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6a46079c AK |
1 | /* |
2 | * Copyright (C) 2008, 2009 Intel Corporation | |
3 | * Authors: Andi Kleen, Fengguang Wu | |
4 | * | |
5 | * This software may be redistributed and/or modified under the terms of | |
6 | * the GNU General Public License ("GPL") version 2 only as published by the | |
7 | * Free Software Foundation. | |
8 | * | |
9 | * High level machine check handler. Handles pages reported by the | |
1c80b990 | 10 | * hardware as being corrupted usually due to a multi-bit ECC memory or cache |
6a46079c | 11 | * failure. |
1c80b990 AK |
12 | * |
13 | * In addition there is a "soft offline" entry point that allows stop using | |
14 | * not-yet-corrupted-by-suspicious pages without killing anything. | |
6a46079c AK |
15 | * |
16 | * Handles page cache pages in various states. The tricky part | |
1c80b990 AK |
17 | * here is that we can access any page asynchronously in respect to |
18 | * other VM users, because memory failures could happen anytime and | |
19 | * anywhere. This could violate some of their assumptions. This is why | |
20 | * this code has to be extremely careful. Generally it tries to use | |
21 | * normal locking rules, as in get the standard locks, even if that means | |
22 | * the error handling takes potentially a long time. | |
e0de78df AK |
23 | * |
24 | * It can be very tempting to add handling for obscure cases here. | |
25 | * In general any code for handling new cases should only be added iff: | |
26 | * - You know how to test it. | |
27 | * - You have a test that can be added to mce-test | |
28 | * https://git.kernel.org/cgit/utils/cpu/mce/mce-test.git/ | |
29 | * - The case actually shows up as a frequent (top 10) page state in | |
30 | * tools/vm/page-types when running a real workload. | |
1c80b990 AK |
31 | * |
32 | * There are several operations here with exponential complexity because | |
33 | * of unsuitable VM data structures. For example the operation to map back | |
34 | * from RMAP chains to processes has to walk the complete process list and | |
35 | * has non linear complexity with the number. But since memory corruptions | |
36 | * are rare we hope to get away with this. This avoids impacting the core | |
37 | * VM. | |
6a46079c | 38 | */ |
6a46079c AK |
39 | #include <linux/kernel.h> |
40 | #include <linux/mm.h> | |
41 | #include <linux/page-flags.h> | |
478c5ffc | 42 | #include <linux/kernel-page-flags.h> |
3f07c014 | 43 | #include <linux/sched/signal.h> |
29930025 | 44 | #include <linux/sched/task.h> |
01e00f88 | 45 | #include <linux/ksm.h> |
6a46079c | 46 | #include <linux/rmap.h> |
b9e15baf | 47 | #include <linux/export.h> |
6a46079c AK |
48 | #include <linux/pagemap.h> |
49 | #include <linux/swap.h> | |
50 | #include <linux/backing-dev.h> | |
facb6011 AK |
51 | #include <linux/migrate.h> |
52 | #include <linux/page-isolation.h> | |
53 | #include <linux/suspend.h> | |
5a0e3ad6 | 54 | #include <linux/slab.h> |
bf998156 | 55 | #include <linux/swapops.h> |
7af446a8 | 56 | #include <linux/hugetlb.h> |
20d6c96b | 57 | #include <linux/memory_hotplug.h> |
5db8a73a | 58 | #include <linux/mm_inline.h> |
ea8f5fb8 | 59 | #include <linux/kfifo.h> |
a5f65109 | 60 | #include <linux/ratelimit.h> |
6a46079c | 61 | #include "internal.h" |
97f0b134 | 62 | #include "ras/ras_event.h" |
6a46079c AK |
63 | |
64 | int sysctl_memory_failure_early_kill __read_mostly = 0; | |
65 | ||
66 | int sysctl_memory_failure_recovery __read_mostly = 1; | |
67 | ||
293c07e3 | 68 | atomic_long_t num_poisoned_pages __read_mostly = ATOMIC_LONG_INIT(0); |
6a46079c | 69 | |
27df5068 AK |
70 | #if defined(CONFIG_HWPOISON_INJECT) || defined(CONFIG_HWPOISON_INJECT_MODULE) |
71 | ||
1bfe5feb | 72 | u32 hwpoison_filter_enable = 0; |
7c116f2b WF |
73 | u32 hwpoison_filter_dev_major = ~0U; |
74 | u32 hwpoison_filter_dev_minor = ~0U; | |
478c5ffc WF |
75 | u64 hwpoison_filter_flags_mask; |
76 | u64 hwpoison_filter_flags_value; | |
1bfe5feb | 77 | EXPORT_SYMBOL_GPL(hwpoison_filter_enable); |
7c116f2b WF |
78 | EXPORT_SYMBOL_GPL(hwpoison_filter_dev_major); |
79 | EXPORT_SYMBOL_GPL(hwpoison_filter_dev_minor); | |
478c5ffc WF |
80 | EXPORT_SYMBOL_GPL(hwpoison_filter_flags_mask); |
81 | EXPORT_SYMBOL_GPL(hwpoison_filter_flags_value); | |
7c116f2b WF |
82 | |
83 | static int hwpoison_filter_dev(struct page *p) | |
84 | { | |
85 | struct address_space *mapping; | |
86 | dev_t dev; | |
87 | ||
88 | if (hwpoison_filter_dev_major == ~0U && | |
89 | hwpoison_filter_dev_minor == ~0U) | |
90 | return 0; | |
91 | ||
92 | /* | |
1c80b990 | 93 | * page_mapping() does not accept slab pages. |
7c116f2b WF |
94 | */ |
95 | if (PageSlab(p)) | |
96 | return -EINVAL; | |
97 | ||
98 | mapping = page_mapping(p); | |
99 | if (mapping == NULL || mapping->host == NULL) | |
100 | return -EINVAL; | |
101 | ||
102 | dev = mapping->host->i_sb->s_dev; | |
103 | if (hwpoison_filter_dev_major != ~0U && | |
104 | hwpoison_filter_dev_major != MAJOR(dev)) | |
105 | return -EINVAL; | |
106 | if (hwpoison_filter_dev_minor != ~0U && | |
107 | hwpoison_filter_dev_minor != MINOR(dev)) | |
108 | return -EINVAL; | |
109 | ||
110 | return 0; | |
111 | } | |
112 | ||
478c5ffc WF |
113 | static int hwpoison_filter_flags(struct page *p) |
114 | { | |
115 | if (!hwpoison_filter_flags_mask) | |
116 | return 0; | |
117 | ||
118 | if ((stable_page_flags(p) & hwpoison_filter_flags_mask) == | |
119 | hwpoison_filter_flags_value) | |
120 | return 0; | |
121 | else | |
122 | return -EINVAL; | |
123 | } | |
124 | ||
4fd466eb AK |
125 | /* |
126 | * This allows stress tests to limit test scope to a collection of tasks | |
127 | * by putting them under some memcg. This prevents killing unrelated/important | |
128 | * processes such as /sbin/init. Note that the target task may share clean | |
129 | * pages with init (eg. libc text), which is harmless. If the target task | |
130 | * share _dirty_ pages with another task B, the test scheme must make sure B | |
131 | * is also included in the memcg. At last, due to race conditions this filter | |
132 | * can only guarantee that the page either belongs to the memcg tasks, or is | |
133 | * a freed page. | |
134 | */ | |
94a59fb3 | 135 | #ifdef CONFIG_MEMCG |
4fd466eb AK |
136 | u64 hwpoison_filter_memcg; |
137 | EXPORT_SYMBOL_GPL(hwpoison_filter_memcg); | |
138 | static int hwpoison_filter_task(struct page *p) | |
139 | { | |
4fd466eb AK |
140 | if (!hwpoison_filter_memcg) |
141 | return 0; | |
142 | ||
94a59fb3 | 143 | if (page_cgroup_ino(p) != hwpoison_filter_memcg) |
4fd466eb AK |
144 | return -EINVAL; |
145 | ||
146 | return 0; | |
147 | } | |
148 | #else | |
149 | static int hwpoison_filter_task(struct page *p) { return 0; } | |
150 | #endif | |
151 | ||
7c116f2b WF |
152 | int hwpoison_filter(struct page *p) |
153 | { | |
1bfe5feb HL |
154 | if (!hwpoison_filter_enable) |
155 | return 0; | |
156 | ||
7c116f2b WF |
157 | if (hwpoison_filter_dev(p)) |
158 | return -EINVAL; | |
159 | ||
478c5ffc WF |
160 | if (hwpoison_filter_flags(p)) |
161 | return -EINVAL; | |
162 | ||
4fd466eb AK |
163 | if (hwpoison_filter_task(p)) |
164 | return -EINVAL; | |
165 | ||
7c116f2b WF |
166 | return 0; |
167 | } | |
27df5068 AK |
168 | #else |
169 | int hwpoison_filter(struct page *p) | |
170 | { | |
171 | return 0; | |
172 | } | |
173 | #endif | |
174 | ||
7c116f2b WF |
175 | EXPORT_SYMBOL_GPL(hwpoison_filter); |
176 | ||
6a46079c | 177 | /* |
7329bbeb TL |
178 | * Send all the processes who have the page mapped a signal. |
179 | * ``action optional'' if they are not immediately affected by the error | |
180 | * ``action required'' if error happened in current execution context | |
6a46079c | 181 | */ |
7329bbeb TL |
182 | static int kill_proc(struct task_struct *t, unsigned long addr, int trapno, |
183 | unsigned long pfn, struct page *page, int flags) | |
6a46079c AK |
184 | { |
185 | struct siginfo si; | |
186 | int ret; | |
187 | ||
495367c0 CY |
188 | pr_err("Memory failure: %#lx: Killing %s:%d due to hardware memory corruption\n", |
189 | pfn, t->comm, t->pid); | |
6a46079c AK |
190 | si.si_signo = SIGBUS; |
191 | si.si_errno = 0; | |
6a46079c AK |
192 | si.si_addr = (void *)addr; |
193 | #ifdef __ARCH_SI_TRAPNO | |
194 | si.si_trapno = trapno; | |
195 | #endif | |
f9121153 | 196 | si.si_addr_lsb = compound_order(compound_head(page)) + PAGE_SHIFT; |
7329bbeb | 197 | |
a70ffcac | 198 | if ((flags & MF_ACTION_REQUIRED) && t->mm == current->mm) { |
7329bbeb | 199 | si.si_code = BUS_MCEERR_AR; |
a70ffcac | 200 | ret = force_sig_info(SIGBUS, &si, current); |
7329bbeb TL |
201 | } else { |
202 | /* | |
203 | * Don't use force here, it's convenient if the signal | |
204 | * can be temporarily blocked. | |
205 | * This could cause a loop when the user sets SIGBUS | |
206 | * to SIG_IGN, but hopefully no one will do that? | |
207 | */ | |
208 | si.si_code = BUS_MCEERR_AO; | |
209 | ret = send_sig_info(SIGBUS, &si, t); /* synchronous? */ | |
210 | } | |
6a46079c | 211 | if (ret < 0) |
495367c0 | 212 | pr_info("Memory failure: Error sending signal to %s:%d: %d\n", |
1170532b | 213 | t->comm, t->pid, ret); |
6a46079c AK |
214 | return ret; |
215 | } | |
216 | ||
588f9ce6 AK |
217 | /* |
218 | * When a unknown page type is encountered drain as many buffers as possible | |
219 | * in the hope to turn the page into a LRU or free page, which we can handle. | |
220 | */ | |
facb6011 | 221 | void shake_page(struct page *p, int access) |
588f9ce6 AK |
222 | { |
223 | if (!PageSlab(p)) { | |
224 | lru_add_drain_all(); | |
225 | if (PageLRU(p)) | |
226 | return; | |
c0554329 | 227 | drain_all_pages(page_zone(p)); |
588f9ce6 AK |
228 | if (PageLRU(p) || is_free_buddy_page(p)) |
229 | return; | |
230 | } | |
facb6011 | 231 | |
588f9ce6 | 232 | /* |
6b4f7799 JW |
233 | * Only call shrink_node_slabs here (which would also shrink |
234 | * other caches) if access is not potentially fatal. | |
588f9ce6 | 235 | */ |
cb731d6c VD |
236 | if (access) |
237 | drop_slab_node(page_to_nid(p)); | |
588f9ce6 AK |
238 | } |
239 | EXPORT_SYMBOL_GPL(shake_page); | |
240 | ||
6a46079c AK |
241 | /* |
242 | * Kill all processes that have a poisoned page mapped and then isolate | |
243 | * the page. | |
244 | * | |
245 | * General strategy: | |
246 | * Find all processes having the page mapped and kill them. | |
247 | * But we keep a page reference around so that the page is not | |
248 | * actually freed yet. | |
249 | * Then stash the page away | |
250 | * | |
251 | * There's no convenient way to get back to mapped processes | |
252 | * from the VMAs. So do a brute-force search over all | |
253 | * running processes. | |
254 | * | |
255 | * Remember that machine checks are not common (or rather | |
256 | * if they are common you have other problems), so this shouldn't | |
257 | * be a performance issue. | |
258 | * | |
259 | * Also there are some races possible while we get from the | |
260 | * error detection to actually handle it. | |
261 | */ | |
262 | ||
263 | struct to_kill { | |
264 | struct list_head nd; | |
265 | struct task_struct *tsk; | |
266 | unsigned long addr; | |
9033ae16 | 267 | char addr_valid; |
6a46079c AK |
268 | }; |
269 | ||
270 | /* | |
271 | * Failure handling: if we can't find or can't kill a process there's | |
272 | * not much we can do. We just print a message and ignore otherwise. | |
273 | */ | |
274 | ||
275 | /* | |
276 | * Schedule a process for later kill. | |
277 | * Uses GFP_ATOMIC allocations to avoid potential recursions in the VM. | |
278 | * TBD would GFP_NOIO be enough? | |
279 | */ | |
280 | static void add_to_kill(struct task_struct *tsk, struct page *p, | |
281 | struct vm_area_struct *vma, | |
282 | struct list_head *to_kill, | |
283 | struct to_kill **tkc) | |
284 | { | |
285 | struct to_kill *tk; | |
286 | ||
287 | if (*tkc) { | |
288 | tk = *tkc; | |
289 | *tkc = NULL; | |
290 | } else { | |
291 | tk = kmalloc(sizeof(struct to_kill), GFP_ATOMIC); | |
292 | if (!tk) { | |
495367c0 | 293 | pr_err("Memory failure: Out of memory while machine check handling\n"); |
6a46079c AK |
294 | return; |
295 | } | |
296 | } | |
297 | tk->addr = page_address_in_vma(p, vma); | |
298 | tk->addr_valid = 1; | |
299 | ||
300 | /* | |
301 | * In theory we don't have to kill when the page was | |
302 | * munmaped. But it could be also a mremap. Since that's | |
303 | * likely very rare kill anyways just out of paranoia, but use | |
304 | * a SIGKILL because the error is not contained anymore. | |
305 | */ | |
306 | if (tk->addr == -EFAULT) { | |
495367c0 | 307 | pr_info("Memory failure: Unable to find user space address %lx in %s\n", |
6a46079c AK |
308 | page_to_pfn(p), tsk->comm); |
309 | tk->addr_valid = 0; | |
310 | } | |
311 | get_task_struct(tsk); | |
312 | tk->tsk = tsk; | |
313 | list_add_tail(&tk->nd, to_kill); | |
314 | } | |
315 | ||
316 | /* | |
317 | * Kill the processes that have been collected earlier. | |
318 | * | |
319 | * Only do anything when DOIT is set, otherwise just free the list | |
320 | * (this is used for clean pages which do not need killing) | |
321 | * Also when FAIL is set do a force kill because something went | |
322 | * wrong earlier. | |
323 | */ | |
6751ed65 | 324 | static void kill_procs(struct list_head *to_kill, int forcekill, int trapno, |
7329bbeb TL |
325 | int fail, struct page *page, unsigned long pfn, |
326 | int flags) | |
6a46079c AK |
327 | { |
328 | struct to_kill *tk, *next; | |
329 | ||
330 | list_for_each_entry_safe (tk, next, to_kill, nd) { | |
6751ed65 | 331 | if (forcekill) { |
6a46079c | 332 | /* |
af901ca1 | 333 | * In case something went wrong with munmapping |
6a46079c AK |
334 | * make sure the process doesn't catch the |
335 | * signal and then access the memory. Just kill it. | |
6a46079c AK |
336 | */ |
337 | if (fail || tk->addr_valid == 0) { | |
495367c0 | 338 | pr_err("Memory failure: %#lx: forcibly killing %s:%d because of failure to unmap corrupted page\n", |
1170532b | 339 | pfn, tk->tsk->comm, tk->tsk->pid); |
6a46079c AK |
340 | force_sig(SIGKILL, tk->tsk); |
341 | } | |
342 | ||
343 | /* | |
344 | * In theory the process could have mapped | |
345 | * something else on the address in-between. We could | |
346 | * check for that, but we need to tell the | |
347 | * process anyways. | |
348 | */ | |
7329bbeb TL |
349 | else if (kill_proc(tk->tsk, tk->addr, trapno, |
350 | pfn, page, flags) < 0) | |
495367c0 | 351 | pr_err("Memory failure: %#lx: Cannot send advisory machine check signal to %s:%d\n", |
1170532b | 352 | pfn, tk->tsk->comm, tk->tsk->pid); |
6a46079c AK |
353 | } |
354 | put_task_struct(tk->tsk); | |
355 | kfree(tk); | |
356 | } | |
357 | } | |
358 | ||
3ba08129 NH |
359 | /* |
360 | * Find a dedicated thread which is supposed to handle SIGBUS(BUS_MCEERR_AO) | |
361 | * on behalf of the thread group. Return task_struct of the (first found) | |
362 | * dedicated thread if found, and return NULL otherwise. | |
363 | * | |
364 | * We already hold read_lock(&tasklist_lock) in the caller, so we don't | |
365 | * have to call rcu_read_lock/unlock() in this function. | |
366 | */ | |
367 | static struct task_struct *find_early_kill_thread(struct task_struct *tsk) | |
6a46079c | 368 | { |
3ba08129 NH |
369 | struct task_struct *t; |
370 | ||
371 | for_each_thread(tsk, t) | |
372 | if ((t->flags & PF_MCE_PROCESS) && (t->flags & PF_MCE_EARLY)) | |
373 | return t; | |
374 | return NULL; | |
375 | } | |
376 | ||
377 | /* | |
378 | * Determine whether a given process is "early kill" process which expects | |
379 | * to be signaled when some page under the process is hwpoisoned. | |
380 | * Return task_struct of the dedicated thread (main thread unless explicitly | |
381 | * specified) if the process is "early kill," and otherwise returns NULL. | |
382 | */ | |
383 | static struct task_struct *task_early_kill(struct task_struct *tsk, | |
384 | int force_early) | |
385 | { | |
386 | struct task_struct *t; | |
6a46079c | 387 | if (!tsk->mm) |
3ba08129 | 388 | return NULL; |
74614de1 | 389 | if (force_early) |
3ba08129 NH |
390 | return tsk; |
391 | t = find_early_kill_thread(tsk); | |
392 | if (t) | |
393 | return t; | |
394 | if (sysctl_memory_failure_early_kill) | |
395 | return tsk; | |
396 | return NULL; | |
6a46079c AK |
397 | } |
398 | ||
399 | /* | |
400 | * Collect processes when the error hit an anonymous page. | |
401 | */ | |
402 | static void collect_procs_anon(struct page *page, struct list_head *to_kill, | |
74614de1 | 403 | struct to_kill **tkc, int force_early) |
6a46079c AK |
404 | { |
405 | struct vm_area_struct *vma; | |
406 | struct task_struct *tsk; | |
407 | struct anon_vma *av; | |
bf181b9f | 408 | pgoff_t pgoff; |
6a46079c | 409 | |
4fc3f1d6 | 410 | av = page_lock_anon_vma_read(page); |
6a46079c | 411 | if (av == NULL) /* Not actually mapped anymore */ |
9b679320 PZ |
412 | return; |
413 | ||
a0f7a756 | 414 | pgoff = page_to_pgoff(page); |
9b679320 | 415 | read_lock(&tasklist_lock); |
6a46079c | 416 | for_each_process (tsk) { |
5beb4930 | 417 | struct anon_vma_chain *vmac; |
3ba08129 | 418 | struct task_struct *t = task_early_kill(tsk, force_early); |
5beb4930 | 419 | |
3ba08129 | 420 | if (!t) |
6a46079c | 421 | continue; |
bf181b9f ML |
422 | anon_vma_interval_tree_foreach(vmac, &av->rb_root, |
423 | pgoff, pgoff) { | |
5beb4930 | 424 | vma = vmac->vma; |
6a46079c AK |
425 | if (!page_mapped_in_vma(page, vma)) |
426 | continue; | |
3ba08129 NH |
427 | if (vma->vm_mm == t->mm) |
428 | add_to_kill(t, page, vma, to_kill, tkc); | |
6a46079c AK |
429 | } |
430 | } | |
6a46079c | 431 | read_unlock(&tasklist_lock); |
4fc3f1d6 | 432 | page_unlock_anon_vma_read(av); |
6a46079c AK |
433 | } |
434 | ||
435 | /* | |
436 | * Collect processes when the error hit a file mapped page. | |
437 | */ | |
438 | static void collect_procs_file(struct page *page, struct list_head *to_kill, | |
74614de1 | 439 | struct to_kill **tkc, int force_early) |
6a46079c AK |
440 | { |
441 | struct vm_area_struct *vma; | |
442 | struct task_struct *tsk; | |
6a46079c AK |
443 | struct address_space *mapping = page->mapping; |
444 | ||
d28eb9c8 | 445 | i_mmap_lock_read(mapping); |
9b679320 | 446 | read_lock(&tasklist_lock); |
6a46079c | 447 | for_each_process(tsk) { |
a0f7a756 | 448 | pgoff_t pgoff = page_to_pgoff(page); |
3ba08129 | 449 | struct task_struct *t = task_early_kill(tsk, force_early); |
6a46079c | 450 | |
3ba08129 | 451 | if (!t) |
6a46079c | 452 | continue; |
6b2dbba8 | 453 | vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, |
6a46079c AK |
454 | pgoff) { |
455 | /* | |
456 | * Send early kill signal to tasks where a vma covers | |
457 | * the page but the corrupted page is not necessarily | |
458 | * mapped it in its pte. | |
459 | * Assume applications who requested early kill want | |
460 | * to be informed of all such data corruptions. | |
461 | */ | |
3ba08129 NH |
462 | if (vma->vm_mm == t->mm) |
463 | add_to_kill(t, page, vma, to_kill, tkc); | |
6a46079c AK |
464 | } |
465 | } | |
6a46079c | 466 | read_unlock(&tasklist_lock); |
d28eb9c8 | 467 | i_mmap_unlock_read(mapping); |
6a46079c AK |
468 | } |
469 | ||
470 | /* | |
471 | * Collect the processes who have the corrupted page mapped to kill. | |
472 | * This is done in two steps for locking reasons. | |
473 | * First preallocate one tokill structure outside the spin locks, | |
474 | * so that we can kill at least one process reasonably reliable. | |
475 | */ | |
74614de1 TL |
476 | static void collect_procs(struct page *page, struct list_head *tokill, |
477 | int force_early) | |
6a46079c AK |
478 | { |
479 | struct to_kill *tk; | |
480 | ||
481 | if (!page->mapping) | |
482 | return; | |
483 | ||
484 | tk = kmalloc(sizeof(struct to_kill), GFP_NOIO); | |
485 | if (!tk) | |
486 | return; | |
487 | if (PageAnon(page)) | |
74614de1 | 488 | collect_procs_anon(page, tokill, &tk, force_early); |
6a46079c | 489 | else |
74614de1 | 490 | collect_procs_file(page, tokill, &tk, force_early); |
6a46079c AK |
491 | kfree(tk); |
492 | } | |
493 | ||
6a46079c | 494 | static const char *action_name[] = { |
cc637b17 XX |
495 | [MF_IGNORED] = "Ignored", |
496 | [MF_FAILED] = "Failed", | |
497 | [MF_DELAYED] = "Delayed", | |
498 | [MF_RECOVERED] = "Recovered", | |
64d37a2b NH |
499 | }; |
500 | ||
501 | static const char * const action_page_types[] = { | |
cc637b17 XX |
502 | [MF_MSG_KERNEL] = "reserved kernel page", |
503 | [MF_MSG_KERNEL_HIGH_ORDER] = "high-order kernel page", | |
504 | [MF_MSG_SLAB] = "kernel slab page", | |
505 | [MF_MSG_DIFFERENT_COMPOUND] = "different compound page after locking", | |
506 | [MF_MSG_POISONED_HUGE] = "huge page already hardware poisoned", | |
507 | [MF_MSG_HUGE] = "huge page", | |
508 | [MF_MSG_FREE_HUGE] = "free huge page", | |
509 | [MF_MSG_UNMAP_FAILED] = "unmapping failed page", | |
510 | [MF_MSG_DIRTY_SWAPCACHE] = "dirty swapcache page", | |
511 | [MF_MSG_CLEAN_SWAPCACHE] = "clean swapcache page", | |
512 | [MF_MSG_DIRTY_MLOCKED_LRU] = "dirty mlocked LRU page", | |
513 | [MF_MSG_CLEAN_MLOCKED_LRU] = "clean mlocked LRU page", | |
514 | [MF_MSG_DIRTY_UNEVICTABLE_LRU] = "dirty unevictable LRU page", | |
515 | [MF_MSG_CLEAN_UNEVICTABLE_LRU] = "clean unevictable LRU page", | |
516 | [MF_MSG_DIRTY_LRU] = "dirty LRU page", | |
517 | [MF_MSG_CLEAN_LRU] = "clean LRU page", | |
518 | [MF_MSG_TRUNCATED_LRU] = "already truncated LRU page", | |
519 | [MF_MSG_BUDDY] = "free buddy page", | |
520 | [MF_MSG_BUDDY_2ND] = "free buddy page (2nd try)", | |
521 | [MF_MSG_UNKNOWN] = "unknown page", | |
64d37a2b NH |
522 | }; |
523 | ||
dc2a1cbf WF |
524 | /* |
525 | * XXX: It is possible that a page is isolated from LRU cache, | |
526 | * and then kept in swap cache or failed to remove from page cache. | |
527 | * The page count will stop it from being freed by unpoison. | |
528 | * Stress tests should be aware of this memory leak problem. | |
529 | */ | |
530 | static int delete_from_lru_cache(struct page *p) | |
531 | { | |
532 | if (!isolate_lru_page(p)) { | |
533 | /* | |
534 | * Clear sensible page flags, so that the buddy system won't | |
535 | * complain when the page is unpoison-and-freed. | |
536 | */ | |
537 | ClearPageActive(p); | |
538 | ClearPageUnevictable(p); | |
539 | /* | |
540 | * drop the page count elevated by isolate_lru_page() | |
541 | */ | |
09cbfeaf | 542 | put_page(p); |
dc2a1cbf WF |
543 | return 0; |
544 | } | |
545 | return -EIO; | |
546 | } | |
547 | ||
6a46079c AK |
548 | /* |
549 | * Error hit kernel page. | |
550 | * Do nothing, try to be lucky and not touch this instead. For a few cases we | |
551 | * could be more sophisticated. | |
552 | */ | |
553 | static int me_kernel(struct page *p, unsigned long pfn) | |
6a46079c | 554 | { |
cc637b17 | 555 | return MF_IGNORED; |
6a46079c AK |
556 | } |
557 | ||
558 | /* | |
559 | * Page in unknown state. Do nothing. | |
560 | */ | |
561 | static int me_unknown(struct page *p, unsigned long pfn) | |
562 | { | |
495367c0 | 563 | pr_err("Memory failure: %#lx: Unknown page state\n", pfn); |
cc637b17 | 564 | return MF_FAILED; |
6a46079c AK |
565 | } |
566 | ||
6a46079c AK |
567 | /* |
568 | * Clean (or cleaned) page cache page. | |
569 | */ | |
570 | static int me_pagecache_clean(struct page *p, unsigned long pfn) | |
571 | { | |
572 | int err; | |
cc637b17 | 573 | int ret = MF_FAILED; |
6a46079c AK |
574 | struct address_space *mapping; |
575 | ||
dc2a1cbf WF |
576 | delete_from_lru_cache(p); |
577 | ||
6a46079c AK |
578 | /* |
579 | * For anonymous pages we're done the only reference left | |
580 | * should be the one m_f() holds. | |
581 | */ | |
582 | if (PageAnon(p)) | |
cc637b17 | 583 | return MF_RECOVERED; |
6a46079c AK |
584 | |
585 | /* | |
586 | * Now truncate the page in the page cache. This is really | |
587 | * more like a "temporary hole punch" | |
588 | * Don't do this for block devices when someone else | |
589 | * has a reference, because it could be file system metadata | |
590 | * and that's not safe to truncate. | |
591 | */ | |
592 | mapping = page_mapping(p); | |
593 | if (!mapping) { | |
594 | /* | |
595 | * Page has been teared down in the meanwhile | |
596 | */ | |
cc637b17 | 597 | return MF_FAILED; |
6a46079c AK |
598 | } |
599 | ||
600 | /* | |
601 | * Truncation is a bit tricky. Enable it per file system for now. | |
602 | * | |
603 | * Open: to take i_mutex or not for this? Right now we don't. | |
604 | */ | |
605 | if (mapping->a_ops->error_remove_page) { | |
606 | err = mapping->a_ops->error_remove_page(mapping, p); | |
607 | if (err != 0) { | |
495367c0 | 608 | pr_info("Memory failure: %#lx: Failed to punch page: %d\n", |
1170532b | 609 | pfn, err); |
6a46079c AK |
610 | } else if (page_has_private(p) && |
611 | !try_to_release_page(p, GFP_NOIO)) { | |
495367c0 CY |
612 | pr_info("Memory failure: %#lx: failed to release buffers\n", |
613 | pfn); | |
6a46079c | 614 | } else { |
cc637b17 | 615 | ret = MF_RECOVERED; |
6a46079c AK |
616 | } |
617 | } else { | |
618 | /* | |
619 | * If the file system doesn't support it just invalidate | |
620 | * This fails on dirty or anything with private pages | |
621 | */ | |
622 | if (invalidate_inode_page(p)) | |
cc637b17 | 623 | ret = MF_RECOVERED; |
6a46079c | 624 | else |
495367c0 CY |
625 | pr_info("Memory failure: %#lx: Failed to invalidate\n", |
626 | pfn); | |
6a46079c AK |
627 | } |
628 | return ret; | |
629 | } | |
630 | ||
631 | /* | |
549543df | 632 | * Dirty pagecache page |
6a46079c AK |
633 | * Issues: when the error hit a hole page the error is not properly |
634 | * propagated. | |
635 | */ | |
636 | static int me_pagecache_dirty(struct page *p, unsigned long pfn) | |
637 | { | |
638 | struct address_space *mapping = page_mapping(p); | |
639 | ||
640 | SetPageError(p); | |
641 | /* TBD: print more information about the file. */ | |
642 | if (mapping) { | |
643 | /* | |
644 | * IO error will be reported by write(), fsync(), etc. | |
645 | * who check the mapping. | |
646 | * This way the application knows that something went | |
647 | * wrong with its dirty file data. | |
648 | * | |
649 | * There's one open issue: | |
650 | * | |
651 | * The EIO will be only reported on the next IO | |
652 | * operation and then cleared through the IO map. | |
653 | * Normally Linux has two mechanisms to pass IO error | |
654 | * first through the AS_EIO flag in the address space | |
655 | * and then through the PageError flag in the page. | |
656 | * Since we drop pages on memory failure handling the | |
657 | * only mechanism open to use is through AS_AIO. | |
658 | * | |
659 | * This has the disadvantage that it gets cleared on | |
660 | * the first operation that returns an error, while | |
661 | * the PageError bit is more sticky and only cleared | |
662 | * when the page is reread or dropped. If an | |
663 | * application assumes it will always get error on | |
664 | * fsync, but does other operations on the fd before | |
25985edc | 665 | * and the page is dropped between then the error |
6a46079c AK |
666 | * will not be properly reported. |
667 | * | |
668 | * This can already happen even without hwpoisoned | |
669 | * pages: first on metadata IO errors (which only | |
670 | * report through AS_EIO) or when the page is dropped | |
671 | * at the wrong time. | |
672 | * | |
673 | * So right now we assume that the application DTRT on | |
674 | * the first EIO, but we're not worse than other parts | |
675 | * of the kernel. | |
676 | */ | |
677 | mapping_set_error(mapping, EIO); | |
678 | } | |
679 | ||
680 | return me_pagecache_clean(p, pfn); | |
681 | } | |
682 | ||
683 | /* | |
684 | * Clean and dirty swap cache. | |
685 | * | |
686 | * Dirty swap cache page is tricky to handle. The page could live both in page | |
687 | * cache and swap cache(ie. page is freshly swapped in). So it could be | |
688 | * referenced concurrently by 2 types of PTEs: | |
689 | * normal PTEs and swap PTEs. We try to handle them consistently by calling | |
690 | * try_to_unmap(TTU_IGNORE_HWPOISON) to convert the normal PTEs to swap PTEs, | |
691 | * and then | |
692 | * - clear dirty bit to prevent IO | |
693 | * - remove from LRU | |
694 | * - but keep in the swap cache, so that when we return to it on | |
695 | * a later page fault, we know the application is accessing | |
696 | * corrupted data and shall be killed (we installed simple | |
697 | * interception code in do_swap_page to catch it). | |
698 | * | |
699 | * Clean swap cache pages can be directly isolated. A later page fault will | |
700 | * bring in the known good data from disk. | |
701 | */ | |
702 | static int me_swapcache_dirty(struct page *p, unsigned long pfn) | |
703 | { | |
6a46079c AK |
704 | ClearPageDirty(p); |
705 | /* Trigger EIO in shmem: */ | |
706 | ClearPageUptodate(p); | |
707 | ||
dc2a1cbf | 708 | if (!delete_from_lru_cache(p)) |
cc637b17 | 709 | return MF_DELAYED; |
dc2a1cbf | 710 | else |
cc637b17 | 711 | return MF_FAILED; |
6a46079c AK |
712 | } |
713 | ||
714 | static int me_swapcache_clean(struct page *p, unsigned long pfn) | |
715 | { | |
6a46079c | 716 | delete_from_swap_cache(p); |
e43c3afb | 717 | |
dc2a1cbf | 718 | if (!delete_from_lru_cache(p)) |
cc637b17 | 719 | return MF_RECOVERED; |
dc2a1cbf | 720 | else |
cc637b17 | 721 | return MF_FAILED; |
6a46079c AK |
722 | } |
723 | ||
724 | /* | |
725 | * Huge pages. Needs work. | |
726 | * Issues: | |
93f70f90 NH |
727 | * - Error on hugepage is contained in hugepage unit (not in raw page unit.) |
728 | * To narrow down kill region to one page, we need to break up pmd. | |
6a46079c AK |
729 | */ |
730 | static int me_huge_page(struct page *p, unsigned long pfn) | |
731 | { | |
6de2b1aa | 732 | int res = 0; |
93f70f90 | 733 | struct page *hpage = compound_head(p); |
2491ffee NH |
734 | |
735 | if (!PageHuge(hpage)) | |
736 | return MF_DELAYED; | |
737 | ||
93f70f90 NH |
738 | /* |
739 | * We can safely recover from error on free or reserved (i.e. | |
740 | * not in-use) hugepage by dequeuing it from freelist. | |
741 | * To check whether a hugepage is in-use or not, we can't use | |
742 | * page->lru because it can be used in other hugepage operations, | |
743 | * such as __unmap_hugepage_range() and gather_surplus_pages(). | |
744 | * So instead we use page_mapping() and PageAnon(). | |
93f70f90 NH |
745 | */ |
746 | if (!(page_mapping(hpage) || PageAnon(hpage))) { | |
6de2b1aa NH |
747 | res = dequeue_hwpoisoned_huge_page(hpage); |
748 | if (!res) | |
cc637b17 | 749 | return MF_RECOVERED; |
93f70f90 | 750 | } |
cc637b17 | 751 | return MF_DELAYED; |
6a46079c AK |
752 | } |
753 | ||
754 | /* | |
755 | * Various page states we can handle. | |
756 | * | |
757 | * A page state is defined by its current page->flags bits. | |
758 | * The table matches them in order and calls the right handler. | |
759 | * | |
760 | * This is quite tricky because we can access page at any time | |
25985edc | 761 | * in its live cycle, so all accesses have to be extremely careful. |
6a46079c AK |
762 | * |
763 | * This is not complete. More states could be added. | |
764 | * For any missing state don't attempt recovery. | |
765 | */ | |
766 | ||
767 | #define dirty (1UL << PG_dirty) | |
6326fec1 | 768 | #define sc ((1UL << PG_swapcache) | (1UL << PG_swapbacked)) |
6a46079c AK |
769 | #define unevict (1UL << PG_unevictable) |
770 | #define mlock (1UL << PG_mlocked) | |
771 | #define writeback (1UL << PG_writeback) | |
772 | #define lru (1UL << PG_lru) | |
6a46079c | 773 | #define head (1UL << PG_head) |
6a46079c | 774 | #define slab (1UL << PG_slab) |
6a46079c AK |
775 | #define reserved (1UL << PG_reserved) |
776 | ||
777 | static struct page_state { | |
778 | unsigned long mask; | |
779 | unsigned long res; | |
cc637b17 | 780 | enum mf_action_page_type type; |
6a46079c AK |
781 | int (*action)(struct page *p, unsigned long pfn); |
782 | } error_states[] = { | |
cc637b17 | 783 | { reserved, reserved, MF_MSG_KERNEL, me_kernel }, |
95d01fc6 WF |
784 | /* |
785 | * free pages are specially detected outside this table: | |
786 | * PG_buddy pages only make a small fraction of all free pages. | |
787 | */ | |
6a46079c AK |
788 | |
789 | /* | |
790 | * Could in theory check if slab page is free or if we can drop | |
791 | * currently unused objects without touching them. But just | |
792 | * treat it as standard kernel for now. | |
793 | */ | |
cc637b17 | 794 | { slab, slab, MF_MSG_SLAB, me_kernel }, |
6a46079c | 795 | |
cc637b17 | 796 | { head, head, MF_MSG_HUGE, me_huge_page }, |
6a46079c | 797 | |
cc637b17 XX |
798 | { sc|dirty, sc|dirty, MF_MSG_DIRTY_SWAPCACHE, me_swapcache_dirty }, |
799 | { sc|dirty, sc, MF_MSG_CLEAN_SWAPCACHE, me_swapcache_clean }, | |
6a46079c | 800 | |
cc637b17 XX |
801 | { mlock|dirty, mlock|dirty, MF_MSG_DIRTY_MLOCKED_LRU, me_pagecache_dirty }, |
802 | { mlock|dirty, mlock, MF_MSG_CLEAN_MLOCKED_LRU, me_pagecache_clean }, | |
6a46079c | 803 | |
cc637b17 XX |
804 | { unevict|dirty, unevict|dirty, MF_MSG_DIRTY_UNEVICTABLE_LRU, me_pagecache_dirty }, |
805 | { unevict|dirty, unevict, MF_MSG_CLEAN_UNEVICTABLE_LRU, me_pagecache_clean }, | |
5f4b9fc5 | 806 | |
cc637b17 XX |
807 | { lru|dirty, lru|dirty, MF_MSG_DIRTY_LRU, me_pagecache_dirty }, |
808 | { lru|dirty, lru, MF_MSG_CLEAN_LRU, me_pagecache_clean }, | |
6a46079c AK |
809 | |
810 | /* | |
811 | * Catchall entry: must be at end. | |
812 | */ | |
cc637b17 | 813 | { 0, 0, MF_MSG_UNKNOWN, me_unknown }, |
6a46079c AK |
814 | }; |
815 | ||
2326c467 AK |
816 | #undef dirty |
817 | #undef sc | |
818 | #undef unevict | |
819 | #undef mlock | |
820 | #undef writeback | |
821 | #undef lru | |
2326c467 | 822 | #undef head |
2326c467 AK |
823 | #undef slab |
824 | #undef reserved | |
825 | ||
ff604cf6 NH |
826 | /* |
827 | * "Dirty/Clean" indication is not 100% accurate due to the possibility of | |
828 | * setting PG_dirty outside page lock. See also comment above set_page_dirty(). | |
829 | */ | |
cc3e2af4 XX |
830 | static void action_result(unsigned long pfn, enum mf_action_page_type type, |
831 | enum mf_result result) | |
6a46079c | 832 | { |
97f0b134 XX |
833 | trace_memory_failure_event(pfn, type, result); |
834 | ||
495367c0 | 835 | pr_err("Memory failure: %#lx: recovery action for %s: %s\n", |
64d37a2b | 836 | pfn, action_page_types[type], action_name[result]); |
6a46079c AK |
837 | } |
838 | ||
839 | static int page_action(struct page_state *ps, struct page *p, | |
bd1ce5f9 | 840 | unsigned long pfn) |
6a46079c AK |
841 | { |
842 | int result; | |
7456b040 | 843 | int count; |
6a46079c AK |
844 | |
845 | result = ps->action(p, pfn); | |
7456b040 | 846 | |
bd1ce5f9 | 847 | count = page_count(p) - 1; |
cc637b17 | 848 | if (ps->action == me_swapcache_dirty && result == MF_DELAYED) |
138ce286 WF |
849 | count--; |
850 | if (count != 0) { | |
495367c0 | 851 | pr_err("Memory failure: %#lx: %s still referenced by %d users\n", |
64d37a2b | 852 | pfn, action_page_types[ps->type], count); |
cc637b17 | 853 | result = MF_FAILED; |
138ce286 | 854 | } |
64d37a2b | 855 | action_result(pfn, ps->type, result); |
6a46079c AK |
856 | |
857 | /* Could do more checks here if page looks ok */ | |
858 | /* | |
859 | * Could adjust zone counters here to correct for the missing page. | |
860 | */ | |
861 | ||
cc637b17 | 862 | return (result == MF_RECOVERED || result == MF_DELAYED) ? 0 : -EBUSY; |
6a46079c AK |
863 | } |
864 | ||
ead07f6a NH |
865 | /** |
866 | * get_hwpoison_page() - Get refcount for memory error handling: | |
867 | * @page: raw error page (hit by memory error) | |
868 | * | |
869 | * Return: return 0 if failed to grab the refcount, otherwise true (some | |
870 | * non-zero value.) | |
871 | */ | |
872 | int get_hwpoison_page(struct page *page) | |
873 | { | |
874 | struct page *head = compound_head(page); | |
875 | ||
4e41a30c | 876 | if (!PageHuge(head) && PageTransHuge(head)) { |
98ed2b00 NH |
877 | /* |
878 | * Non anonymous thp exists only in allocation/free time. We | |
879 | * can't handle such a case correctly, so let's give it up. | |
880 | * This should be better than triggering BUG_ON when kernel | |
881 | * tries to touch the "partially handled" page. | |
882 | */ | |
883 | if (!PageAnon(head)) { | |
495367c0 | 884 | pr_err("Memory failure: %#lx: non anonymous thp\n", |
98ed2b00 NH |
885 | page_to_pfn(page)); |
886 | return 0; | |
887 | } | |
ead07f6a NH |
888 | } |
889 | ||
c2e7e00b KK |
890 | if (get_page_unless_zero(head)) { |
891 | if (head == compound_head(page)) | |
892 | return 1; | |
893 | ||
495367c0 CY |
894 | pr_info("Memory failure: %#lx cannot catch tail\n", |
895 | page_to_pfn(page)); | |
c2e7e00b KK |
896 | put_page(head); |
897 | } | |
898 | ||
899 | return 0; | |
ead07f6a NH |
900 | } |
901 | EXPORT_SYMBOL_GPL(get_hwpoison_page); | |
902 | ||
6a46079c AK |
903 | /* |
904 | * Do all that is necessary to remove user space mappings. Unmap | |
905 | * the pages and send SIGBUS to the processes if the data was dirty. | |
906 | */ | |
1668bfd5 | 907 | static int hwpoison_user_mappings(struct page *p, unsigned long pfn, |
54b9dd14 | 908 | int trapno, int flags, struct page **hpagep) |
6a46079c AK |
909 | { |
910 | enum ttu_flags ttu = TTU_UNMAP | TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS; | |
911 | struct address_space *mapping; | |
912 | LIST_HEAD(tokill); | |
913 | int ret; | |
6751ed65 | 914 | int kill = 1, forcekill; |
54b9dd14 | 915 | struct page *hpage = *hpagep; |
6a46079c | 916 | |
93a9eb39 NH |
917 | /* |
918 | * Here we are interested only in user-mapped pages, so skip any | |
919 | * other types of pages. | |
920 | */ | |
921 | if (PageReserved(p) || PageSlab(p)) | |
922 | return SWAP_SUCCESS; | |
923 | if (!(PageLRU(hpage) || PageHuge(p))) | |
1668bfd5 | 924 | return SWAP_SUCCESS; |
6a46079c | 925 | |
6a46079c AK |
926 | /* |
927 | * This check implies we don't kill processes if their pages | |
928 | * are in the swap cache early. Those are always late kills. | |
929 | */ | |
7af446a8 | 930 | if (!page_mapped(hpage)) |
1668bfd5 WF |
931 | return SWAP_SUCCESS; |
932 | ||
52089b14 | 933 | if (PageKsm(p)) { |
495367c0 | 934 | pr_err("Memory failure: %#lx: can't handle KSM pages.\n", pfn); |
1668bfd5 | 935 | return SWAP_FAIL; |
52089b14 | 936 | } |
6a46079c AK |
937 | |
938 | if (PageSwapCache(p)) { | |
495367c0 CY |
939 | pr_err("Memory failure: %#lx: keeping poisoned page in swap cache\n", |
940 | pfn); | |
6a46079c AK |
941 | ttu |= TTU_IGNORE_HWPOISON; |
942 | } | |
943 | ||
944 | /* | |
945 | * Propagate the dirty bit from PTEs to struct page first, because we | |
946 | * need this to decide if we should kill or just drop the page. | |
db0480b3 WF |
947 | * XXX: the dirty test could be racy: set_page_dirty() may not always |
948 | * be called inside page lock (it's recommended but not enforced). | |
6a46079c | 949 | */ |
7af446a8 | 950 | mapping = page_mapping(hpage); |
6751ed65 | 951 | if (!(flags & MF_MUST_KILL) && !PageDirty(hpage) && mapping && |
7af446a8 NH |
952 | mapping_cap_writeback_dirty(mapping)) { |
953 | if (page_mkclean(hpage)) { | |
954 | SetPageDirty(hpage); | |
6a46079c AK |
955 | } else { |
956 | kill = 0; | |
957 | ttu |= TTU_IGNORE_HWPOISON; | |
495367c0 | 958 | pr_info("Memory failure: %#lx: corrupted page was clean: dropped without side effects\n", |
6a46079c AK |
959 | pfn); |
960 | } | |
961 | } | |
962 | ||
963 | /* | |
964 | * First collect all the processes that have the page | |
965 | * mapped in dirty form. This has to be done before try_to_unmap, | |
966 | * because ttu takes the rmap data structures down. | |
967 | * | |
968 | * Error handling: We ignore errors here because | |
969 | * there's nothing that can be done. | |
970 | */ | |
971 | if (kill) | |
415c64c1 | 972 | collect_procs(hpage, &tokill, flags & MF_ACTION_REQUIRED); |
6a46079c | 973 | |
415c64c1 | 974 | ret = try_to_unmap(hpage, ttu); |
6a46079c | 975 | if (ret != SWAP_SUCCESS) |
495367c0 | 976 | pr_err("Memory failure: %#lx: failed to unmap page (mapcount=%d)\n", |
1170532b | 977 | pfn, page_mapcount(hpage)); |
a6d30ddd | 978 | |
6a46079c AK |
979 | /* |
980 | * Now that the dirty bit has been propagated to the | |
981 | * struct page and all unmaps done we can decide if | |
982 | * killing is needed or not. Only kill when the page | |
6751ed65 TL |
983 | * was dirty or the process is not restartable, |
984 | * otherwise the tokill list is merely | |
6a46079c AK |
985 | * freed. When there was a problem unmapping earlier |
986 | * use a more force-full uncatchable kill to prevent | |
987 | * any accesses to the poisoned memory. | |
988 | */ | |
415c64c1 | 989 | forcekill = PageDirty(hpage) || (flags & MF_MUST_KILL); |
6751ed65 | 990 | kill_procs(&tokill, forcekill, trapno, |
7329bbeb | 991 | ret != SWAP_SUCCESS, p, pfn, flags); |
1668bfd5 WF |
992 | |
993 | return ret; | |
6a46079c AK |
994 | } |
995 | ||
7013febc NH |
996 | static void set_page_hwpoison_huge_page(struct page *hpage) |
997 | { | |
998 | int i; | |
f9121153 | 999 | int nr_pages = 1 << compound_order(hpage); |
7013febc NH |
1000 | for (i = 0; i < nr_pages; i++) |
1001 | SetPageHWPoison(hpage + i); | |
1002 | } | |
1003 | ||
1004 | static void clear_page_hwpoison_huge_page(struct page *hpage) | |
1005 | { | |
1006 | int i; | |
f9121153 | 1007 | int nr_pages = 1 << compound_order(hpage); |
7013febc NH |
1008 | for (i = 0; i < nr_pages; i++) |
1009 | ClearPageHWPoison(hpage + i); | |
1010 | } | |
1011 | ||
cd42f4a3 TL |
1012 | /** |
1013 | * memory_failure - Handle memory failure of a page. | |
1014 | * @pfn: Page Number of the corrupted page | |
1015 | * @trapno: Trap number reported in the signal to user space. | |
1016 | * @flags: fine tune action taken | |
1017 | * | |
1018 | * This function is called by the low level machine check code | |
1019 | * of an architecture when it detects hardware memory corruption | |
1020 | * of a page. It tries its best to recover, which includes | |
1021 | * dropping pages, killing processes etc. | |
1022 | * | |
1023 | * The function is primarily of use for corruptions that | |
1024 | * happen outside the current execution context (e.g. when | |
1025 | * detected by a background scrubber) | |
1026 | * | |
1027 | * Must run in process context (e.g. a work queue) with interrupts | |
1028 | * enabled and no spinlocks hold. | |
1029 | */ | |
1030 | int memory_failure(unsigned long pfn, int trapno, int flags) | |
6a46079c AK |
1031 | { |
1032 | struct page_state *ps; | |
1033 | struct page *p; | |
7af446a8 | 1034 | struct page *hpage; |
415c64c1 | 1035 | struct page *orig_head; |
6a46079c | 1036 | int res; |
c9fbdd5f | 1037 | unsigned int nr_pages; |
524fca1e | 1038 | unsigned long page_flags; |
6a46079c AK |
1039 | |
1040 | if (!sysctl_memory_failure_recovery) | |
1041 | panic("Memory failure from trap %d on page %lx", trapno, pfn); | |
1042 | ||
1043 | if (!pfn_valid(pfn)) { | |
495367c0 CY |
1044 | pr_err("Memory failure: %#lx: memory outside kernel control\n", |
1045 | pfn); | |
a7560fc8 | 1046 | return -ENXIO; |
6a46079c AK |
1047 | } |
1048 | ||
1049 | p = pfn_to_page(pfn); | |
415c64c1 | 1050 | orig_head = hpage = compound_head(p); |
6a46079c | 1051 | if (TestSetPageHWPoison(p)) { |
495367c0 CY |
1052 | pr_err("Memory failure: %#lx: already hardware poisoned\n", |
1053 | pfn); | |
6a46079c AK |
1054 | return 0; |
1055 | } | |
1056 | ||
4db0e950 NH |
1057 | /* |
1058 | * Currently errors on hugetlbfs pages are measured in hugepage units, | |
1059 | * so nr_pages should be 1 << compound_order. OTOH when errors are on | |
1060 | * transparent hugepages, they are supposed to be split and error | |
1061 | * measurement is done in normal page units. So nr_pages should be one | |
1062 | * in this case. | |
1063 | */ | |
1064 | if (PageHuge(p)) | |
1065 | nr_pages = 1 << compound_order(hpage); | |
1066 | else /* normal page or thp */ | |
1067 | nr_pages = 1; | |
8e30456b | 1068 | num_poisoned_pages_add(nr_pages); |
6a46079c AK |
1069 | |
1070 | /* | |
1071 | * We need/can do nothing about count=0 pages. | |
1072 | * 1) it's a free page, and therefore in safe hand: | |
1073 | * prep_new_page() will be the gate keeper. | |
8c6c2ecb NH |
1074 | * 2) it's a free hugepage, which is also safe: |
1075 | * an affected hugepage will be dequeued from hugepage freelist, | |
1076 | * so there's no concern about reusing it ever after. | |
1077 | * 3) it's part of a non-compound high order page. | |
6a46079c AK |
1078 | * Implies some kernel user: cannot stop them from |
1079 | * R/W the page; let's pray that the page has been | |
1080 | * used and will be freed some time later. | |
1081 | * In fact it's dangerous to directly bump up page count from 0, | |
1082 | * that may make page_freeze_refs()/page_unfreeze_refs() mismatch. | |
1083 | */ | |
ead07f6a | 1084 | if (!(flags & MF_COUNT_INCREASED) && !get_hwpoison_page(p)) { |
8d22ba1b | 1085 | if (is_free_buddy_page(p)) { |
cc637b17 | 1086 | action_result(pfn, MF_MSG_BUDDY, MF_DELAYED); |
8d22ba1b | 1087 | return 0; |
8c6c2ecb NH |
1088 | } else if (PageHuge(hpage)) { |
1089 | /* | |
b985194c | 1090 | * Check "filter hit" and "race with other subpage." |
8c6c2ecb | 1091 | */ |
7eaceacc | 1092 | lock_page(hpage); |
b985194c CY |
1093 | if (PageHWPoison(hpage)) { |
1094 | if ((hwpoison_filter(p) && TestClearPageHWPoison(p)) | |
1095 | || (p != hpage && TestSetPageHWPoison(hpage))) { | |
8e30456b | 1096 | num_poisoned_pages_sub(nr_pages); |
b985194c CY |
1097 | unlock_page(hpage); |
1098 | return 0; | |
1099 | } | |
8c6c2ecb NH |
1100 | } |
1101 | set_page_hwpoison_huge_page(hpage); | |
1102 | res = dequeue_hwpoisoned_huge_page(hpage); | |
cc637b17 XX |
1103 | action_result(pfn, MF_MSG_FREE_HUGE, |
1104 | res ? MF_IGNORED : MF_DELAYED); | |
8c6c2ecb NH |
1105 | unlock_page(hpage); |
1106 | return res; | |
8d22ba1b | 1107 | } else { |
cc637b17 | 1108 | action_result(pfn, MF_MSG_KERNEL_HIGH_ORDER, MF_IGNORED); |
8d22ba1b WF |
1109 | return -EBUSY; |
1110 | } | |
6a46079c AK |
1111 | } |
1112 | ||
415c64c1 | 1113 | if (!PageHuge(p) && PageTransHuge(hpage)) { |
c3901e72 NH |
1114 | lock_page(p); |
1115 | if (!PageAnon(p) || unlikely(split_huge_page(p))) { | |
1116 | unlock_page(p); | |
1117 | if (!PageAnon(p)) | |
495367c0 CY |
1118 | pr_err("Memory failure: %#lx: non anonymous thp\n", |
1119 | pfn); | |
7f6bf39b | 1120 | else |
495367c0 CY |
1121 | pr_err("Memory failure: %#lx: thp split failed\n", |
1122 | pfn); | |
ead07f6a | 1123 | if (TestClearPageHWPoison(p)) |
8e30456b | 1124 | num_poisoned_pages_sub(nr_pages); |
665d9da7 | 1125 | put_hwpoison_page(p); |
415c64c1 NH |
1126 | return -EBUSY; |
1127 | } | |
c3901e72 | 1128 | unlock_page(p); |
415c64c1 NH |
1129 | VM_BUG_ON_PAGE(!page_count(p), p); |
1130 | hpage = compound_head(p); | |
1131 | } | |
1132 | ||
e43c3afb WF |
1133 | /* |
1134 | * We ignore non-LRU pages for good reasons. | |
1135 | * - PG_locked is only well defined for LRU pages and a few others | |
48c935ad | 1136 | * - to avoid races with __SetPageLocked() |
e43c3afb WF |
1137 | * - to avoid races with __SetPageSlab*() (and more non-atomic ops) |
1138 | * The check (unnecessarily) ignores LRU pages being isolated and | |
1139 | * walked by the page reclaim code, however that's not a big loss. | |
1140 | */ | |
09789e5d | 1141 | if (!PageHuge(p)) { |
415c64c1 NH |
1142 | if (!PageLRU(p)) |
1143 | shake_page(p, 0); | |
1144 | if (!PageLRU(p)) { | |
af241a08 JD |
1145 | /* |
1146 | * shake_page could have turned it free. | |
1147 | */ | |
1148 | if (is_free_buddy_page(p)) { | |
2d421acd | 1149 | if (flags & MF_COUNT_INCREASED) |
cc637b17 | 1150 | action_result(pfn, MF_MSG_BUDDY, MF_DELAYED); |
2d421acd | 1151 | else |
cc637b17 XX |
1152 | action_result(pfn, MF_MSG_BUDDY_2ND, |
1153 | MF_DELAYED); | |
af241a08 JD |
1154 | return 0; |
1155 | } | |
0474a60e | 1156 | } |
e43c3afb | 1157 | } |
e43c3afb | 1158 | |
7eaceacc | 1159 | lock_page(hpage); |
847ce401 | 1160 | |
f37d4298 AK |
1161 | /* |
1162 | * The page could have changed compound pages during the locking. | |
1163 | * If this happens just bail out. | |
1164 | */ | |
415c64c1 | 1165 | if (PageCompound(p) && compound_head(p) != orig_head) { |
cc637b17 | 1166 | action_result(pfn, MF_MSG_DIFFERENT_COMPOUND, MF_IGNORED); |
f37d4298 AK |
1167 | res = -EBUSY; |
1168 | goto out; | |
1169 | } | |
1170 | ||
524fca1e NH |
1171 | /* |
1172 | * We use page flags to determine what action should be taken, but | |
1173 | * the flags can be modified by the error containment action. One | |
1174 | * example is an mlocked page, where PG_mlocked is cleared by | |
1175 | * page_remove_rmap() in try_to_unmap_one(). So to determine page status | |
1176 | * correctly, we save a copy of the page flags at this time. | |
1177 | */ | |
1178 | page_flags = p->flags; | |
1179 | ||
847ce401 WF |
1180 | /* |
1181 | * unpoison always clear PG_hwpoison inside page lock | |
1182 | */ | |
1183 | if (!PageHWPoison(p)) { | |
495367c0 | 1184 | pr_err("Memory failure: %#lx: just unpoisoned\n", pfn); |
8e30456b | 1185 | num_poisoned_pages_sub(nr_pages); |
a09233f3 | 1186 | unlock_page(hpage); |
665d9da7 | 1187 | put_hwpoison_page(hpage); |
a09233f3 | 1188 | return 0; |
847ce401 | 1189 | } |
7c116f2b WF |
1190 | if (hwpoison_filter(p)) { |
1191 | if (TestClearPageHWPoison(p)) | |
8e30456b | 1192 | num_poisoned_pages_sub(nr_pages); |
7af446a8 | 1193 | unlock_page(hpage); |
665d9da7 | 1194 | put_hwpoison_page(hpage); |
7c116f2b WF |
1195 | return 0; |
1196 | } | |
847ce401 | 1197 | |
0bc1f8b0 CY |
1198 | if (!PageHuge(p) && !PageTransTail(p) && !PageLRU(p)) |
1199 | goto identify_page_state; | |
1200 | ||
7013febc NH |
1201 | /* |
1202 | * For error on the tail page, we should set PG_hwpoison | |
1203 | * on the head page to show that the hugepage is hwpoisoned | |
1204 | */ | |
a6d30ddd | 1205 | if (PageHuge(p) && PageTail(p) && TestSetPageHWPoison(hpage)) { |
cc637b17 | 1206 | action_result(pfn, MF_MSG_POISONED_HUGE, MF_IGNORED); |
7013febc | 1207 | unlock_page(hpage); |
665d9da7 | 1208 | put_hwpoison_page(hpage); |
7013febc NH |
1209 | return 0; |
1210 | } | |
1211 | /* | |
1212 | * Set PG_hwpoison on all pages in an error hugepage, | |
1213 | * because containment is done in hugepage unit for now. | |
1214 | * Since we have done TestSetPageHWPoison() for the head page with | |
1215 | * page lock held, we can safely set PG_hwpoison bits on tail pages. | |
1216 | */ | |
1217 | if (PageHuge(p)) | |
1218 | set_page_hwpoison_huge_page(hpage); | |
1219 | ||
6edd6cc6 NH |
1220 | /* |
1221 | * It's very difficult to mess with pages currently under IO | |
1222 | * and in many cases impossible, so we just avoid it here. | |
1223 | */ | |
6a46079c AK |
1224 | wait_on_page_writeback(p); |
1225 | ||
1226 | /* | |
1227 | * Now take care of user space mappings. | |
e64a782f | 1228 | * Abort on fail: __delete_from_page_cache() assumes unmapped page. |
54b9dd14 NH |
1229 | * |
1230 | * When the raw error page is thp tail page, hpage points to the raw | |
1231 | * page after thp split. | |
6a46079c | 1232 | */ |
54b9dd14 NH |
1233 | if (hwpoison_user_mappings(p, pfn, trapno, flags, &hpage) |
1234 | != SWAP_SUCCESS) { | |
cc637b17 | 1235 | action_result(pfn, MF_MSG_UNMAP_FAILED, MF_IGNORED); |
1668bfd5 WF |
1236 | res = -EBUSY; |
1237 | goto out; | |
1238 | } | |
6a46079c AK |
1239 | |
1240 | /* | |
1241 | * Torn down by someone else? | |
1242 | */ | |
dc2a1cbf | 1243 | if (PageLRU(p) && !PageSwapCache(p) && p->mapping == NULL) { |
cc637b17 | 1244 | action_result(pfn, MF_MSG_TRUNCATED_LRU, MF_IGNORED); |
d95ea51e | 1245 | res = -EBUSY; |
6a46079c AK |
1246 | goto out; |
1247 | } | |
1248 | ||
0bc1f8b0 | 1249 | identify_page_state: |
6a46079c | 1250 | res = -EBUSY; |
524fca1e NH |
1251 | /* |
1252 | * The first check uses the current page flags which may not have any | |
1253 | * relevant information. The second check with the saved page flagss is | |
1254 | * carried out only if the first check can't determine the page status. | |
1255 | */ | |
1256 | for (ps = error_states;; ps++) | |
1257 | if ((p->flags & ps->mask) == ps->res) | |
6a46079c | 1258 | break; |
841fcc58 WL |
1259 | |
1260 | page_flags |= (p->flags & (1UL << PG_dirty)); | |
1261 | ||
524fca1e NH |
1262 | if (!ps->mask) |
1263 | for (ps = error_states;; ps++) | |
1264 | if ((page_flags & ps->mask) == ps->res) | |
1265 | break; | |
1266 | res = page_action(ps, p, pfn); | |
6a46079c | 1267 | out: |
7af446a8 | 1268 | unlock_page(hpage); |
6a46079c AK |
1269 | return res; |
1270 | } | |
cd42f4a3 | 1271 | EXPORT_SYMBOL_GPL(memory_failure); |
847ce401 | 1272 | |
ea8f5fb8 HY |
1273 | #define MEMORY_FAILURE_FIFO_ORDER 4 |
1274 | #define MEMORY_FAILURE_FIFO_SIZE (1 << MEMORY_FAILURE_FIFO_ORDER) | |
1275 | ||
1276 | struct memory_failure_entry { | |
1277 | unsigned long pfn; | |
1278 | int trapno; | |
1279 | int flags; | |
1280 | }; | |
1281 | ||
1282 | struct memory_failure_cpu { | |
1283 | DECLARE_KFIFO(fifo, struct memory_failure_entry, | |
1284 | MEMORY_FAILURE_FIFO_SIZE); | |
1285 | spinlock_t lock; | |
1286 | struct work_struct work; | |
1287 | }; | |
1288 | ||
1289 | static DEFINE_PER_CPU(struct memory_failure_cpu, memory_failure_cpu); | |
1290 | ||
1291 | /** | |
1292 | * memory_failure_queue - Schedule handling memory failure of a page. | |
1293 | * @pfn: Page Number of the corrupted page | |
1294 | * @trapno: Trap number reported in the signal to user space. | |
1295 | * @flags: Flags for memory failure handling | |
1296 | * | |
1297 | * This function is called by the low level hardware error handler | |
1298 | * when it detects hardware memory corruption of a page. It schedules | |
1299 | * the recovering of error page, including dropping pages, killing | |
1300 | * processes etc. | |
1301 | * | |
1302 | * The function is primarily of use for corruptions that | |
1303 | * happen outside the current execution context (e.g. when | |
1304 | * detected by a background scrubber) | |
1305 | * | |
1306 | * Can run in IRQ context. | |
1307 | */ | |
1308 | void memory_failure_queue(unsigned long pfn, int trapno, int flags) | |
1309 | { | |
1310 | struct memory_failure_cpu *mf_cpu; | |
1311 | unsigned long proc_flags; | |
1312 | struct memory_failure_entry entry = { | |
1313 | .pfn = pfn, | |
1314 | .trapno = trapno, | |
1315 | .flags = flags, | |
1316 | }; | |
1317 | ||
1318 | mf_cpu = &get_cpu_var(memory_failure_cpu); | |
1319 | spin_lock_irqsave(&mf_cpu->lock, proc_flags); | |
498d319b | 1320 | if (kfifo_put(&mf_cpu->fifo, entry)) |
ea8f5fb8 HY |
1321 | schedule_work_on(smp_processor_id(), &mf_cpu->work); |
1322 | else | |
8e33a52f | 1323 | pr_err("Memory failure: buffer overflow when queuing memory failure at %#lx\n", |
ea8f5fb8 HY |
1324 | pfn); |
1325 | spin_unlock_irqrestore(&mf_cpu->lock, proc_flags); | |
1326 | put_cpu_var(memory_failure_cpu); | |
1327 | } | |
1328 | EXPORT_SYMBOL_GPL(memory_failure_queue); | |
1329 | ||
1330 | static void memory_failure_work_func(struct work_struct *work) | |
1331 | { | |
1332 | struct memory_failure_cpu *mf_cpu; | |
1333 | struct memory_failure_entry entry = { 0, }; | |
1334 | unsigned long proc_flags; | |
1335 | int gotten; | |
1336 | ||
7c8e0181 | 1337 | mf_cpu = this_cpu_ptr(&memory_failure_cpu); |
ea8f5fb8 HY |
1338 | for (;;) { |
1339 | spin_lock_irqsave(&mf_cpu->lock, proc_flags); | |
1340 | gotten = kfifo_get(&mf_cpu->fifo, &entry); | |
1341 | spin_unlock_irqrestore(&mf_cpu->lock, proc_flags); | |
1342 | if (!gotten) | |
1343 | break; | |
cf870c70 NR |
1344 | if (entry.flags & MF_SOFT_OFFLINE) |
1345 | soft_offline_page(pfn_to_page(entry.pfn), entry.flags); | |
1346 | else | |
1347 | memory_failure(entry.pfn, entry.trapno, entry.flags); | |
ea8f5fb8 HY |
1348 | } |
1349 | } | |
1350 | ||
1351 | static int __init memory_failure_init(void) | |
1352 | { | |
1353 | struct memory_failure_cpu *mf_cpu; | |
1354 | int cpu; | |
1355 | ||
1356 | for_each_possible_cpu(cpu) { | |
1357 | mf_cpu = &per_cpu(memory_failure_cpu, cpu); | |
1358 | spin_lock_init(&mf_cpu->lock); | |
1359 | INIT_KFIFO(mf_cpu->fifo); | |
1360 | INIT_WORK(&mf_cpu->work, memory_failure_work_func); | |
1361 | } | |
1362 | ||
1363 | return 0; | |
1364 | } | |
1365 | core_initcall(memory_failure_init); | |
1366 | ||
a5f65109 NH |
1367 | #define unpoison_pr_info(fmt, pfn, rs) \ |
1368 | ({ \ | |
1369 | if (__ratelimit(rs)) \ | |
1370 | pr_info(fmt, pfn); \ | |
1371 | }) | |
1372 | ||
847ce401 WF |
1373 | /** |
1374 | * unpoison_memory - Unpoison a previously poisoned page | |
1375 | * @pfn: Page number of the to be unpoisoned page | |
1376 | * | |
1377 | * Software-unpoison a page that has been poisoned by | |
1378 | * memory_failure() earlier. | |
1379 | * | |
1380 | * This is only done on the software-level, so it only works | |
1381 | * for linux injected failures, not real hardware failures | |
1382 | * | |
1383 | * Returns 0 for success, otherwise -errno. | |
1384 | */ | |
1385 | int unpoison_memory(unsigned long pfn) | |
1386 | { | |
1387 | struct page *page; | |
1388 | struct page *p; | |
1389 | int freeit = 0; | |
c9fbdd5f | 1390 | unsigned int nr_pages; |
a5f65109 NH |
1391 | static DEFINE_RATELIMIT_STATE(unpoison_rs, DEFAULT_RATELIMIT_INTERVAL, |
1392 | DEFAULT_RATELIMIT_BURST); | |
847ce401 WF |
1393 | |
1394 | if (!pfn_valid(pfn)) | |
1395 | return -ENXIO; | |
1396 | ||
1397 | p = pfn_to_page(pfn); | |
1398 | page = compound_head(p); | |
1399 | ||
1400 | if (!PageHWPoison(p)) { | |
495367c0 | 1401 | unpoison_pr_info("Unpoison: Page was already unpoisoned %#lx\n", |
a5f65109 | 1402 | pfn, &unpoison_rs); |
847ce401 WF |
1403 | return 0; |
1404 | } | |
1405 | ||
230ac719 | 1406 | if (page_count(page) > 1) { |
495367c0 | 1407 | unpoison_pr_info("Unpoison: Someone grabs the hwpoison page %#lx\n", |
a5f65109 | 1408 | pfn, &unpoison_rs); |
230ac719 NH |
1409 | return 0; |
1410 | } | |
1411 | ||
1412 | if (page_mapped(page)) { | |
495367c0 | 1413 | unpoison_pr_info("Unpoison: Someone maps the hwpoison page %#lx\n", |
a5f65109 | 1414 | pfn, &unpoison_rs); |
230ac719 NH |
1415 | return 0; |
1416 | } | |
1417 | ||
1418 | if (page_mapping(page)) { | |
495367c0 | 1419 | unpoison_pr_info("Unpoison: the hwpoison page has non-NULL mapping %#lx\n", |
a5f65109 | 1420 | pfn, &unpoison_rs); |
230ac719 NH |
1421 | return 0; |
1422 | } | |
1423 | ||
0cea3fdc WL |
1424 | /* |
1425 | * unpoison_memory() can encounter thp only when the thp is being | |
1426 | * worked by memory_failure() and the page lock is not held yet. | |
1427 | * In such case, we yield to memory_failure() and make unpoison fail. | |
1428 | */ | |
e76d30e2 | 1429 | if (!PageHuge(page) && PageTransHuge(page)) { |
495367c0 | 1430 | unpoison_pr_info("Unpoison: Memory failure is now running on %#lx\n", |
a5f65109 | 1431 | pfn, &unpoison_rs); |
ead07f6a | 1432 | return 0; |
0cea3fdc WL |
1433 | } |
1434 | ||
f9121153 | 1435 | nr_pages = 1 << compound_order(page); |
c9fbdd5f | 1436 | |
ead07f6a | 1437 | if (!get_hwpoison_page(p)) { |
8c6c2ecb NH |
1438 | /* |
1439 | * Since HWPoisoned hugepage should have non-zero refcount, | |
1440 | * race between memory failure and unpoison seems to happen. | |
1441 | * In such case unpoison fails and memory failure runs | |
1442 | * to the end. | |
1443 | */ | |
1444 | if (PageHuge(page)) { | |
495367c0 | 1445 | unpoison_pr_info("Unpoison: Memory failure is now running on free hugepage %#lx\n", |
a5f65109 | 1446 | pfn, &unpoison_rs); |
8c6c2ecb NH |
1447 | return 0; |
1448 | } | |
847ce401 | 1449 | if (TestClearPageHWPoison(p)) |
8e30456b | 1450 | num_poisoned_pages_dec(); |
495367c0 | 1451 | unpoison_pr_info("Unpoison: Software-unpoisoned free page %#lx\n", |
a5f65109 | 1452 | pfn, &unpoison_rs); |
847ce401 WF |
1453 | return 0; |
1454 | } | |
1455 | ||
7eaceacc | 1456 | lock_page(page); |
847ce401 WF |
1457 | /* |
1458 | * This test is racy because PG_hwpoison is set outside of page lock. | |
1459 | * That's acceptable because that won't trigger kernel panic. Instead, | |
1460 | * the PG_hwpoison page will be caught and isolated on the entrance to | |
1461 | * the free buddy page pool. | |
1462 | */ | |
c9fbdd5f | 1463 | if (TestClearPageHWPoison(page)) { |
495367c0 | 1464 | unpoison_pr_info("Unpoison: Software-unpoisoned page %#lx\n", |
a5f65109 | 1465 | pfn, &unpoison_rs); |
8e30456b | 1466 | num_poisoned_pages_sub(nr_pages); |
847ce401 | 1467 | freeit = 1; |
6a90181c NH |
1468 | if (PageHuge(page)) |
1469 | clear_page_hwpoison_huge_page(page); | |
847ce401 WF |
1470 | } |
1471 | unlock_page(page); | |
1472 | ||
665d9da7 | 1473 | put_hwpoison_page(page); |
3ba5eebc | 1474 | if (freeit && !(pfn == my_zero_pfn(0) && page_count(p) == 1)) |
665d9da7 | 1475 | put_hwpoison_page(page); |
847ce401 WF |
1476 | |
1477 | return 0; | |
1478 | } | |
1479 | EXPORT_SYMBOL(unpoison_memory); | |
facb6011 AK |
1480 | |
1481 | static struct page *new_page(struct page *p, unsigned long private, int **x) | |
1482 | { | |
12686d15 | 1483 | int nid = page_to_nid(p); |
d950b958 NH |
1484 | if (PageHuge(p)) |
1485 | return alloc_huge_page_node(page_hstate(compound_head(p)), | |
1486 | nid); | |
1487 | else | |
96db800f | 1488 | return __alloc_pages_node(nid, GFP_HIGHUSER_MOVABLE, 0); |
facb6011 AK |
1489 | } |
1490 | ||
1491 | /* | |
1492 | * Safely get reference count of an arbitrary page. | |
1493 | * Returns 0 for a free page, -EIO for a zero refcount page | |
1494 | * that is not free, and 1 for any other page type. | |
1495 | * For 1 the page is returned with increased page count, otherwise not. | |
1496 | */ | |
af8fae7c | 1497 | static int __get_any_page(struct page *p, unsigned long pfn, int flags) |
facb6011 AK |
1498 | { |
1499 | int ret; | |
1500 | ||
1501 | if (flags & MF_COUNT_INCREASED) | |
1502 | return 1; | |
1503 | ||
d950b958 NH |
1504 | /* |
1505 | * When the target page is a free hugepage, just remove it | |
1506 | * from free hugepage list. | |
1507 | */ | |
ead07f6a | 1508 | if (!get_hwpoison_page(p)) { |
d950b958 | 1509 | if (PageHuge(p)) { |
71dd0b8a | 1510 | pr_info("%s: %#lx free huge page\n", __func__, pfn); |
af8fae7c | 1511 | ret = 0; |
d950b958 | 1512 | } else if (is_free_buddy_page(p)) { |
71dd0b8a | 1513 | pr_info("%s: %#lx free buddy page\n", __func__, pfn); |
facb6011 AK |
1514 | ret = 0; |
1515 | } else { | |
71dd0b8a BP |
1516 | pr_info("%s: %#lx: unknown zero refcount page type %lx\n", |
1517 | __func__, pfn, p->flags); | |
facb6011 AK |
1518 | ret = -EIO; |
1519 | } | |
1520 | } else { | |
1521 | /* Not a free page */ | |
1522 | ret = 1; | |
1523 | } | |
facb6011 AK |
1524 | return ret; |
1525 | } | |
1526 | ||
af8fae7c NH |
1527 | static int get_any_page(struct page *page, unsigned long pfn, int flags) |
1528 | { | |
1529 | int ret = __get_any_page(page, pfn, flags); | |
1530 | ||
85fbe5d1 YX |
1531 | if (ret == 1 && !PageHuge(page) && |
1532 | !PageLRU(page) && !__PageMovable(page)) { | |
af8fae7c NH |
1533 | /* |
1534 | * Try to free it. | |
1535 | */ | |
665d9da7 | 1536 | put_hwpoison_page(page); |
af8fae7c NH |
1537 | shake_page(page, 1); |
1538 | ||
1539 | /* | |
1540 | * Did it turn free? | |
1541 | */ | |
1542 | ret = __get_any_page(page, pfn, 0); | |
d96b339f | 1543 | if (ret == 1 && !PageLRU(page)) { |
4f32be67 | 1544 | /* Drop page reference which is from __get_any_page() */ |
665d9da7 | 1545 | put_hwpoison_page(page); |
af8fae7c NH |
1546 | pr_info("soft_offline: %#lx: unknown non LRU page type %lx\n", |
1547 | pfn, page->flags); | |
1548 | return -EIO; | |
1549 | } | |
1550 | } | |
1551 | return ret; | |
1552 | } | |
1553 | ||
d950b958 NH |
1554 | static int soft_offline_huge_page(struct page *page, int flags) |
1555 | { | |
1556 | int ret; | |
1557 | unsigned long pfn = page_to_pfn(page); | |
1558 | struct page *hpage = compound_head(page); | |
b8ec1cee | 1559 | LIST_HEAD(pagelist); |
d950b958 | 1560 | |
af8fae7c NH |
1561 | /* |
1562 | * This double-check of PageHWPoison is to avoid the race with | |
1563 | * memory_failure(). See also comment in __soft_offline_page(). | |
1564 | */ | |
1565 | lock_page(hpage); | |
0ebff32c | 1566 | if (PageHWPoison(hpage)) { |
af8fae7c | 1567 | unlock_page(hpage); |
665d9da7 | 1568 | put_hwpoison_page(hpage); |
0ebff32c | 1569 | pr_info("soft offline: %#lx hugepage already poisoned\n", pfn); |
af8fae7c | 1570 | return -EBUSY; |
0ebff32c | 1571 | } |
af8fae7c | 1572 | unlock_page(hpage); |
d950b958 | 1573 | |
bcc54222 | 1574 | ret = isolate_huge_page(hpage, &pagelist); |
03613808 WL |
1575 | /* |
1576 | * get_any_page() and isolate_huge_page() takes a refcount each, | |
1577 | * so need to drop one here. | |
1578 | */ | |
665d9da7 | 1579 | put_hwpoison_page(hpage); |
03613808 | 1580 | if (!ret) { |
bcc54222 NH |
1581 | pr_info("soft offline: %#lx hugepage failed to isolate\n", pfn); |
1582 | return -EBUSY; | |
1583 | } | |
1584 | ||
68711a74 | 1585 | ret = migrate_pages(&pagelist, new_page, NULL, MPOL_MF_MOVE_ALL, |
b8ec1cee | 1586 | MIGRATE_SYNC, MR_MEMORY_FAILURE); |
d950b958 | 1587 | if (ret) { |
dd73e85f DN |
1588 | pr_info("soft offline: %#lx: migration failed %d, type %lx\n", |
1589 | pfn, ret, page->flags); | |
b8ec1cee NH |
1590 | /* |
1591 | * We know that soft_offline_huge_page() tries to migrate | |
1592 | * only one hugepage pointed to by hpage, so we need not | |
1593 | * run through the pagelist here. | |
1594 | */ | |
1595 | putback_active_hugepage(hpage); | |
1596 | if (ret > 0) | |
1597 | ret = -EIO; | |
af8fae7c | 1598 | } else { |
a49ecbcd JW |
1599 | /* overcommit hugetlb page will be freed to buddy */ |
1600 | if (PageHuge(page)) { | |
1601 | set_page_hwpoison_huge_page(hpage); | |
1602 | dequeue_hwpoisoned_huge_page(hpage); | |
8e30456b | 1603 | num_poisoned_pages_add(1 << compound_order(hpage)); |
a49ecbcd JW |
1604 | } else { |
1605 | SetPageHWPoison(page); | |
8e30456b | 1606 | num_poisoned_pages_inc(); |
a49ecbcd | 1607 | } |
d950b958 | 1608 | } |
d950b958 NH |
1609 | return ret; |
1610 | } | |
1611 | ||
af8fae7c NH |
1612 | static int __soft_offline_page(struct page *page, int flags) |
1613 | { | |
1614 | int ret; | |
1615 | unsigned long pfn = page_to_pfn(page); | |
facb6011 | 1616 | |
facb6011 | 1617 | /* |
af8fae7c NH |
1618 | * Check PageHWPoison again inside page lock because PageHWPoison |
1619 | * is set by memory_failure() outside page lock. Note that | |
1620 | * memory_failure() also double-checks PageHWPoison inside page lock, | |
1621 | * so there's no race between soft_offline_page() and memory_failure(). | |
facb6011 | 1622 | */ |
0ebff32c XQ |
1623 | lock_page(page); |
1624 | wait_on_page_writeback(page); | |
af8fae7c NH |
1625 | if (PageHWPoison(page)) { |
1626 | unlock_page(page); | |
665d9da7 | 1627 | put_hwpoison_page(page); |
af8fae7c NH |
1628 | pr_info("soft offline: %#lx page already poisoned\n", pfn); |
1629 | return -EBUSY; | |
1630 | } | |
facb6011 AK |
1631 | /* |
1632 | * Try to invalidate first. This should work for | |
1633 | * non dirty unmapped page cache pages. | |
1634 | */ | |
1635 | ret = invalidate_inode_page(page); | |
1636 | unlock_page(page); | |
facb6011 | 1637 | /* |
facb6011 AK |
1638 | * RED-PEN would be better to keep it isolated here, but we |
1639 | * would need to fix isolation locking first. | |
1640 | */ | |
facb6011 | 1641 | if (ret == 1) { |
665d9da7 | 1642 | put_hwpoison_page(page); |
fb46e735 | 1643 | pr_info("soft_offline: %#lx: invalidated\n", pfn); |
af8fae7c | 1644 | SetPageHWPoison(page); |
8e30456b | 1645 | num_poisoned_pages_inc(); |
af8fae7c | 1646 | return 0; |
facb6011 AK |
1647 | } |
1648 | ||
1649 | /* | |
1650 | * Simple invalidation didn't work. | |
1651 | * Try to migrate to a new page instead. migrate.c | |
1652 | * handles a large number of cases for us. | |
1653 | */ | |
85fbe5d1 YX |
1654 | if (PageLRU(page)) |
1655 | ret = isolate_lru_page(page); | |
1656 | else | |
1657 | ret = isolate_movable_page(page, ISOLATE_UNEVICTABLE); | |
bd486285 KK |
1658 | /* |
1659 | * Drop page reference which is came from get_any_page() | |
1660 | * successful isolate_lru_page() already took another one. | |
1661 | */ | |
665d9da7 | 1662 | put_hwpoison_page(page); |
facb6011 AK |
1663 | if (!ret) { |
1664 | LIST_HEAD(pagelist); | |
85fbe5d1 YX |
1665 | /* |
1666 | * After isolated lru page, the PageLRU will be cleared, | |
1667 | * so use !__PageMovable instead for LRU page's mapping | |
1668 | * cannot have PAGE_MAPPING_MOVABLE. | |
1669 | */ | |
1670 | if (!__PageMovable(page)) | |
1671 | inc_node_page_state(page, NR_ISOLATED_ANON + | |
1672 | page_is_file_cache(page)); | |
facb6011 | 1673 | list_add(&page->lru, &pagelist); |
68711a74 | 1674 | ret = migrate_pages(&pagelist, new_page, NULL, MPOL_MF_MOVE_ALL, |
9c620e2b | 1675 | MIGRATE_SYNC, MR_MEMORY_FAILURE); |
facb6011 | 1676 | if (ret) { |
85fbe5d1 YX |
1677 | if (!list_empty(&pagelist)) |
1678 | putback_movable_pages(&pagelist); | |
59c82b70 | 1679 | |
fb46e735 | 1680 | pr_info("soft offline: %#lx: migration failed %d, type %lx\n", |
facb6011 AK |
1681 | pfn, ret, page->flags); |
1682 | if (ret > 0) | |
1683 | ret = -EIO; | |
1684 | } | |
1685 | } else { | |
fb46e735 | 1686 | pr_info("soft offline: %#lx: isolation failed: %d, page count %d, type %lx\n", |
dd73e85f | 1687 | pfn, ret, page_count(page), page->flags); |
facb6011 | 1688 | } |
facb6011 AK |
1689 | return ret; |
1690 | } | |
86e05773 | 1691 | |
acc14dc4 NH |
1692 | static int soft_offline_in_use_page(struct page *page, int flags) |
1693 | { | |
1694 | int ret; | |
1695 | struct page *hpage = compound_head(page); | |
1696 | ||
1697 | if (!PageHuge(page) && PageTransHuge(hpage)) { | |
1698 | lock_page(hpage); | |
98fd1ef4 NH |
1699 | if (!PageAnon(hpage) || unlikely(split_huge_page(hpage))) { |
1700 | unlock_page(hpage); | |
1701 | if (!PageAnon(hpage)) | |
1702 | pr_info("soft offline: %#lx: non anonymous thp\n", page_to_pfn(page)); | |
1703 | else | |
1704 | pr_info("soft offline: %#lx: thp split failed\n", page_to_pfn(page)); | |
1705 | put_hwpoison_page(hpage); | |
acc14dc4 NH |
1706 | return -EBUSY; |
1707 | } | |
98fd1ef4 | 1708 | unlock_page(hpage); |
acc14dc4 NH |
1709 | get_hwpoison_page(page); |
1710 | put_hwpoison_page(hpage); | |
1711 | } | |
1712 | ||
1713 | if (PageHuge(page)) | |
1714 | ret = soft_offline_huge_page(page, flags); | |
1715 | else | |
1716 | ret = __soft_offline_page(page, flags); | |
1717 | ||
1718 | return ret; | |
1719 | } | |
1720 | ||
1721 | static void soft_offline_free_page(struct page *page) | |
1722 | { | |
1723 | if (PageHuge(page)) { | |
1724 | struct page *hpage = compound_head(page); | |
1725 | ||
1726 | set_page_hwpoison_huge_page(hpage); | |
1727 | if (!dequeue_hwpoisoned_huge_page(hpage)) | |
1728 | num_poisoned_pages_add(1 << compound_order(hpage)); | |
1729 | } else { | |
1730 | if (!TestSetPageHWPoison(page)) | |
1731 | num_poisoned_pages_inc(); | |
1732 | } | |
1733 | } | |
1734 | ||
86e05773 WL |
1735 | /** |
1736 | * soft_offline_page - Soft offline a page. | |
1737 | * @page: page to offline | |
1738 | * @flags: flags. Same as memory_failure(). | |
1739 | * | |
1740 | * Returns 0 on success, otherwise negated errno. | |
1741 | * | |
1742 | * Soft offline a page, by migration or invalidation, | |
1743 | * without killing anything. This is for the case when | |
1744 | * a page is not corrupted yet (so it's still valid to access), | |
1745 | * but has had a number of corrected errors and is better taken | |
1746 | * out. | |
1747 | * | |
1748 | * The actual policy on when to do that is maintained by | |
1749 | * user space. | |
1750 | * | |
1751 | * This should never impact any application or cause data loss, | |
1752 | * however it might take some time. | |
1753 | * | |
1754 | * This is not a 100% solution for all memory, but tries to be | |
1755 | * ``good enough'' for the majority of memory. | |
1756 | */ | |
1757 | int soft_offline_page(struct page *page, int flags) | |
1758 | { | |
1759 | int ret; | |
1760 | unsigned long pfn = page_to_pfn(page); | |
86e05773 WL |
1761 | |
1762 | if (PageHWPoison(page)) { | |
1763 | pr_info("soft offline: %#lx page already poisoned\n", pfn); | |
1e0e635b | 1764 | if (flags & MF_COUNT_INCREASED) |
665d9da7 | 1765 | put_hwpoison_page(page); |
86e05773 WL |
1766 | return -EBUSY; |
1767 | } | |
86e05773 | 1768 | |
bfc8c901 | 1769 | get_online_mems(); |
86e05773 | 1770 | ret = get_any_page(page, pfn, flags); |
bfc8c901 | 1771 | put_online_mems(); |
4e41a30c | 1772 | |
acc14dc4 NH |
1773 | if (ret > 0) |
1774 | ret = soft_offline_in_use_page(page, flags); | |
1775 | else if (ret == 0) | |
1776 | soft_offline_free_page(page); | |
4e41a30c | 1777 | |
86e05773 WL |
1778 | return ret; |
1779 | } |