy seccomp details explicitly here, in case they were changed | |
2319 | * before holding sighand lock. | |
2320 | */ | |
2321 | copy_seccomp(p); | |
2322 | ||
d7822b1e MD |
2323 | rseq_fork(p, clone_flags); |
2324 | ||
4ca1d3ee | 2325 | /* Don't start children in a dying pid namespace */ |
e8cfbc24 | 2326 | if (unlikely(!(ns_of_pid(pid)->pid_allocated & PIDNS_ADDING))) { |
3fd37226 KT |
2327 | retval = -ENOMEM; |
2328 | goto bad_fork_cancel_cgroup; | |
2329 | } | |
4a2c7a78 | 2330 | |
7673bf55 EB |
2331 | /* Let kill terminate clone/fork in the middle */ |
2332 | if (fatal_signal_pending(current)) { | |
2333 | retval = -EINTR; | |
2334 | goto bad_fork_cancel_cgroup; | |
2335 | } | |
2336 | ||
2c470475 | 2337 | init_task_pid_links(p); |
73b9ebfe | 2338 | if (likely(p->pid)) { |
4b9d33e6 | 2339 | ptrace_init_task(p, (clone_flags & CLONE_PTRACE) || trace); |
73b9ebfe | 2340 | |
81907739 | 2341 | init_task_pid(p, PIDTYPE_PID, pid); |
73b9ebfe | 2342 | if (thread_group_leader(p)) { |
6883f81a | 2343 | init_task_pid(p, PIDTYPE_TGID, pid); |
81907739 ON |
2344 | init_task_pid(p, PIDTYPE_PGID, task_pgrp(current)); |
2345 | init_task_pid(p, PIDTYPE_SID, task_session(current)); | |
2346 | ||
1c4042c2 | 2347 | if (is_child_reaper(pid)) { |
17cf22c3 | 2348 | ns_of_pid(pid)->child_reaper = p; |
1c4042c2 EB |
2349 | p->signal->flags |= SIGNAL_UNKILLABLE; |
2350 | } | |
c3ad2c3b | 2351 | p->signal->shared_pending.signal = delayed.signal; |
9c9f4ded | 2352 | p->signal->tty = tty_kref_get(current->signal->tty); |
749860ce PT |
2353 | /* |
2354 | * Inherit has_child_subreaper flag under the same | |
2355 | * tasklist_lock with adding child to the process tree | |
2356 | * for propagate_has_child_subreaper optimization. | |
2357 | */ | |
2358 | p->signal->has_child_subreaper = p->real_parent->signal->has_child_subreaper || | |
2359 | p->real_parent->signal->is_child_subreaper; | |
9cd80bbb | 2360 | list_add_tail(&p->sibling, &p->real_parent->children); |
5e85d4ab | 2361 | list_add_tail_rcu(&p->tasks, &init_task.tasks); |
6883f81a | 2362 | attach_pid(p, PIDTYPE_TGID); |
81907739 ON |
2363 | attach_pid(p, PIDTYPE_PGID); |
2364 | attach_pid(p, PIDTYPE_SID); | |
909ea964 | 2365 | __this_cpu_inc(process_counts); |
80628ca0 ON |
2366 | } else { |
2367 | current->signal->nr_threads++; | |
2368 | atomic_inc(¤t->signal->live); | |
60d4de3f | 2369 | refcount_inc(¤t->signal->sigcnt); |
924de3b8 | 2370 | task_join_group_stop(p); |
80628ca0 ON |
2371 | list_add_tail_rcu(&p->thread_group, |
2372 | &p->group_leader->thread_group); | |
0c740d0a ON |
2373 | list_add_tail_rcu(&p->thread_node, |
2374 | &p->signal->thread_head); | |
73b9ebfe | 2375 | } |
81907739 | 2376 | attach_pid(p, PIDTYPE_PID); |
73b9ebfe | 2377 | nr_threads++; |
1da177e4 | 2378 | } |
1da177e4 | 2379 | total_forks++; |
c3ad2c3b | 2380 | hlist_del_init(&delayed.node); |
3f17da69 | 2381 | spin_unlock(¤t->sighand->siglock); |
4af4206b | 2382 | syscall_tracepoint_update(p); |
1da177e4 | 2383 | write_unlock_irq(&tasklist_lock); |
4af4206b | 2384 | |
ddc204b5 WL |
2385 | if (pidfile) |
2386 | fd_install(pidfd, pidfile); | |
2387 | ||
c13cf856 | 2388 | proc_fork_connector(p); |
b1e82065 | 2389 | sched_post_fork(p); |
ef2c41cf | 2390 | cgroup_post_fork(p, args); |
cdd6c482 | 2391 | perf_event_fork(p); |
43d2b113 KH |
2392 | |
2393 | trace_task_newtask(p, clone_flags); | |
3ab67966 | 2394 | uprobe_copy_process(p, clone_flags); |
43d2b113 | 2395 | |
67197a4f SB |
2396 | copy_oom_score_adj(clone_flags, p); |
2397 | ||
1da177e4 LT |
2398 | return p; |
2399 | ||
7e47682e | 2400 | bad_fork_cancel_cgroup: |
85dd3f61 | 2401 | sched_core_free(p); |
3fd37226 KT |
2402 | spin_unlock(¤t->sighand->siglock); |
2403 | write_unlock_irq(&tasklist_lock); | |
ef2c41cf | 2404 | cgroup_cancel_fork(p, args); |
b3e58382 | 2405 | bad_fork_put_pidfd: |
6fd2fe49 AV |
2406 | if (clone_flags & CLONE_PIDFD) { |
2407 | fput(pidfile); | |
2408 | put_unused_fd(pidfd); | |
2409 | } | |
425fb2b4 PE |
2410 | bad_fork_free_pid: |
2411 | if (pid != &init_struct_pid) | |
2412 | free_pid(pid); | |
0740aa5f JS |
2413 | bad_fork_cleanup_thread: |
2414 | exit_thread(p); | |
fd0928df | 2415 | bad_fork_cleanup_io: |
b69f2292 LR |
2416 | if (p->io_context) |
2417 | exit_io_context(p); | |
ab516013 | 2418 | bad_fork_cleanup_namespaces: |
444f378b | 2419 | exit_task_namespaces(p); |
1da177e4 | 2420 | bad_fork_cleanup_mm: |
c3f3ce04 AA |
2421 | if (p->mm) { |
2422 | mm_clear_owner(p->mm, p); | |
1da177e4 | 2423 | mmput(p->mm); |
c3f3ce04 | 2424 | } |
1da177e4 | 2425 | bad_fork_cleanup_signal: |
4ab6c083 | 2426 | if (!(clone_flags & CLONE_THREAD)) |
1c5354de | 2427 | free_signal_struct(p->signal); |
1da177e4 | 2428 | bad_fork_cleanup_sighand: |
a7e5328a | 2429 | __cleanup_sighand(p->sighand); |
1da177e4 LT |
2430 | bad_fork_cleanup_fs: |
2431 | exit_fs(p); /* blocking */ | |
2432 | bad_fork_cleanup_files: | |
2433 | exit_files(p); /* blocking */ | |
2434 | bad_fork_cleanup_semundo: | |
2435 | exit_sem(p); | |
e4e55b47 TH |
2436 | bad_fork_cleanup_security: |
2437 | security_task_free(p); | |
1da177e4 LT |
2438 | bad_fork_cleanup_audit: |
2439 | audit_free(p); | |
6c72e350 | 2440 | bad_fork_cleanup_perf: |
cdd6c482 | 2441 | perf_event_free_task(p); |
6c72e350 | 2442 | bad_fork_cleanup_policy: |
b09be676 | 2443 | lockdep_free_task(p); |
1da177e4 | 2444 | #ifdef CONFIG_NUMA |
f0be3d32 | 2445 | mpol_put(p->mempolicy); |
1da177e4 | 2446 | #endif |
ff8288ff | 2447 | bad_fork_cleanup_delayacct: |
35df17c5 | 2448 | delayacct_tsk_free(p); |
1da177e4 | 2449 | bad_fork_cleanup_count: |
21d1c5e3 | 2450 | dec_rlimit_ucounts(task_ucounts(p), UCOUNT_RLIMIT_NPROC, 1); |
e0e81739 | 2451 | exit_creds(p); |
1da177e4 | 2452 | bad_fork_free: |
2f064a59 | 2453 | WRITE_ONCE(p->__state, TASK_DEAD); |
68f24b08 | 2454 | put_task_stack(p); |
c3f3ce04 | 2455 | delayed_free_task(p); |
fe7d37d1 | 2456 | fork_out: |
c3ad2c3b EB |
2457 | spin_lock_irq(¤t->sighand->siglock); |
2458 | hlist_del_init(&delayed.node); | |
2459 | spin_unlock_irq(¤t->sighand->siglock); | |
fe7d37d1 | 2460 | return ERR_PTR(retval); |
1da177e4 LT |
2461 | } |
2462 | ||
2c470475 | 2463 | static inline void init_idle_pids(struct task_struct *idle) |
f106eee1 ON |
2464 | { |
2465 | enum pid_type type; | |
2466 | ||
2467 | for (type = PIDTYPE_PID; type < PIDTYPE_MAX; ++type) { | |
2c470475 EB |
2468 | INIT_HLIST_NODE(&idle->pid_links[type]); /* not really needed */ |
2469 | init_task_pid(idle, type, &init_struct_pid); | |
f106eee1 ON |
2470 | } |
2471 | } | |
2472 | ||
f1a0a376 | 2473 | struct task_struct * __init fork_idle(int cpu) |
1da177e4 | 2474 | { |
36c8b586 | 2475 | struct task_struct *task; |
7f192e3c CB |
2476 | struct kernel_clone_args args = { |
2477 | .flags = CLONE_VM, | |
2478 | }; | |
2479 | ||
2480 | task = copy_process(&init_struct_pid, 0, cpu_to_node(cpu), &args); | |
f106eee1 | 2481 | if (!IS_ERR(task)) { |
2c470475 | 2482 | init_idle_pids(task); |
753ca4f3 | 2483 | init_idle(task, cpu); |
f106eee1 | 2484 | } |
73b9ebfe | 2485 | |
1da177e4 LT |
2486 | return task; |
2487 | } | |
2488 | ||
13585fa0 NA |
2489 | struct mm_struct *copy_init_mm(void) |
2490 | { | |
2491 | return dup_mm(NULL, &init_mm); | |
2492 | } | |
2493 | ||
cc440e87 JA |
2494 | /* |
2495 | * This is like kernel_clone(), but shaved down and tailored to just | |
2496 | * creating io_uring workers. It returns a created task, or an error pointer. | |
2497 | * The returned task is inactive, and the caller must fire it up through | |
2498 | * wake_up_new_task(p). All signals are blocked in the created task. | |
2499 | */ | |
2500 | struct task_struct *create_io_thread(int (*fn)(void *), void *arg, int node) | |
2501 | { | |
2502 | unsigned long flags = CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD| | |
2503 | CLONE_IO; | |
2504 | struct kernel_clone_args args = { | |
2505 | .flags = ((lower_32_bits(flags) | CLONE_VM | | |
2506 | CLONE_UNTRACED) & ~CSIGNAL), | |
2507 | .exit_signal = (lower_32_bits(flags) & CSIGNAL), | |
2508 | .stack = (unsigned long)fn, | |
2509 | .stack_size = (unsigned long)arg, | |
2510 | .io_thread = 1, | |
2511 | }; | |
cc440e87 | 2512 | |
b16b3855 | 2513 | return copy_process(NULL, 0, node, &args); |
cc440e87 JA |
2514 | } |
2515 | ||
1da177e4 LT |
2516 | /* |
2517 | * Ok, this is the main fork-routine. | |
2518 | * | |
2519 | * It copies the process, and if successful kick-starts | |
2520 | * it and waits for it to finish using the VM if required. | |
a0eb9abd ES |
2521 | * |
2522 | * args->exit_signal is expected to be checked for sanity by the caller. | |
1da177e4 | 2523 | */ |
cad6967a | 2524 | pid_t kernel_clone(struct kernel_clone_args *args) |
1da177e4 | 2525 | { |
7f192e3c | 2526 | u64 clone_flags = args->flags; |
9f5325aa MPS |
2527 | struct completion vfork; |
2528 | struct pid *pid; | |
1da177e4 LT |
2529 | struct task_struct *p; |
2530 | int trace = 0; | |
cad6967a | 2531 | pid_t nr; |
1da177e4 | 2532 | |
3af8588c CB |
2533 | /* |
2534 | * For legacy clone() calls, CLONE_PIDFD uses the parent_tid argument | |
2535 | * to return the pidfd. Hence, CLONE_PIDFD and CLONE_PARENT_SETTID are | |
2536 | * mutually exclusive. With clone3() CLONE_PIDFD has grown a separate | |
2537 | * field in struct clone_args and it still doesn't make sense to have | |
2538 | * them both point at the same memory location. Performing this check | |
2539 | * here has the advantage that we don't need to have a separate helper | |
2540 | * to check for legacy clone(). | |
2541 | */ | |
2542 | if ((args->flags & CLONE_PIDFD) && | |
2543 | (args->flags & CLONE_PARENT_SETTID) && | |
2544 | (args->pidfd == args->parent_tid)) | |
2545 | return -EINVAL; | |
2546 | ||
09a05394 | 2547 | /* |
4b9d33e6 TH |
2548 | * Determine whether and which event to report to ptracer. When |
2549 | * called from kernel_thread or CLONE_UNTRACED is explicitly | |
2550 | * requested, no event is reported; otherwise, report if the event | |
2551 | * for the type of forking is enabled. | |
09a05394 | 2552 | */ |
e80d6661 | 2553 | if (!(clone_flags & CLONE_UNTRACED)) { |
4b9d33e6 TH |
2554 | if (clone_flags & CLONE_VFORK) |
2555 | trace = PTRACE_EVENT_VFORK; | |
7f192e3c | 2556 | else if (args->exit_signal != SIGCHLD) |
4b9d33e6 TH |
2557 | trace = PTRACE_EVENT_CLONE; |
2558 | else | |
2559 | trace = PTRACE_EVENT_FORK; | |
2560 | ||
2561 | if (likely(!ptrace_event_enabled(current, trace))) | |
2562 | trace = 0; | |
2563 | } | |
1da177e4 | 2564 | |
7f192e3c | 2565 | p = copy_process(NULL, trace, NUMA_NO_NODE, args); |
38addce8 | 2566 | add_latent_entropy(); |
9f5325aa MPS |
2567 | |
2568 | if (IS_ERR(p)) | |
2569 | return PTR_ERR(p); | |
2570 | ||
1da177e4 LT |
2571 | /* |
2572 | * Do this prior waking up the new thread - the thread pointer | |
2573 | * might get invalid after that point, if the thread exits quickly. | |
2574 | */ | |
9f5325aa | 2575 | trace_sched_process_fork(current, p); |
0a16b607 | 2576 | |
9f5325aa MPS |
2577 | pid = get_task_pid(p, PIDTYPE_PID); |
2578 | nr = pid_vnr(pid); | |
30e49c26 | 2579 | |
9f5325aa | 2580 | if (clone_flags & CLONE_PARENT_SETTID) |
7f192e3c | 2581 | put_user(nr, args->parent_tid); |
a6f5e063 | 2582 | |
9f5325aa MPS |
2583 | if (clone_flags & CLONE_VFORK) { |
2584 | p->vfork_done = &vfork; | |
2585 | init_completion(&vfork); | |
2586 | get_task_struct(p); | |
2587 | } | |
1da177e4 | 2588 | |
9f5325aa | 2589 | wake_up_new_task(p); |
09a05394 | 2590 | |
9f5325aa MPS |
2591 | /* forking complete and child started to run, tell ptracer */ |
2592 | if (unlikely(trace)) | |
2593 | ptrace_event_pid(trace, pid); | |
4e52365f | 2594 | |
9f5325aa MPS |
2595 | if (clone_flags & CLONE_VFORK) { |
2596 | if (!wait_for_vfork_done(p, &vfork)) | |
2597 | ptrace_event_pid(PTRACE_EVENT_VFORK_DONE, pid); | |
1da177e4 | 2598 | } |
9f5325aa MPS |
2599 | |
2600 | put_pid(pid); | |
92476d7f | 2601 | return nr; |
1da177e4 LT |
2602 | } |
2603 | ||
2aa3a7f8 AV |
2604 | /* |
2605 | * Create a kernel thread. | |
2606 | */ | |
2607 | pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags) | |
2608 | { | |
7f192e3c | 2609 | struct kernel_clone_args args = { |
3f2c788a CB |
2610 | .flags = ((lower_32_bits(flags) | CLONE_VM | |
2611 | CLONE_UNTRACED) & ~CSIGNAL), | |
2612 | .exit_signal = (lower_32_bits(flags) & CSIGNAL), | |
7f192e3c CB |
2613 | .stack = (unsigned long)fn, |
2614 | .stack_size = (unsigned long)arg, | |
2615 | }; | |
2616 | ||
cad6967a | 2617 | return kernel_clone(&args); |
2aa3a7f8 | 2618 | } |
2aa3a7f8 | 2619 | |
d2125043 AV |
2620 | #ifdef __ARCH_WANT_SYS_FORK |
2621 | SYSCALL_DEFINE0(fork) | |
2622 | { | |
2623 | #ifdef CONFIG_MMU | |
7f192e3c CB |
2624 | struct kernel_clone_args args = { |
2625 | .exit_signal = SIGCHLD, | |
2626 | }; | |
2627 | ||
cad6967a | 2628 | return kernel_clone(&args); |
d2125043 AV |
2629 | #else |
2630 | /* can not support in nommu mode */ | |
5d59e182 | 2631 | return -EINVAL; |
d2125043 AV |
2632 | #endif |
2633 | } | |
2634 | #endif | |
2635 | ||
2636 | #ifdef __ARCH_WANT_SYS_VFORK | |
2637 | SYSCALL_DEFINE0(vfork) | |
2638 | { | |
7f192e3c CB |
2639 | struct kernel_clone_args args = { |
2640 | .flags = CLONE_VFORK | CLONE_VM, | |
2641 | .exit_signal = SIGCHLD, | |
2642 | }; | |
2643 | ||
cad6967a | 2644 | return kernel_clone(&args); |
d2125043 AV |
2645 | } |
2646 | #endif | |
2647 | ||
2648 | #ifdef __ARCH_WANT_SYS_CLONE | |
2649 | #ifdef CONFIG_CLONE_BACKWARDS | |
2650 | SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp, | |
2651 | int __user *, parent_tidptr, | |
3033f14a | 2652 | unsigned long, tls, |
d2125043 AV |
2653 | int __user *, child_tidptr) |
2654 | #elif defined(CONFIG_CLONE_BACKWARDS2) | |
2655 | SYSCALL_DEFINE5(clone, unsigned long, newsp, unsigned long, clone_flags, | |
2656 | int __user *, parent_tidptr, | |
2657 | int __user *, child_tidptr, | |
3033f14a | 2658 | unsigned long, tls) |
dfa9771a MS |
2659 | #elif defined(CONFIG_CLONE_BACKWARDS3) |
2660 | SYSCALL_DEFINE6(clone, unsigned long, clone_flags, unsigned long, newsp, | |
2661 | int, stack_size, | |
2662 | int __user *, parent_tidptr, | |
2663 | int __user *, child_tidptr, | |
3033f14a | 2664 | unsigned long, tls) |
d2125043 AV |
2665 | #else |
2666 | SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp, | |
2667 | int __user *, parent_tidptr, | |
2668 | int __user *, child_tidptr, | |
3033f14a | 2669 | unsigned long, tls) |
d2125043 AV |
2670 | #endif |
2671 | { | |
7f192e3c | 2672 | struct kernel_clone_args args = { |
3f2c788a | 2673 | .flags = (lower_32_bits(clone_flags) & ~CSIGNAL), |
7f192e3c CB |
2674 | .pidfd = parent_tidptr, |
2675 | .child_tid = child_tidptr, | |
2676 | .parent_tid = parent_tidptr, | |
3f2c788a | 2677 | .exit_signal = (lower_32_bits(clone_flags) & CSIGNAL), |
7f192e3c CB |
2678 | .stack = newsp, |
2679 | .tls = tls, | |
2680 | }; | |
2681 | ||
cad6967a | 2682 | return kernel_clone(&args); |
7f192e3c | 2683 | } |
d68dbb0c | 2684 | #endif |
7f192e3c | 2685 | |
d68dbb0c | 2686 | #ifdef __ARCH_WANT_SYS_CLONE3 |
dd499f7a | 2687 | |
7f192e3c CB |
2688 | noinline static int copy_clone_args_from_user(struct kernel_clone_args *kargs, |
2689 | struct clone_args __user *uargs, | |
f14c234b | 2690 | size_t usize) |
7f192e3c | 2691 | { |
f14c234b | 2692 | int err; |
7f192e3c | 2693 | struct clone_args args; |
49cb2fc4 | 2694 | pid_t *kset_tid = kargs->set_tid; |
7f192e3c | 2695 | |
a966dcfe ES |
2696 | BUILD_BUG_ON(offsetofend(struct clone_args, tls) != |
2697 | CLONE_ARGS_SIZE_VER0); | |
2698 | BUILD_BUG_ON(offsetofend(struct clone_args, set_tid_size) != | |
2699 | CLONE_ARGS_SIZE_VER1); | |
2700 | BUILD_BUG_ON(offsetofend(struct clone_args, cgroup) != | |
2701 | CLONE_ARGS_SIZE_VER2); | |
2702 | BUILD_BUG_ON(sizeof(struct clone_args) != CLONE_ARGS_SIZE_VER2); | |
2703 | ||
f14c234b | 2704 | if (unlikely(usize > PAGE_SIZE)) |
7f192e3c | 2705 | return -E2BIG; |
f14c234b | 2706 | if (unlikely(usize < CLONE_ARGS_SIZE_VER0)) |
7f192e3c CB |
2707 | return -EINVAL; |
2708 | ||
f14c234b AS |
2709 | err = copy_struct_from_user(&args, sizeof(args), uargs, usize); |
2710 | if (err) | |
2711 | return err; | |
7f192e3c | 2712 | |
49cb2fc4 AR |
2713 | if (unlikely(args.set_tid_size > MAX_PID_NS_LEVEL)) |
2714 | return -EINVAL; | |
2715 | ||
2716 | if (unlikely(!args.set_tid && args.set_tid_size > 0)) | |
2717 | return -EINVAL; | |
2718 | ||
2719 | if (unlikely(args.set_tid && args.set_tid_size == 0)) | |
2720 | return -EINVAL; | |
2721 | ||
a0eb9abd ES |
2722 | /* |
2723 | * Verify that higher 32bits of exit_signal are unset and that | |
2724 | * it is a valid signal | |
2725 | */ | |
2726 | if (unlikely((args.exit_signal & ~((u64)CSIGNAL)) || | |
2727 | !valid_signal(args.exit_signal))) | |
2728 | return -EINVAL; | |
2729 | ||
62173872 ES |
2730 | if ((args.flags & CLONE_INTO_CGROUP) && |
2731 | (args.cgroup > INT_MAX || usize < CLONE_ARGS_SIZE_VER2)) | |
ef2c41cf CB |
2732 | return -EINVAL; |
2733 | ||
7f192e3c CB |
2734 | *kargs = (struct kernel_clone_args){ |
2735 | .flags = args.flags, | |
2736 | .pidfd = u64_to_user_ptr(args.pidfd), | |
2737 | .child_tid = u64_to_user_ptr(args.child_tid), | |
2738 | .parent_tid = u64_to_user_ptr(args.parent_tid), | |
2739 | .exit_signal = args.exit_signal, | |
2740 | .stack = args.stack, | |
2741 | .stack_size = args.stack_size, | |
2742 | .tls = args.tls, | |
49cb2fc4 | 2743 | .set_tid_size = args.set_tid_size, |
ef2c41cf | 2744 | .cgroup = args.cgroup, |
7f192e3c CB |
2745 | }; |
2746 | ||
49cb2fc4 AR |
2747 | if (args.set_tid && |
2748 | copy_from_user(kset_tid, u64_to_user_ptr(args.set_tid), | |
2749 | (kargs->set_tid_size * sizeof(pid_t)))) | |
2750 | return -EFAULT; | |
2751 | ||
2752 | kargs->set_tid = kset_tid; | |
2753 | ||
7f192e3c CB |
2754 | return 0; |
2755 | } | |
2756 | ||
fa729c4d CB |
2757 | /** |
2758 | * clone3_stack_valid - check and prepare stack | |
2759 | * @kargs: kernel clone args | |
2760 | * | |
2761 | * Verify that the stack arguments userspace gave us are sane. | |
2762 | * In addition, set the stack direction for userspace since it's easy for us to | |
2763 | * determine. | |
2764 | */ | |
2765 | static inline bool clone3_stack_valid(struct kernel_clone_args *kargs) | |
2766 | { | |
2767 | if (kargs->stack == 0) { | |
2768 | if (kargs->stack_size > 0) | |
2769 | return false; | |
2770 | } else { | |
2771 | if (kargs->stack_size == 0) | |
2772 | return false; | |
2773 | ||
2774 | if (!access_ok((void __user *)kargs->stack, kargs->stack_size)) | |
2775 | return false; | |
2776 | ||
2777 | #if !defined(CONFIG_STACK_GROWSUP) && !defined(CONFIG_IA64) | |
2778 | kargs->stack += kargs->stack_size; | |
2779 | #endif | |
2780 | } | |
2781 | ||
2782 | return true; | |
2783 | } | |
2784 | ||
2785 | static bool clone3_args_valid(struct kernel_clone_args *kargs) | |
7f192e3c | 2786 | { |
b612e5df | 2787 | /* Verify that no unknown flags are passed along. */ |
ef2c41cf CB |
2788 | if (kargs->flags & |
2789 | ~(CLONE_LEGACY_FLAGS | CLONE_CLEAR_SIGHAND | CLONE_INTO_CGROUP)) | |
7f192e3c CB |
2790 | return false; |
2791 | ||
2792 | /* | |
a8ca6b13 XC |
2793 | * - make the CLONE_DETACHED bit reusable for clone3 |
2794 | * - make the CSIGNAL bits reusable for clone3 | |
7f192e3c CB |
2795 | */ |
2796 | if (kargs->flags & (CLONE_DETACHED | CSIGNAL)) | |
2797 | return false; | |
2798 | ||
b612e5df CB |
2799 | if ((kargs->flags & (CLONE_SIGHAND | CLONE_CLEAR_SIGHAND)) == |
2800 | (CLONE_SIGHAND | CLONE_CLEAR_SIGHAND)) | |
2801 | return false; | |
2802 | ||
7f192e3c CB |
2803 | if ((kargs->flags & (CLONE_THREAD | CLONE_PARENT)) && |
2804 | kargs->exit_signal) | |
2805 | return false; | |
2806 | ||
fa729c4d CB |
2807 | if (!clone3_stack_valid(kargs)) |
2808 | return false; | |
2809 | ||
7f192e3c CB |
2810 | return true; |
2811 | } | |
2812 | ||
501bd016 CB |
2813 | /** |
2814 | * clone3 - create a new process with specific properties | |
2815 | * @uargs: argument structure | |
2816 | * @size: size of @uargs | |
2817 | * | |
2818 | * clone3() is the extensible successor to clone()/clone2(). | |
2819 | * It takes a struct as argument that is versioned by its size. | |
2820 | * | |
2821 | * Return: On success, a positive PID for the child process. | |
2822 | * On error, a negative errno number. | |
2823 | */ | |
7f192e3c CB |
2824 | SYSCALL_DEFINE2(clone3, struct clone_args __user *, uargs, size_t, size) |
2825 | { | |
2826 | int err; | |
2827 | ||
2828 | struct kernel_clone_args kargs; | |
49cb2fc4 AR |
2829 | pid_t set_tid[MAX_PID_NS_LEVEL]; |
2830 | ||
2831 | kargs.set_tid = set_tid; | |
7f192e3c CB |
2832 | |
2833 | err = copy_clone_args_from_user(&kargs, uargs, size); | |
2834 | if (err) | |
2835 | return err; | |
2836 | ||
2837 | if (!clone3_args_valid(&kargs)) | |
2838 | return -EINVAL; | |
2839 | ||
cad6967a | 2840 | return kernel_clone(&kargs); |
d2125043 AV |
2841 | } |
2842 | #endif | |
2843 | ||
0f1b92cb ON |
2844 | void walk_process_tree(struct task_struct *top, proc_visitor visitor, void *data) |
2845 | { | |
2846 | struct task_struct *leader, *parent, *child; | |
2847 | int res; | |
2848 | ||
2849 | read_lock(&tasklist_lock); | |
2850 | leader = top = top->group_leader; | |
2851 | down: | |
2852 | for_each_thread(leader, parent) { | |
2853 | list_for_each_entry(child, &parent->children, sibling) { | |
2854 | res = visitor(child, data); | |
2855 | if (res) { | |
2856 | if (res < 0) | |
2857 | goto out; | |
2858 | leader = child; | |
2859 | goto down; | |
2860 | } | |
2861 | up: | |
2862 | ; | |
2863 | } | |
2864 | } | |
2865 | ||
2866 | if (leader != top) { | |
2867 | child = leader; | |
2868 | parent = child->real_parent; | |
2869 | leader = parent->group_leader; | |
2870 | goto up; | |
2871 | } | |
2872 | out: | |
2873 | read_unlock(&tasklist_lock); | |
2874 | } | |
2875 | ||
5fd63b30 RT |
2876 | #ifndef ARCH_MIN_MMSTRUCT_ALIGN |
2877 | #define ARCH_MIN_MMSTRUCT_ALIGN 0 | |
2878 | #endif | |
2879 | ||
51cc5068 | 2880 | static void sighand_ctor(void *data) |
aa1757f9 ON |
2881 | { |
2882 | struct sighand_struct *sighand = data; | |
2883 | ||
a35afb83 | 2884 | spin_lock_init(&sighand->siglock); |
b8fceee1 | 2885 | init_waitqueue_head(&sighand->signalfd_wqh); |
aa1757f9 ON |
2886 | } |
2887 | ||
1da177e4 LT |
2888 | void __init proc_caches_init(void) |
2889 | { | |
c1a2f7f0 RR |
2890 | unsigned int mm_size; |
2891 | ||
1da177e4 LT |
2892 | sighand_cachep = kmem_cache_create("sighand_cache", |
2893 | sizeof(struct sighand_struct), 0, | |
5f0d5a3a | 2894 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_TYPESAFE_BY_RCU| |
75f296d9 | 2895 | SLAB_ACCOUNT, sighand_ctor); |
1da177e4 LT |
2896 | signal_cachep = kmem_cache_create("signal_cache", |
2897 | sizeof(struct signal_struct), 0, | |
75f296d9 | 2898 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT, |
5d097056 | 2899 | NULL); |
20c2df83 | 2900 | files_cachep = kmem_cache_create("files_cache", |
1da177e4 | 2901 | sizeof(struct files_struct), 0, |
75f296d9 | 2902 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT, |
5d097056 | 2903 | NULL); |
20c2df83 | 2904 | fs_cachep = kmem_cache_create("fs_cache", |
1da177e4 | 2905 | sizeof(struct fs_struct), 0, |
75f296d9 | 2906 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT, |
5d097056 | 2907 | NULL); |
c1a2f7f0 | 2908 | |
6345d24d | 2909 | /* |
c1a2f7f0 RR |
2910 | * The mm_cpumask is located at the end of mm_struct, and is |
2911 | * dynamically sized based on the maximum CPU number this system | |
2912 | * can have, taking hotplug into account (nr_cpu_ids). | |
6345d24d | 2913 | */ |
c1a2f7f0 RR |
2914 | mm_size = sizeof(struct mm_struct) + cpumask_size(); |
2915 | ||
07dcd7fe | 2916 | mm_cachep = kmem_cache_create_usercopy("mm_struct", |
c1a2f7f0 | 2917 | mm_size, ARCH_MIN_MMSTRUCT_ALIGN, |
75f296d9 | 2918 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT, |
07dcd7fe DW |
2919 | offsetof(struct mm_struct, saved_auxv), |
2920 | sizeof_field(struct mm_struct, saved_auxv), | |
5d097056 VD |
2921 | NULL); |
2922 | vm_area_cachep = KMEM_CACHE(vm_area_struct, SLAB_PANIC|SLAB_ACCOUNT); | |
8feae131 | 2923 | mmap_init(); |
66577193 | 2924 | nsproxy_cache_init(); |
1da177e4 | 2925 | } |
cf2e340f | 2926 | |
cf2e340f | 2927 | /* |
9bfb23fc | 2928 | * Check constraints on flags passed to the unshare system call. |
cf2e340f | 2929 | */ |
9bfb23fc | 2930 | static int check_unshare_flags(unsigned long unshare_flags) |
cf2e340f | 2931 | { |
9bfb23fc ON |
2932 | if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND| |
2933 | CLONE_VM|CLONE_FILES|CLONE_SYSVSEM| | |
50804fe3 | 2934 | CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWNET| |
769071ac AV |
2935 | CLONE_NEWUSER|CLONE_NEWPID|CLONE_NEWCGROUP| |
2936 | CLONE_NEWTIME)) | |
9bfb23fc | 2937 | return -EINVAL; |
cf2e340f | 2938 | /* |
12c641ab EB |
2939 | * Not implemented, but pretend it works if there is nothing |
2940 | * to unshare. Note that unsharing the address space or the | |
2941 | * signal handlers also need to unshare the signal queues (aka | |
2942 | * CLONE_THREAD). | |
cf2e340f | 2943 | */ |
9bfb23fc | 2944 | if (unshare_flags & (CLONE_THREAD | CLONE_SIGHAND | CLONE_VM)) { |
12c641ab EB |
2945 | if (!thread_group_empty(current)) |
2946 | return -EINVAL; | |
2947 | } | |
2948 | if (unshare_flags & (CLONE_SIGHAND | CLONE_VM)) { | |
d036bda7 | 2949 | if (refcount_read(¤t->sighand->count) > 1) |
12c641ab EB |
2950 | return -EINVAL; |
2951 | } | |
2952 | if (unshare_flags & CLONE_VM) { | |
2953 | if (!current_is_single_threaded()) | |
9bfb23fc ON |
2954 | return -EINVAL; |
2955 | } | |
cf2e340f JD |
2956 | |
2957 | return 0; | |
2958 | } | |
2959 | ||
2960 | /* | |
99d1419d | 2961 | * Unshare the filesystem structure if it is being shared |
cf2e340f JD |
2962 | */ |
2963 | static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp) | |
2964 | { | |
2965 | struct fs_struct *fs = current->fs; | |
2966 | ||
498052bb AV |
2967 | if (!(unshare_flags & CLONE_FS) || !fs) |
2968 | return 0; | |
2969 | ||
2970 | /* don't need lock here; in the worst case we'll do useless copy */ | |
2971 | if (fs->users == 1) | |
2972 | return 0; | |
2973 | ||
2974 | *new_fsp = copy_fs_struct(fs); | |
2975 | if (!*new_fsp) | |
2976 | return -ENOMEM; | |
cf2e340f JD |
2977 | |
2978 | return 0; | |
2979 | } | |
2980 | ||
cf2e340f | 2981 | /* |
a016f338 | 2982 | * Unshare file descriptor table if it is being shared |
cf2e340f | 2983 | */ |
60997c3d CB |
2984 | int unshare_fd(unsigned long unshare_flags, unsigned int max_fds, |
2985 | struct files_struct **new_fdp) | |
cf2e340f JD |
2986 | { |
2987 | struct files_struct *fd = current->files; | |
a016f338 | 2988 | int error = 0; |
cf2e340f JD |
2989 | |
2990 | if ((unshare_flags & CLONE_FILES) && | |
a016f338 | 2991 | (fd && atomic_read(&fd->count) > 1)) { |
60997c3d | 2992 | *new_fdp = dup_fd(fd, max_fds, &error); |
a016f338 JD |
2993 | if (!*new_fdp) |
2994 | return error; | |
2995 | } | |
cf2e340f JD |
2996 | |
2997 | return 0; | |
2998 | } | |
2999 | ||
cf2e340f JD |
3000 | /* |
3001 | * unshare allows a process to 'unshare' part of the process | |
3002 | * context which was originally shared using clone. copy_* | |
cad6967a | 3003 | * functions used by kernel_clone() cannot be used here directly |
cf2e340f JD |
3004 | * because they modify an inactive task_struct that is being |
3005 | * constructed. Here we are modifying the current, active, | |
3006 | * task_struct. | |
3007 | */ | |
9b32105e | 3008 | int ksys_unshare(unsigned long unshare_flags) |
cf2e340f | 3009 | { |
cf2e340f | 3010 | struct fs_struct *fs, *new_fs = NULL; |
ba1f70dd | 3011 | struct files_struct *new_fd = NULL; |
b2e0d987 | 3012 | struct cred *new_cred = NULL; |
cf7b708c | 3013 | struct nsproxy *new_nsproxy = NULL; |
9edff4ab | 3014 | int do_sysvsem = 0; |
9bfb23fc | 3015 | int err; |
cf2e340f | 3016 | |
b2e0d987 | 3017 | /* |
faf00da5 EB |
3018 | * If unsharing a user namespace must also unshare the thread group |
3019 | * and unshare the filesystem root and working directories. | |
b2e0d987 EB |
3020 | */ |
3021 | if (unshare_flags & CLONE_NEWUSER) | |
e66eded8 | 3022 | unshare_flags |= CLONE_THREAD | CLONE_FS; |
50804fe3 EB |
3023 | /* |
3024 | * If unsharing vm, must also unshare signal handlers. | |
3025 | */ | |
3026 | if (unshare_flags & CLONE_VM) | |
3027 | unshare_flags |= CLONE_SIGHAND; | |
12c641ab EB |
3028 | /* |
3029 | * If unsharing a signal handlers, must also unshare the signal queues. | |
3030 | */ | |
3031 | if (unshare_flags & CLONE_SIGHAND) | |
3032 | unshare_flags |= CLONE_THREAD; | |
9bfb23fc ON |
3033 | /* |
3034 | * If unsharing namespace, must also unshare filesystem information. | |
3035 | */ | |
3036 | if (unshare_flags & CLONE_NEWNS) | |
3037 | unshare_flags |= CLONE_FS; | |
50804fe3 EB |
3038 | |
3039 | err = check_unshare_flags(unshare_flags); | |
3040 | if (err) | |
3041 | goto bad_unshare_out; | |
6013f67f MS |
3042 | /* |
3043 | * CLONE_NEWIPC must also detach from the undolist: after switching | |
3044 | * to a new ipc namespace, the semaphore arrays from the old | |
3045 | * namespace are unreachable. | |
3046 | */ | |
3047 | if (unshare_flags & (CLONE_NEWIPC|CLONE_SYSVSEM)) | |
9edff4ab | 3048 | do_sysvsem = 1; |
fb0a685c DRO |
3049 | err = unshare_fs(unshare_flags, &new_fs); |
3050 | if (err) | |
9bfb23fc | 3051 | goto bad_unshare_out; |
60997c3d | 3052 | err = unshare_fd(unshare_flags, NR_OPEN_MAX, &new_fd); |
fb0a685c | 3053 | if (err) |
9bfb23fc | 3054 | goto bad_unshare_cleanup_fs; |
b2e0d987 | 3055 | err = unshare_userns(unshare_flags, &new_cred); |
fb0a685c | 3056 | if (err) |
9edff4ab | 3057 | goto bad_unshare_cleanup_fd; |
b2e0d987 EB |
3058 | err = unshare_nsproxy_namespaces(unshare_flags, &new_nsproxy, |
3059 | new_cred, new_fs); | |
3060 | if (err) | |
3061 | goto bad_unshare_cleanup_cred; | |
c0b2fc31 | 3062 | |
905ae01c AG |
3063 | if (new_cred) { |
3064 | err = set_cred_ucounts(new_cred); | |
3065 | if (err) | |
3066 | goto bad_unshare_cleanup_cred; | |
3067 | } | |
3068 | ||
b2e0d987 | 3069 | if (new_fs || new_fd || do_sysvsem || new_cred || new_nsproxy) { |
9edff4ab MS |
3070 | if (do_sysvsem) { |
3071 | /* | |
3072 | * CLONE_SYSVSEM is equivalent to sys_exit(). | |
3073 | */ | |
3074 | exit_sem(current); | |
3075 | } | |
ab602f79 JM |
3076 | if (unshare_flags & CLONE_NEWIPC) { |
3077 | /* Orphan segments in old ns (see sem above). */ | |
3078 | exit_shm(current); | |
3079 | shm_init_task(current); | |
3080 | } | |
ab516013 | 3081 | |
6f977e6b | 3082 | if (new_nsproxy) |
cf7b708c | 3083 | switch_task_namespaces(current, new_nsproxy); |
cf2e340f | 3084 | |
cf7b708c PE |
3085 | task_lock(current); |
3086 | ||
cf2e340f JD |
3087 | if (new_fs) { |
3088 | fs = current->fs; | |
2a4419b5 | 3089 | spin_lock(&fs->lock); |
cf2e340f | 3090 | current->fs = new_fs; |
498052bb AV |
3091 | if (--fs->users) |
3092 | new_fs = NULL; | |
3093 | else | |
3094 | new_fs = fs; | |
2a4419b5 | 3095 | spin_unlock(&fs->lock); |
cf2e340f JD |
3096 | } |
3097 | ||
ba1f70dd RX |
3098 | if (new_fd) |
3099 | swap(current->files, new_fd); | |
cf2e340f JD |
3100 | |
3101 | task_unlock(current); | |
b2e0d987 EB |
3102 | |
3103 | if (new_cred) { | |
3104 | /* Install the new user namespace */ | |
3105 | commit_creds(new_cred); | |
3106 | new_cred = NULL; | |
3107 | } | |
cf2e340f JD |
3108 | } |
3109 | ||
e4222673 HB |
3110 | perf_event_namespaces(current); |
3111 | ||
b2e0d987 EB |
3112 | bad_unshare_cleanup_cred: |
3113 | if (new_cred) | |
3114 | put_cred(new_cred); | |
cf2e340f JD |
3115 | bad_unshare_cleanup_fd: |
3116 | if (new_fd) | |
3117 | put_files_struct(new_fd); | |
3118 | ||
cf2e340f JD |
3119 | bad_unshare_cleanup_fs: |
3120 | if (new_fs) | |
498052bb | 3121 | free_fs_struct(new_fs); |
cf2e340f | 3122 | |
cf2e340f JD |
3123 | bad_unshare_out: |
3124 | return err; | |
3125 | } | |
3b125388 | 3126 | |
9b32105e DB |
3127 | SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags) |
3128 | { | |
3129 | return ksys_unshare(unshare_flags); | |
3130 | } | |
3131 | ||
3b125388 AV |
3132 | /* |
3133 | * Helper to unshare the files of the current task. | |
3134 | * We don't want to expose copy_files internals to | |
3135 | * the exec layer of the kernel. | |
3136 | */ | |
3137 | ||
1f702603 | 3138 | int unshare_files(void) |
3b125388 AV |
3139 | { |
3140 | struct task_struct *task = current; | |
1f702603 | 3141 | struct files_struct *old, *copy = NULL; |
3b125388 AV |
3142 | int error; |
3143 | ||
60997c3d | 3144 | error = unshare_fd(CLONE_FILES, NR_OPEN_MAX, ©); |
1f702603 | 3145 | if (error || !copy) |
3b125388 | 3146 | return error; |
1f702603 EB |
3147 | |
3148 | old = task->files; | |
3b125388 AV |
3149 | task_lock(task); |
3150 | task->files = copy; | |
3151 | task_unlock(task); | |
1f702603 | 3152 | put_files_struct(old); |
3b125388 AV |
3153 | return 0; |
3154 | } | |
16db3d3f HS |
3155 | |
3156 | int sysctl_max_threads(struct ctl_table *table, int write, | |
b0daa2c7 | 3157 | void *buffer, size_t *lenp, loff_t *ppos) |
16db3d3f HS |
3158 | { |
3159 | struct ctl_table t; | |
3160 | int ret; | |
3161 | int threads = max_threads; | |
b0f53dbc | 3162 | int min = 1; |
16db3d3f HS |
3163 | int max = MAX_THREADS; |
3164 | ||
3165 | t = *table; | |
3166 | t.data = &threads; | |
3167 | t.extra1 = &min; | |
3168 | t.extra2 = &max; | |
3169 | ||
3170 | ret = proc_dointvec_minmax(&t, write, buffer, lenp, ppos); | |
3171 | if (ret || !write) | |
3172 | return ret; | |
3173 | ||
b0f53dbc | 3174 | max_threads = threads; |
16db3d3f HS |
3175 | |
3176 | return 0; | |
3177 | } |