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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 | 51 | #include <linux/migrate.h> |
facb6011 | 52 | #include <linux/suspend.h> |
5a0e3ad6 | 53 | #include <linux/slab.h> |
bf998156 | 54 | #include <linux/swapops.h> |
7af446a8 | 55 | #include <linux/hugetlb.h> |
20d6c96b | 56 | #include <linux/memory_hotplug.h> |
5db8a73a | 57 | #include <linux/mm_inline.h> |
ea8f5fb8 | 58 | #include <linux/kfifo.h> |
a5f65109 | 59 | #include <linux/ratelimit.h> |
6a46079c | 60 | #include "internal.h" |
97f0b134 | 61 | #include "ras/ras_event.h" |
6a46079c AK |
62 | |
63 | int sysctl_memory_failure_early_kill __read_mostly = 0; | |
64 | ||
65 | int sysctl_memory_failure_recovery __read_mostly = 1; | |
66 | ||
293c07e3 | 67 | atomic_long_t num_poisoned_pages __read_mostly = ATOMIC_LONG_INIT(0); |
6a46079c | 68 | |
27df5068 AK |
69 | #if defined(CONFIG_HWPOISON_INJECT) || defined(CONFIG_HWPOISON_INJECT_MODULE) |
70 | ||
1bfe5feb | 71 | u32 hwpoison_filter_enable = 0; |
7c116f2b WF |
72 | u32 hwpoison_filter_dev_major = ~0U; |
73 | u32 hwpoison_filter_dev_minor = ~0U; | |
478c5ffc WF |
74 | u64 hwpoison_filter_flags_mask; |
75 | u64 hwpoison_filter_flags_value; | |
1bfe5feb | 76 | EXPORT_SYMBOL_GPL(hwpoison_filter_enable); |
7c116f2b WF |
77 | EXPORT_SYMBOL_GPL(hwpoison_filter_dev_major); |
78 | EXPORT_SYMBOL_GPL(hwpoison_filter_dev_minor); | |
478c5ffc WF |
79 | EXPORT_SYMBOL_GPL(hwpoison_filter_flags_mask); |
80 | EXPORT_SYMBOL_GPL(hwpoison_filter_flags_value); | |
7c116f2b WF |
81 | |
82 | static int hwpoison_filter_dev(struct page *p) | |
83 | { | |
84 | struct address_space *mapping; | |
85 | dev_t dev; | |
86 | ||
87 | if (hwpoison_filter_dev_major == ~0U && | |
88 | hwpoison_filter_dev_minor == ~0U) | |
89 | return 0; | |
90 | ||
91 | /* | |
1c80b990 | 92 | * page_mapping() does not accept slab pages. |
7c116f2b WF |
93 | */ |
94 | if (PageSlab(p)) | |
95 | return -EINVAL; | |
96 | ||
97 | mapping = page_mapping(p); | |
98 | if (mapping == NULL || mapping->host == NULL) | |
99 | return -EINVAL; | |
100 | ||
101 | dev = mapping->host->i_sb->s_dev; | |
102 | if (hwpoison_filter_dev_major != ~0U && | |
103 | hwpoison_filter_dev_major != MAJOR(dev)) | |
104 | return -EINVAL; | |
105 | if (hwpoison_filter_dev_minor != ~0U && | |
106 | hwpoison_filter_dev_minor != MINOR(dev)) | |
107 | return -EINVAL; | |
108 | ||
109 | return 0; | |
110 | } | |
111 | ||
478c5ffc WF |
112 | static int hwpoison_filter_flags(struct page *p) |
113 | { | |
114 | if (!hwpoison_filter_flags_mask) | |
115 | return 0; | |
116 | ||
117 | if ((stable_page_flags(p) & hwpoison_filter_flags_mask) == | |
118 | hwpoison_filter_flags_value) | |
119 | return 0; | |
120 | else | |
121 | return -EINVAL; | |
122 | } | |
123 | ||
4fd466eb AK |
124 | /* |
125 | * This allows stress tests to limit test scope to a collection of tasks | |
126 | * by putting them under some memcg. This prevents killing unrelated/important | |
127 | * processes such as /sbin/init. Note that the target task may share clean | |
128 | * pages with init (eg. libc text), which is harmless. If the target task | |
129 | * share _dirty_ pages with another task B, the test scheme must make sure B | |
130 | * is also included in the memcg. At last, due to race conditions this filter | |
131 | * can only guarantee that the page either belongs to the memcg tasks, or is | |
132 | * a freed page. | |
133 | */ | |
94a59fb3 | 134 | #ifdef CONFIG_MEMCG |
4fd466eb AK |
135 | u64 hwpoison_filter_memcg; |
136 | EXPORT_SYMBOL_GPL(hwpoison_filter_memcg); | |
137 | static int hwpoison_filter_task(struct page *p) | |
138 | { | |
4fd466eb AK |
139 | if (!hwpoison_filter_memcg) |
140 | return 0; | |
141 | ||
94a59fb3 | 142 | if (page_cgroup_ino(p) != hwpoison_filter_memcg) |
4fd466eb AK |
143 | return -EINVAL; |
144 | ||
145 | return 0; | |
146 | } | |
147 | #else | |
148 | static int hwpoison_filter_task(struct page *p) { return 0; } | |
149 | #endif | |
150 | ||
7c116f2b WF |
151 | int hwpoison_filter(struct page *p) |
152 | { | |
1bfe5feb HL |
153 | if (!hwpoison_filter_enable) |
154 | return 0; | |
155 | ||
7c116f2b WF |
156 | if (hwpoison_filter_dev(p)) |
157 | return -EINVAL; | |
158 | ||
478c5ffc WF |
159 | if (hwpoison_filter_flags(p)) |
160 | return -EINVAL; | |
161 | ||
4fd466eb AK |
162 | if (hwpoison_filter_task(p)) |
163 | return -EINVAL; | |
164 | ||
7c116f2b WF |
165 | return 0; |
166 | } | |
27df5068 AK |
167 | #else |
168 | int hwpoison_filter(struct page *p) | |
169 | { | |
170 | return 0; | |
171 | } | |
172 | #endif | |
173 | ||
7c116f2b WF |
174 | EXPORT_SYMBOL_GPL(hwpoison_filter); |
175 | ||
6a46079c | 176 | /* |
7329bbeb TL |
177 | * Send all the processes who have the page mapped a signal. |
178 | * ``action optional'' if they are not immediately affected by the error | |
179 | * ``action required'' if error happened in current execution context | |
6a46079c | 180 | */ |
83b57531 | 181 | static int kill_proc(struct task_struct *t, unsigned long addr, |
7329bbeb | 182 | unsigned long pfn, struct page *page, int flags) |
6a46079c | 183 | { |
c0f45555 | 184 | short addr_lsb; |
6a46079c AK |
185 | int ret; |
186 | ||
495367c0 CY |
187 | pr_err("Memory failure: %#lx: Killing %s:%d due to hardware memory corruption\n", |
188 | pfn, t->comm, t->pid); | |
c0f45555 | 189 | addr_lsb = compound_order(compound_head(page)) + PAGE_SHIFT; |
7329bbeb | 190 | |
a70ffcac | 191 | if ((flags & MF_ACTION_REQUIRED) && t->mm == current->mm) { |
c0f45555 EB |
192 | ret = force_sig_mceerr(BUS_MCEERR_AR, (void __user *)addr, |
193 | addr_lsb, current); | |
7329bbeb TL |
194 | } else { |
195 | /* | |
196 | * Don't use force here, it's convenient if the signal | |
197 | * can be temporarily blocked. | |
198 | * This could cause a loop when the user sets SIGBUS | |
199 | * to SIG_IGN, but hopefully no one will do that? | |
200 | */ | |
c0f45555 EB |
201 | ret = send_sig_mceerr(BUS_MCEERR_AO, (void __user *)addr, |
202 | addr_lsb, t); /* synchronous? */ | |
7329bbeb | 203 | } |
6a46079c | 204 | if (ret < 0) |
495367c0 | 205 | pr_info("Memory failure: Error sending signal to %s:%d: %d\n", |
1170532b | 206 | t->comm, t->pid, ret); |
6a46079c AK |
207 | return ret; |
208 | } | |
209 | ||
588f9ce6 AK |
210 | /* |
211 | * When a unknown page type is encountered drain as many buffers as possible | |
212 | * in the hope to turn the page into a LRU or free page, which we can handle. | |
213 | */ | |
facb6011 | 214 | void shake_page(struct page *p, int access) |
588f9ce6 | 215 | { |
8bcb74de NH |
216 | if (PageHuge(p)) |
217 | return; | |
218 | ||
588f9ce6 AK |
219 | if (!PageSlab(p)) { |
220 | lru_add_drain_all(); | |
221 | if (PageLRU(p)) | |
222 | return; | |
c0554329 | 223 | drain_all_pages(page_zone(p)); |
588f9ce6 AK |
224 | if (PageLRU(p) || is_free_buddy_page(p)) |
225 | return; | |
226 | } | |
facb6011 | 227 | |
588f9ce6 | 228 | /* |
6b4f7799 JW |
229 | * Only call shrink_node_slabs here (which would also shrink |
230 | * other caches) if access is not potentially fatal. | |
588f9ce6 | 231 | */ |
cb731d6c VD |
232 | if (access) |
233 | drop_slab_node(page_to_nid(p)); | |
588f9ce6 AK |
234 | } |
235 | EXPORT_SYMBOL_GPL(shake_page); | |
236 | ||
6a46079c AK |
237 | /* |
238 | * Kill all processes that have a poisoned page mapped and then isolate | |
239 | * the page. | |
240 | * | |
241 | * General strategy: | |
242 | * Find all processes having the page mapped and kill them. | |
243 | * But we keep a page reference around so that the page is not | |
244 | * actually freed yet. | |
245 | * Then stash the page away | |
246 | * | |
247 | * There's no convenient way to get back to mapped processes | |
248 | * from the VMAs. So do a brute-force search over all | |
249 | * running processes. | |
250 | * | |
251 | * Remember that machine checks are not common (or rather | |
252 | * if they are common you have other problems), so this shouldn't | |
253 | * be a performance issue. | |
254 | * | |
255 | * Also there are some races possible while we get from the | |
256 | * error detection to actually handle it. | |
257 | */ | |
258 | ||
259 | struct to_kill { | |
260 | struct list_head nd; | |
261 | struct task_struct *tsk; | |
262 | unsigned long addr; | |
9033ae16 | 263 | char addr_valid; |
6a46079c AK |
264 | }; |
265 | ||
266 | /* | |
267 | * Failure handling: if we can't find or can't kill a process there's | |
268 | * not much we can do. We just print a message and ignore otherwise. | |
269 | */ | |
270 | ||
271 | /* | |
272 | * Schedule a process for later kill. | |
273 | * Uses GFP_ATOMIC allocations to avoid potential recursions in the VM. | |
274 | * TBD would GFP_NOIO be enough? | |
275 | */ | |
276 | static void add_to_kill(struct task_struct *tsk, struct page *p, | |
277 | struct vm_area_struct *vma, | |
278 | struct list_head *to_kill, | |
279 | struct to_kill **tkc) | |
280 | { | |
281 | struct to_kill *tk; | |
282 | ||
283 | if (*tkc) { | |
284 | tk = *tkc; | |
285 | *tkc = NULL; | |
286 | } else { | |
287 | tk = kmalloc(sizeof(struct to_kill), GFP_ATOMIC); | |
288 | if (!tk) { | |
495367c0 | 289 | pr_err("Memory failure: Out of memory while machine check handling\n"); |
6a46079c AK |
290 | return; |
291 | } | |
292 | } | |
293 | tk->addr = page_address_in_vma(p, vma); | |
294 | tk->addr_valid = 1; | |
295 | ||
296 | /* | |
297 | * In theory we don't have to kill when the page was | |
298 | * munmaped. But it could be also a mremap. Since that's | |
299 | * likely very rare kill anyways just out of paranoia, but use | |
300 | * a SIGKILL because the error is not contained anymore. | |
301 | */ | |
302 | if (tk->addr == -EFAULT) { | |
495367c0 | 303 | pr_info("Memory failure: Unable to find user space address %lx in %s\n", |
6a46079c AK |
304 | page_to_pfn(p), tsk->comm); |
305 | tk->addr_valid = 0; | |
306 | } | |
307 | get_task_struct(tsk); | |
308 | tk->tsk = tsk; | |
309 | list_add_tail(&tk->nd, to_kill); | |
310 | } | |
311 | ||
312 | /* | |
313 | * Kill the processes that have been collected earlier. | |
314 | * | |
315 | * Only do anything when DOIT is set, otherwise just free the list | |
316 | * (this is used for clean pages which do not need killing) | |
317 | * Also when FAIL is set do a force kill because something went | |
318 | * wrong earlier. | |
319 | */ | |
83b57531 | 320 | static void kill_procs(struct list_head *to_kill, int forcekill, |
666e5a40 | 321 | bool fail, struct page *page, unsigned long pfn, |
7329bbeb | 322 | int flags) |
6a46079c AK |
323 | { |
324 | struct to_kill *tk, *next; | |
325 | ||
326 | list_for_each_entry_safe (tk, next, to_kill, nd) { | |
6751ed65 | 327 | if (forcekill) { |
6a46079c | 328 | /* |
af901ca1 | 329 | * In case something went wrong with munmapping |
6a46079c AK |
330 | * make sure the process doesn't catch the |
331 | * signal and then access the memory. Just kill it. | |
6a46079c AK |
332 | */ |
333 | if (fail || tk->addr_valid == 0) { | |
495367c0 | 334 | pr_err("Memory failure: %#lx: forcibly killing %s:%d because of failure to unmap corrupted page\n", |
1170532b | 335 | pfn, tk->tsk->comm, tk->tsk->pid); |
6a46079c AK |
336 | force_sig(SIGKILL, tk->tsk); |
337 | } | |
338 | ||
339 | /* | |
340 | * In theory the process could have mapped | |
341 | * something else on the address in-between. We could | |
342 | * check for that, but we need to tell the | |
343 | * process anyways. | |
344 | */ | |
83b57531 | 345 | else if (kill_proc(tk->tsk, tk->addr, |
7329bbeb | 346 | pfn, page, flags) < 0) |
495367c0 | 347 | pr_err("Memory failure: %#lx: Cannot send advisory machine check signal to %s:%d\n", |
1170532b | 348 | pfn, tk->tsk->comm, tk->tsk->pid); |
6a46079c AK |
349 | } |
350 | put_task_struct(tk->tsk); | |
351 | kfree(tk); | |
352 | } | |
353 | } | |
354 | ||
3ba08129 NH |
355 | /* |
356 | * Find a dedicated thread which is supposed to handle SIGBUS(BUS_MCEERR_AO) | |
357 | * on behalf of the thread group. Return task_struct of the (first found) | |
358 | * dedicated thread if found, and return NULL otherwise. | |
359 | * | |
360 | * We already hold read_lock(&tasklist_lock) in the caller, so we don't | |
361 | * have to call rcu_read_lock/unlock() in this function. | |
362 | */ | |
363 | static struct task_struct *find_early_kill_thread(struct task_struct *tsk) | |
6a46079c | 364 | { |
3ba08129 NH |
365 | struct task_struct *t; |
366 | ||
367 | for_each_thread(tsk, t) | |
368 | if ((t->flags & PF_MCE_PROCESS) && (t->flags & PF_MCE_EARLY)) | |
369 | return t; | |
370 | return NULL; | |
371 | } | |
372 | ||
373 | /* | |
374 | * Determine whether a given process is "early kill" process which expects | |
375 | * to be signaled when some page under the process is hwpoisoned. | |
376 | * Return task_struct of the dedicated thread (main thread unless explicitly | |
377 | * specified) if the process is "early kill," and otherwise returns NULL. | |
378 | */ | |
379 | static struct task_struct *task_early_kill(struct task_struct *tsk, | |
380 | int force_early) | |
381 | { | |
382 | struct task_struct *t; | |
6a46079c | 383 | if (!tsk->mm) |
3ba08129 | 384 | return NULL; |
74614de1 | 385 | if (force_early) |
3ba08129 NH |
386 | return tsk; |
387 | t = find_early_kill_thread(tsk); | |
388 | if (t) | |
389 | return t; | |
390 | if (sysctl_memory_failure_early_kill) | |
391 | return tsk; | |
392 | return NULL; | |
6a46079c AK |
393 | } |
394 | ||
395 | /* | |
396 | * Collect processes when the error hit an anonymous page. | |
397 | */ | |
398 | static void collect_procs_anon(struct page *page, struct list_head *to_kill, | |
74614de1 | 399 | struct to_kill **tkc, int force_early) |
6a46079c AK |
400 | { |
401 | struct vm_area_struct *vma; | |
402 | struct task_struct *tsk; | |
403 | struct anon_vma *av; | |
bf181b9f | 404 | pgoff_t pgoff; |
6a46079c | 405 | |
4fc3f1d6 | 406 | av = page_lock_anon_vma_read(page); |
6a46079c | 407 | if (av == NULL) /* Not actually mapped anymore */ |
9b679320 PZ |
408 | return; |
409 | ||
a0f7a756 | 410 | pgoff = page_to_pgoff(page); |
9b679320 | 411 | read_lock(&tasklist_lock); |
6a46079c | 412 | for_each_process (tsk) { |
5beb4930 | 413 | struct anon_vma_chain *vmac; |
3ba08129 | 414 | struct task_struct *t = task_early_kill(tsk, force_early); |
5beb4930 | 415 | |
3ba08129 | 416 | if (!t) |
6a46079c | 417 | continue; |
bf181b9f ML |
418 | anon_vma_interval_tree_foreach(vmac, &av->rb_root, |
419 | pgoff, pgoff) { | |
5beb4930 | 420 | vma = vmac->vma; |
6a46079c AK |
421 | if (!page_mapped_in_vma(page, vma)) |
422 | continue; | |
3ba08129 NH |
423 | if (vma->vm_mm == t->mm) |
424 | add_to_kill(t, page, vma, to_kill, tkc); | |
6a46079c AK |
425 | } |
426 | } | |
6a46079c | 427 | read_unlock(&tasklist_lock); |
4fc3f1d6 | 428 | page_unlock_anon_vma_read(av); |
6a46079c AK |
429 | } |
430 | ||
431 | /* | |
432 | * Collect processes when the error hit a file mapped page. | |
433 | */ | |
434 | static void collect_procs_file(struct page *page, struct list_head *to_kill, | |
74614de1 | 435 | struct to_kill **tkc, int force_early) |
6a46079c AK |
436 | { |
437 | struct vm_area_struct *vma; | |
438 | struct task_struct *tsk; | |
6a46079c AK |
439 | struct address_space *mapping = page->mapping; |
440 | ||
d28eb9c8 | 441 | i_mmap_lock_read(mapping); |
9b679320 | 442 | read_lock(&tasklist_lock); |
6a46079c | 443 | for_each_process(tsk) { |
a0f7a756 | 444 | pgoff_t pgoff = page_to_pgoff(page); |
3ba08129 | 445 | struct task_struct *t = task_early_kill(tsk, force_early); |
6a46079c | 446 | |
3ba08129 | 447 | if (!t) |
6a46079c | 448 | continue; |
6b2dbba8 | 449 | vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, |
6a46079c AK |
450 | pgoff) { |
451 | /* | |
452 | * Send early kill signal to tasks where a vma covers | |
453 | * the page but the corrupted page is not necessarily | |
454 | * mapped it in its pte. | |
455 | * Assume applications who requested early kill want | |
456 | * to be informed of all such data corruptions. | |
457 | */ | |
3ba08129 NH |
458 | if (vma->vm_mm == t->mm) |
459 | add_to_kill(t, page, vma, to_kill, tkc); | |
6a46079c AK |
460 | } |
461 | } | |
6a46079c | 462 | read_unlock(&tasklist_lock); |
d28eb9c8 | 463 | i_mmap_unlock_read(mapping); |
6a46079c AK |
464 | } |
465 | ||
466 | /* | |
467 | * Collect the processes who have the corrupted page mapped to kill. | |
468 | * This is done in two steps for locking reasons. | |
469 | * First preallocate one tokill structure outside the spin locks, | |
470 | * so that we can kill at least one process reasonably reliable. | |
471 | */ | |
74614de1 TL |
472 | static void collect_procs(struct page *page, struct list_head *tokill, |
473 | int force_early) | |
6a46079c AK |
474 | { |
475 | struct to_kill *tk; | |
476 | ||
477 | if (!page->mapping) | |
478 | return; | |
479 | ||
480 | tk = kmalloc(sizeof(struct to_kill), GFP_NOIO); | |
481 | if (!tk) | |
482 | return; | |
483 | if (PageAnon(page)) | |
74614de1 | 484 | collect_procs_anon(page, tokill, &tk, force_early); |
6a46079c | 485 | else |
74614de1 | 486 | collect_procs_file(page, tokill, &tk, force_early); |
6a46079c AK |
487 | kfree(tk); |
488 | } | |
489 | ||
6a46079c | 490 | static const char *action_name[] = { |
cc637b17 XX |
491 | [MF_IGNORED] = "Ignored", |
492 | [MF_FAILED] = "Failed", | |
493 | [MF_DELAYED] = "Delayed", | |
494 | [MF_RECOVERED] = "Recovered", | |
64d37a2b NH |
495 | }; |
496 | ||
497 | static const char * const action_page_types[] = { | |
cc637b17 XX |
498 | [MF_MSG_KERNEL] = "reserved kernel page", |
499 | [MF_MSG_KERNEL_HIGH_ORDER] = "high-order kernel page", | |
500 | [MF_MSG_SLAB] = "kernel slab page", | |
501 | [MF_MSG_DIFFERENT_COMPOUND] = "different compound page after locking", | |
502 | [MF_MSG_POISONED_HUGE] = "huge page already hardware poisoned", | |
503 | [MF_MSG_HUGE] = "huge page", | |
504 | [MF_MSG_FREE_HUGE] = "free huge page", | |
31286a84 | 505 | [MF_MSG_NON_PMD_HUGE] = "non-pmd-sized huge page", |
cc637b17 XX |
506 | [MF_MSG_UNMAP_FAILED] = "unmapping failed page", |
507 | [MF_MSG_DIRTY_SWAPCACHE] = "dirty swapcache page", | |
508 | [MF_MSG_CLEAN_SWAPCACHE] = "clean swapcache page", | |
509 | [MF_MSG_DIRTY_MLOCKED_LRU] = "dirty mlocked LRU page", | |
510 | [MF_MSG_CLEAN_MLOCKED_LRU] = "clean mlocked LRU page", | |
511 | [MF_MSG_DIRTY_UNEVICTABLE_LRU] = "dirty unevictable LRU page", | |
512 | [MF_MSG_CLEAN_UNEVICTABLE_LRU] = "clean unevictable LRU page", | |
513 | [MF_MSG_DIRTY_LRU] = "dirty LRU page", | |
514 | [MF_MSG_CLEAN_LRU] = "clean LRU page", | |
515 | [MF_MSG_TRUNCATED_LRU] = "already truncated LRU page", | |
516 | [MF_MSG_BUDDY] = "free buddy page", | |
517 | [MF_MSG_BUDDY_2ND] = "free buddy page (2nd try)", | |
518 | [MF_MSG_UNKNOWN] = "unknown page", | |
64d37a2b NH |
519 | }; |
520 | ||
dc2a1cbf WF |
521 | /* |
522 | * XXX: It is possible that a page is isolated from LRU cache, | |
523 | * and then kept in swap cache or failed to remove from page cache. | |
524 | * The page count will stop it from being freed by unpoison. | |
525 | * Stress tests should be aware of this memory leak problem. | |
526 | */ | |
527 | static int delete_from_lru_cache(struct page *p) | |
528 | { | |
529 | if (!isolate_lru_page(p)) { | |
530 | /* | |
531 | * Clear sensible page flags, so that the buddy system won't | |
532 | * complain when the page is unpoison-and-freed. | |
533 | */ | |
534 | ClearPageActive(p); | |
535 | ClearPageUnevictable(p); | |
18365225 MH |
536 | |
537 | /* | |
538 | * Poisoned page might never drop its ref count to 0 so we have | |
539 | * to uncharge it manually from its memcg. | |
540 | */ | |
541 | mem_cgroup_uncharge(p); | |
542 | ||
dc2a1cbf WF |
543 | /* |
544 | * drop the page count elevated by isolate_lru_page() | |
545 | */ | |
09cbfeaf | 546 | put_page(p); |
dc2a1cbf WF |
547 | return 0; |
548 | } | |
549 | return -EIO; | |
550 | } | |
551 | ||
78bb9203 NH |
552 | static int truncate_error_page(struct page *p, unsigned long pfn, |
553 | struct address_space *mapping) | |
554 | { | |
555 | int ret = MF_FAILED; | |
556 | ||
557 | if (mapping->a_ops->error_remove_page) { | |
558 | int err = mapping->a_ops->error_remove_page(mapping, p); | |
559 | ||
560 | if (err != 0) { | |
561 | pr_info("Memory failure: %#lx: Failed to punch page: %d\n", | |
562 | pfn, err); | |
563 | } else if (page_has_private(p) && | |
564 | !try_to_release_page(p, GFP_NOIO)) { | |
565 | pr_info("Memory failure: %#lx: failed to release buffers\n", | |
566 | pfn); | |
567 | } else { | |
568 | ret = MF_RECOVERED; | |
569 | } | |
570 | } else { | |
571 | /* | |
572 | * If the file system doesn't support it just invalidate | |
573 | * This fails on dirty or anything with private pages | |
574 | */ | |
575 | if (invalidate_inode_page(p)) | |
576 | ret = MF_RECOVERED; | |
577 | else | |
578 | pr_info("Memory failure: %#lx: Failed to invalidate\n", | |
579 | pfn); | |
580 | } | |
581 | ||
582 | return ret; | |
583 | } | |
584 | ||
6a46079c AK |
585 | /* |
586 | * Error hit kernel page. | |
587 | * Do nothing, try to be lucky and not touch this instead. For a few cases we | |
588 | * could be more sophisticated. | |
589 | */ | |
590 | static int me_kernel(struct page *p, unsigned long pfn) | |
6a46079c | 591 | { |
cc637b17 | 592 | return MF_IGNORED; |
6a46079c AK |
593 | } |
594 | ||
595 | /* | |
596 | * Page in unknown state. Do nothing. | |
597 | */ | |
598 | static int me_unknown(struct page *p, unsigned long pfn) | |
599 | { | |
495367c0 | 600 | pr_err("Memory failure: %#lx: Unknown page state\n", pfn); |
cc637b17 | 601 | return MF_FAILED; |
6a46079c AK |
602 | } |
603 | ||
6a46079c AK |
604 | /* |
605 | * Clean (or cleaned) page cache page. | |
606 | */ | |
607 | static int me_pagecache_clean(struct page *p, unsigned long pfn) | |
608 | { | |
6a46079c AK |
609 | struct address_space *mapping; |
610 | ||
dc2a1cbf WF |
611 | delete_from_lru_cache(p); |
612 | ||
6a46079c AK |
613 | /* |
614 | * For anonymous pages we're done the only reference left | |
615 | * should be the one m_f() holds. | |
616 | */ | |
617 | if (PageAnon(p)) | |
cc637b17 | 618 | return MF_RECOVERED; |
6a46079c AK |
619 | |
620 | /* | |
621 | * Now truncate the page in the page cache. This is really | |
622 | * more like a "temporary hole punch" | |
623 | * Don't do this for block devices when someone else | |
624 | * has a reference, because it could be file system metadata | |
625 | * and that's not safe to truncate. | |
626 | */ | |
627 | mapping = page_mapping(p); | |
628 | if (!mapping) { | |
629 | /* | |
630 | * Page has been teared down in the meanwhile | |
631 | */ | |
cc637b17 | 632 | return MF_FAILED; |
6a46079c AK |
633 | } |
634 | ||
635 | /* | |
636 | * Truncation is a bit tricky. Enable it per file system for now. | |
637 | * | |
638 | * Open: to take i_mutex or not for this? Right now we don't. | |
639 | */ | |
78bb9203 | 640 | return truncate_error_page(p, pfn, mapping); |
6a46079c AK |
641 | } |
642 | ||
643 | /* | |
549543df | 644 | * Dirty pagecache page |
6a46079c AK |
645 | * Issues: when the error hit a hole page the error is not properly |
646 | * propagated. | |
647 | */ | |
648 | static int me_pagecache_dirty(struct page *p, unsigned long pfn) | |
649 | { | |
650 | struct address_space *mapping = page_mapping(p); | |
651 | ||
652 | SetPageError(p); | |
653 | /* TBD: print more information about the file. */ | |
654 | if (mapping) { | |
655 | /* | |
656 | * IO error will be reported by write(), fsync(), etc. | |
657 | * who check the mapping. | |
658 | * This way the application knows that something went | |
659 | * wrong with its dirty file data. | |
660 | * | |
661 | * There's one open issue: | |
662 | * | |
663 | * The EIO will be only reported on the next IO | |
664 | * operation and then cleared through the IO map. | |
665 | * Normally Linux has two mechanisms to pass IO error | |
666 | * first through the AS_EIO flag in the address space | |
667 | * and then through the PageError flag in the page. | |
668 | * Since we drop pages on memory failure handling the | |
669 | * only mechanism open to use is through AS_AIO. | |
670 | * | |
671 | * This has the disadvantage that it gets cleared on | |
672 | * the first operation that returns an error, while | |
673 | * the PageError bit is more sticky and only cleared | |
674 | * when the page is reread or dropped. If an | |
675 | * application assumes it will always get error on | |
676 | * fsync, but does other operations on the fd before | |
25985edc | 677 | * and the page is dropped between then the error |
6a46079c AK |
678 | * will not be properly reported. |
679 | * | |
680 | * This can already happen even without hwpoisoned | |
681 | * pages: first on metadata IO errors (which only | |
682 | * report through AS_EIO) or when the page is dropped | |
683 | * at the wrong time. | |
684 | * | |
685 | * So right now we assume that the application DTRT on | |
686 | * the first EIO, but we're not worse than other parts | |
687 | * of the kernel. | |
688 | */ | |
af21bfaf | 689 | mapping_set_error(mapping, -EIO); |
6a46079c AK |
690 | } |
691 | ||
692 | return me_pagecache_clean(p, pfn); | |
693 | } | |
694 | ||
695 | /* | |
696 | * Clean and dirty swap cache. | |
697 | * | |
698 | * Dirty swap cache page is tricky to handle. The page could live both in page | |
699 | * cache and swap cache(ie. page is freshly swapped in). So it could be | |
700 | * referenced concurrently by 2 types of PTEs: | |
701 | * normal PTEs and swap PTEs. We try to handle them consistently by calling | |
702 | * try_to_unmap(TTU_IGNORE_HWPOISON) to convert the normal PTEs to swap PTEs, | |
703 | * and then | |
704 | * - clear dirty bit to prevent IO | |
705 | * - remove from LRU | |
706 | * - but keep in the swap cache, so that when we return to it on | |
707 | * a later page fault, we know the application is accessing | |
708 | * corrupted data and shall be killed (we installed simple | |
709 | * interception code in do_swap_page to catch it). | |
710 | * | |
711 | * Clean swap cache pages can be directly isolated. A later page fault will | |
712 | * bring in the known good data from disk. | |
713 | */ | |
714 | static int me_swapcache_dirty(struct page *p, unsigned long pfn) | |
715 | { | |
6a46079c AK |
716 | ClearPageDirty(p); |
717 | /* Trigger EIO in shmem: */ | |
718 | ClearPageUptodate(p); | |
719 | ||
dc2a1cbf | 720 | if (!delete_from_lru_cache(p)) |
cc637b17 | 721 | return MF_DELAYED; |
dc2a1cbf | 722 | else |
cc637b17 | 723 | return MF_FAILED; |
6a46079c AK |
724 | } |
725 | ||
726 | static int me_swapcache_clean(struct page *p, unsigned long pfn) | |
727 | { | |
6a46079c | 728 | delete_from_swap_cache(p); |
e43c3afb | 729 | |
dc2a1cbf | 730 | if (!delete_from_lru_cache(p)) |
cc637b17 | 731 | return MF_RECOVERED; |
dc2a1cbf | 732 | else |
cc637b17 | 733 | return MF_FAILED; |
6a46079c AK |
734 | } |
735 | ||
736 | /* | |
737 | * Huge pages. Needs work. | |
738 | * Issues: | |
93f70f90 NH |
739 | * - Error on hugepage is contained in hugepage unit (not in raw page unit.) |
740 | * To narrow down kill region to one page, we need to break up pmd. | |
6a46079c AK |
741 | */ |
742 | static int me_huge_page(struct page *p, unsigned long pfn) | |
743 | { | |
6de2b1aa | 744 | int res = 0; |
93f70f90 | 745 | struct page *hpage = compound_head(p); |
78bb9203 | 746 | struct address_space *mapping; |
2491ffee NH |
747 | |
748 | if (!PageHuge(hpage)) | |
749 | return MF_DELAYED; | |
750 | ||
78bb9203 NH |
751 | mapping = page_mapping(hpage); |
752 | if (mapping) { | |
753 | res = truncate_error_page(hpage, pfn, mapping); | |
754 | } else { | |
755 | unlock_page(hpage); | |
756 | /* | |
757 | * migration entry prevents later access on error anonymous | |
758 | * hugepage, so we can free and dissolve it into buddy to | |
759 | * save healthy subpages. | |
760 | */ | |
761 | if (PageAnon(hpage)) | |
762 | put_page(hpage); | |
763 | dissolve_free_huge_page(p); | |
764 | res = MF_RECOVERED; | |
765 | lock_page(hpage); | |
93f70f90 | 766 | } |
78bb9203 NH |
767 | |
768 | return res; | |
6a46079c AK |
769 | } |
770 | ||
771 | /* | |
772 | * Various page states we can handle. | |
773 | * | |
774 | * A page state is defined by its current page->flags bits. | |
775 | * The table matches them in order and calls the right handler. | |
776 | * | |
777 | * This is quite tricky because we can access page at any time | |
25985edc | 778 | * in its live cycle, so all accesses have to be extremely careful. |
6a46079c AK |
779 | * |
780 | * This is not complete. More states could be added. | |
781 | * For any missing state don't attempt recovery. | |
782 | */ | |
783 | ||
784 | #define dirty (1UL << PG_dirty) | |
6326fec1 | 785 | #define sc ((1UL << PG_swapcache) | (1UL << PG_swapbacked)) |
6a46079c AK |
786 | #define unevict (1UL << PG_unevictable) |
787 | #define mlock (1UL << PG_mlocked) | |
788 | #define writeback (1UL << PG_writeback) | |
789 | #define lru (1UL << PG_lru) | |
6a46079c | 790 | #define head (1UL << PG_head) |
6a46079c | 791 | #define slab (1UL << PG_slab) |
6a46079c AK |
792 | #define reserved (1UL << PG_reserved) |
793 | ||
794 | static struct page_state { | |
795 | unsigned long mask; | |
796 | unsigned long res; | |
cc637b17 | 797 | enum mf_action_page_type type; |
6a46079c AK |
798 | int (*action)(struct page *p, unsigned long pfn); |
799 | } error_states[] = { | |
cc637b17 | 800 | { reserved, reserved, MF_MSG_KERNEL, me_kernel }, |
95d01fc6 WF |
801 | /* |
802 | * free pages are specially detected outside this table: | |
803 | * PG_buddy pages only make a small fraction of all free pages. | |
804 | */ | |
6a46079c AK |
805 | |
806 | /* | |
807 | * Could in theory check if slab page is free or if we can drop | |
808 | * currently unused objects without touching them. But just | |
809 | * treat it as standard kernel for now. | |
810 | */ | |
cc637b17 | 811 | { slab, slab, MF_MSG_SLAB, me_kernel }, |
6a46079c | 812 | |
cc637b17 | 813 | { head, head, MF_MSG_HUGE, me_huge_page }, |
6a46079c | 814 | |
cc637b17 XX |
815 | { sc|dirty, sc|dirty, MF_MSG_DIRTY_SWAPCACHE, me_swapcache_dirty }, |
816 | { sc|dirty, sc, MF_MSG_CLEAN_SWAPCACHE, me_swapcache_clean }, | |
6a46079c | 817 | |
cc637b17 XX |
818 | { mlock|dirty, mlock|dirty, MF_MSG_DIRTY_MLOCKED_LRU, me_pagecache_dirty }, |
819 | { mlock|dirty, mlock, MF_MSG_CLEAN_MLOCKED_LRU, me_pagecache_clean }, | |
6a46079c | 820 | |
cc637b17 XX |
821 | { unevict|dirty, unevict|dirty, MF_MSG_DIRTY_UNEVICTABLE_LRU, me_pagecache_dirty }, |
822 | { unevict|dirty, unevict, MF_MSG_CLEAN_UNEVICTABLE_LRU, me_pagecache_clean }, | |
5f4b9fc5 | 823 | |
cc637b17 XX |
824 | { lru|dirty, lru|dirty, MF_MSG_DIRTY_LRU, me_pagecache_dirty }, |
825 | { lru|dirty, lru, MF_MSG_CLEAN_LRU, me_pagecache_clean }, | |
6a46079c AK |
826 | |
827 | /* | |
828 | * Catchall entry: must be at end. | |
829 | */ | |
cc637b17 | 830 | { 0, 0, MF_MSG_UNKNOWN, me_unknown }, |
6a46079c AK |
831 | }; |
832 | ||
2326c467 AK |
833 | #undef dirty |
834 | #undef sc | |
835 | #undef unevict | |
836 | #undef mlock | |
837 | #undef writeback | |
838 | #undef lru | |
2326c467 | 839 | #undef head |
2326c467 AK |
840 | #undef slab |
841 | #undef reserved | |
842 | ||
ff604cf6 NH |
843 | /* |
844 | * "Dirty/Clean" indication is not 100% accurate due to the possibility of | |
845 | * setting PG_dirty outside page lock. See also comment above set_page_dirty(). | |
846 | */ | |
cc3e2af4 XX |
847 | static void action_result(unsigned long pfn, enum mf_action_page_type type, |
848 | enum mf_result result) | |
6a46079c | 849 | { |
97f0b134 XX |
850 | trace_memory_failure_event(pfn, type, result); |
851 | ||
495367c0 | 852 | pr_err("Memory failure: %#lx: recovery action for %s: %s\n", |
64d37a2b | 853 | pfn, action_page_types[type], action_name[result]); |
6a46079c AK |
854 | } |
855 | ||
856 | static int page_action(struct page_state *ps, struct page *p, | |
bd1ce5f9 | 857 | unsigned long pfn) |
6a46079c AK |
858 | { |
859 | int result; | |
7456b040 | 860 | int count; |
6a46079c AK |
861 | |
862 | result = ps->action(p, pfn); | |
7456b040 | 863 | |
bd1ce5f9 | 864 | count = page_count(p) - 1; |
cc637b17 | 865 | if (ps->action == me_swapcache_dirty && result == MF_DELAYED) |
138ce286 | 866 | count--; |
78bb9203 | 867 | if (count > 0) { |
495367c0 | 868 | pr_err("Memory failure: %#lx: %s still referenced by %d users\n", |
64d37a2b | 869 | pfn, action_page_types[ps->type], count); |
cc637b17 | 870 | result = MF_FAILED; |
138ce286 | 871 | } |
64d37a2b | 872 | action_result(pfn, ps->type, result); |
6a46079c AK |
873 | |
874 | /* Could do more checks here if page looks ok */ | |
875 | /* | |
876 | * Could adjust zone counters here to correct for the missing page. | |
877 | */ | |
878 | ||
cc637b17 | 879 | return (result == MF_RECOVERED || result == MF_DELAYED) ? 0 : -EBUSY; |
6a46079c AK |
880 | } |
881 | ||
ead07f6a NH |
882 | /** |
883 | * get_hwpoison_page() - Get refcount for memory error handling: | |
884 | * @page: raw error page (hit by memory error) | |
885 | * | |
886 | * Return: return 0 if failed to grab the refcount, otherwise true (some | |
887 | * non-zero value.) | |
888 | */ | |
889 | int get_hwpoison_page(struct page *page) | |
890 | { | |
891 | struct page *head = compound_head(page); | |
892 | ||
4e41a30c | 893 | if (!PageHuge(head) && PageTransHuge(head)) { |
98ed2b00 NH |
894 | /* |
895 | * Non anonymous thp exists only in allocation/free time. We | |
896 | * can't handle such a case correctly, so let's give it up. | |
897 | * This should be better than triggering BUG_ON when kernel | |
898 | * tries to touch the "partially handled" page. | |
899 | */ | |
900 | if (!PageAnon(head)) { | |
495367c0 | 901 | pr_err("Memory failure: %#lx: non anonymous thp\n", |
98ed2b00 NH |
902 | page_to_pfn(page)); |
903 | return 0; | |
904 | } | |
ead07f6a NH |
905 | } |
906 | ||
c2e7e00b KK |
907 | if (get_page_unless_zero(head)) { |
908 | if (head == compound_head(page)) | |
909 | return 1; | |
910 | ||
495367c0 CY |
911 | pr_info("Memory failure: %#lx cannot catch tail\n", |
912 | page_to_pfn(page)); | |
c2e7e00b KK |
913 | put_page(head); |
914 | } | |
915 | ||
916 | return 0; | |
ead07f6a NH |
917 | } |
918 | EXPORT_SYMBOL_GPL(get_hwpoison_page); | |
919 | ||
6a46079c AK |
920 | /* |
921 | * Do all that is necessary to remove user space mappings. Unmap | |
922 | * the pages and send SIGBUS to the processes if the data was dirty. | |
923 | */ | |
666e5a40 | 924 | static bool hwpoison_user_mappings(struct page *p, unsigned long pfn, |
83b57531 | 925 | int flags, struct page **hpagep) |
6a46079c | 926 | { |
a128ca71 | 927 | enum ttu_flags ttu = TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS; |
6a46079c AK |
928 | struct address_space *mapping; |
929 | LIST_HEAD(tokill); | |
666e5a40 | 930 | bool unmap_success; |
6751ed65 | 931 | int kill = 1, forcekill; |
54b9dd14 | 932 | struct page *hpage = *hpagep; |
286c469a | 933 | bool mlocked = PageMlocked(hpage); |
6a46079c | 934 | |
93a9eb39 NH |
935 | /* |
936 | * Here we are interested only in user-mapped pages, so skip any | |
937 | * other types of pages. | |
938 | */ | |
939 | if (PageReserved(p) || PageSlab(p)) | |
666e5a40 | 940 | return true; |
93a9eb39 | 941 | if (!(PageLRU(hpage) || PageHuge(p))) |
666e5a40 | 942 | return true; |
6a46079c | 943 | |
6a46079c AK |
944 | /* |
945 | * This check implies we don't kill processes if their pages | |
946 | * are in the swap cache early. Those are always late kills. | |
947 | */ | |
7af446a8 | 948 | if (!page_mapped(hpage)) |
666e5a40 | 949 | return true; |
1668bfd5 | 950 | |
52089b14 | 951 | if (PageKsm(p)) { |
495367c0 | 952 | pr_err("Memory failure: %#lx: can't handle KSM pages.\n", pfn); |
666e5a40 | 953 | return false; |
52089b14 | 954 | } |
6a46079c AK |
955 | |
956 | if (PageSwapCache(p)) { | |
495367c0 CY |
957 | pr_err("Memory failure: %#lx: keeping poisoned page in swap cache\n", |
958 | pfn); | |
6a46079c AK |
959 | ttu |= TTU_IGNORE_HWPOISON; |
960 | } | |
961 | ||
962 | /* | |
963 | * Propagate the dirty bit from PTEs to struct page first, because we | |
964 | * need this to decide if we should kill or just drop the page. | |
db0480b3 WF |
965 | * XXX: the dirty test could be racy: set_page_dirty() may not always |
966 | * be called inside page lock (it's recommended but not enforced). | |
6a46079c | 967 | */ |
7af446a8 | 968 | mapping = page_mapping(hpage); |
6751ed65 | 969 | if (!(flags & MF_MUST_KILL) && !PageDirty(hpage) && mapping && |
7af446a8 NH |
970 | mapping_cap_writeback_dirty(mapping)) { |
971 | if (page_mkclean(hpage)) { | |
972 | SetPageDirty(hpage); | |
6a46079c AK |
973 | } else { |
974 | kill = 0; | |
975 | ttu |= TTU_IGNORE_HWPOISON; | |
495367c0 | 976 | pr_info("Memory failure: %#lx: corrupted page was clean: dropped without side effects\n", |
6a46079c AK |
977 | pfn); |
978 | } | |
979 | } | |
980 | ||
981 | /* | |
982 | * First collect all the processes that have the page | |
983 | * mapped in dirty form. This has to be done before try_to_unmap, | |
984 | * because ttu takes the rmap data structures down. | |
985 | * | |
986 | * Error handling: We ignore errors here because | |
987 | * there's nothing that can be done. | |
988 | */ | |
989 | if (kill) | |
415c64c1 | 990 | collect_procs(hpage, &tokill, flags & MF_ACTION_REQUIRED); |
6a46079c | 991 | |
666e5a40 MK |
992 | unmap_success = try_to_unmap(hpage, ttu); |
993 | if (!unmap_success) | |
495367c0 | 994 | pr_err("Memory failure: %#lx: failed to unmap page (mapcount=%d)\n", |
1170532b | 995 | pfn, page_mapcount(hpage)); |
a6d30ddd | 996 | |
286c469a NH |
997 | /* |
998 | * try_to_unmap() might put mlocked page in lru cache, so call | |
999 | * shake_page() again to ensure that it's flushed. | |
1000 | */ | |
1001 | if (mlocked) | |
1002 | shake_page(hpage, 0); | |
1003 | ||
6a46079c AK |
1004 | /* |
1005 | * Now that the dirty bit has been propagated to the | |
1006 | * struct page and all unmaps done we can decide if | |
1007 | * killing is needed or not. Only kill when the page | |
6751ed65 TL |
1008 | * was dirty or the process is not restartable, |
1009 | * otherwise the tokill list is merely | |
6a46079c AK |
1010 | * freed. When there was a problem unmapping earlier |
1011 | * use a more force-full uncatchable kill to prevent | |
1012 | * any accesses to the poisoned memory. | |
1013 | */ | |
415c64c1 | 1014 | forcekill = PageDirty(hpage) || (flags & MF_MUST_KILL); |
83b57531 | 1015 | kill_procs(&tokill, forcekill, !unmap_success, p, pfn, flags); |
1668bfd5 | 1016 | |
666e5a40 | 1017 | return unmap_success; |
6a46079c AK |
1018 | } |
1019 | ||
0348d2eb NH |
1020 | static int identify_page_state(unsigned long pfn, struct page *p, |
1021 | unsigned long page_flags) | |
761ad8d7 NH |
1022 | { |
1023 | struct page_state *ps; | |
0348d2eb NH |
1024 | |
1025 | /* | |
1026 | * The first check uses the current page flags which may not have any | |
1027 | * relevant information. The second check with the saved page flags is | |
1028 | * carried out only if the first check can't determine the page status. | |
1029 | */ | |
1030 | for (ps = error_states;; ps++) | |
1031 | if ((p->flags & ps->mask) == ps->res) | |
1032 | break; | |
1033 | ||
1034 | page_flags |= (p->flags & (1UL << PG_dirty)); | |
1035 | ||
1036 | if (!ps->mask) | |
1037 | for (ps = error_states;; ps++) | |
1038 | if ((page_flags & ps->mask) == ps->res) | |
1039 | break; | |
1040 | return page_action(ps, p, pfn); | |
1041 | } | |
1042 | ||
83b57531 | 1043 | static int memory_failure_hugetlb(unsigned long pfn, int flags) |
0348d2eb | 1044 | { |
761ad8d7 NH |
1045 | struct page *p = pfn_to_page(pfn); |
1046 | struct page *head = compound_head(p); | |
1047 | int res; | |
1048 | unsigned long page_flags; | |
1049 | ||
1050 | if (TestSetPageHWPoison(head)) { | |
1051 | pr_err("Memory failure: %#lx: already hardware poisoned\n", | |
1052 | pfn); | |
1053 | return 0; | |
1054 | } | |
1055 | ||
1056 | num_poisoned_pages_inc(); | |
1057 | ||
1058 | if (!(flags & MF_COUNT_INCREASED) && !get_hwpoison_page(p)) { | |
1059 | /* | |
1060 | * Check "filter hit" and "race with other subpage." | |
1061 | */ | |
1062 | lock_page(head); | |
1063 | if (PageHWPoison(head)) { | |
1064 | if ((hwpoison_filter(p) && TestClearPageHWPoison(p)) | |
1065 | || (p != head && TestSetPageHWPoison(head))) { | |
1066 | num_poisoned_pages_dec(); | |
1067 | unlock_page(head); | |
1068 | return 0; | |
1069 | } | |
1070 | } | |
1071 | unlock_page(head); | |
1072 | dissolve_free_huge_page(p); | |
1073 | action_result(pfn, MF_MSG_FREE_HUGE, MF_DELAYED); | |
1074 | return 0; | |
1075 | } | |
1076 | ||
1077 | lock_page(head); | |
1078 | page_flags = head->flags; | |
1079 | ||
1080 | if (!PageHWPoison(head)) { | |
1081 | pr_err("Memory failure: %#lx: just unpoisoned\n", pfn); | |
1082 | num_poisoned_pages_dec(); | |
1083 | unlock_page(head); | |
1084 | put_hwpoison_page(head); | |
1085 | return 0; | |
1086 | } | |
1087 | ||
31286a84 NH |
1088 | /* |
1089 | * TODO: hwpoison for pud-sized hugetlb doesn't work right now, so | |
1090 | * simply disable it. In order to make it work properly, we need | |
1091 | * make sure that: | |
1092 | * - conversion of a pud that maps an error hugetlb into hwpoison | |
1093 | * entry properly works, and | |
1094 | * - other mm code walking over page table is aware of pud-aligned | |
1095 | * hwpoison entries. | |
1096 | */ | |
1097 | if (huge_page_size(page_hstate(head)) > PMD_SIZE) { | |
1098 | action_result(pfn, MF_MSG_NON_PMD_HUGE, MF_IGNORED); | |
1099 | res = -EBUSY; | |
1100 | goto out; | |
1101 | } | |
1102 | ||
83b57531 | 1103 | if (!hwpoison_user_mappings(p, pfn, flags, &head)) { |
761ad8d7 NH |
1104 | action_result(pfn, MF_MSG_UNMAP_FAILED, MF_IGNORED); |
1105 | res = -EBUSY; | |
1106 | goto out; | |
1107 | } | |
1108 | ||
0348d2eb | 1109 | res = identify_page_state(pfn, p, page_flags); |
761ad8d7 NH |
1110 | out: |
1111 | unlock_page(head); | |
1112 | return res; | |
1113 | } | |
1114 | ||
cd42f4a3 TL |
1115 | /** |
1116 | * memory_failure - Handle memory failure of a page. | |
1117 | * @pfn: Page Number of the corrupted page | |
cd42f4a3 TL |
1118 | * @flags: fine tune action taken |
1119 | * | |
1120 | * This function is called by the low level machine check code | |
1121 | * of an architecture when it detects hardware memory corruption | |
1122 | * of a page. It tries its best to recover, which includes | |
1123 | * dropping pages, killing processes etc. | |
1124 | * | |
1125 | * The function is primarily of use for corruptions that | |
1126 | * happen outside the current execution context (e.g. when | |
1127 | * detected by a background scrubber) | |
1128 | * | |
1129 | * Must run in process context (e.g. a work queue) with interrupts | |
1130 | * enabled and no spinlocks hold. | |
1131 | */ | |
83b57531 | 1132 | int memory_failure(unsigned long pfn, int flags) |
6a46079c | 1133 | { |
6a46079c | 1134 | struct page *p; |
7af446a8 | 1135 | struct page *hpage; |
415c64c1 | 1136 | struct page *orig_head; |
6a46079c | 1137 | int res; |
524fca1e | 1138 | unsigned long page_flags; |
6a46079c AK |
1139 | |
1140 | if (!sysctl_memory_failure_recovery) | |
83b57531 | 1141 | panic("Memory failure on page %lx", pfn); |
6a46079c AK |
1142 | |
1143 | if (!pfn_valid(pfn)) { | |
495367c0 CY |
1144 | pr_err("Memory failure: %#lx: memory outside kernel control\n", |
1145 | pfn); | |
a7560fc8 | 1146 | return -ENXIO; |
6a46079c AK |
1147 | } |
1148 | ||
1149 | p = pfn_to_page(pfn); | |
761ad8d7 | 1150 | if (PageHuge(p)) |
83b57531 | 1151 | return memory_failure_hugetlb(pfn, flags); |
6a46079c | 1152 | if (TestSetPageHWPoison(p)) { |
495367c0 CY |
1153 | pr_err("Memory failure: %#lx: already hardware poisoned\n", |
1154 | pfn); | |
6a46079c AK |
1155 | return 0; |
1156 | } | |
1157 | ||
761ad8d7 | 1158 | orig_head = hpage = compound_head(p); |
b37ff71c | 1159 | num_poisoned_pages_inc(); |
6a46079c AK |
1160 | |
1161 | /* | |
1162 | * We need/can do nothing about count=0 pages. | |
1163 | * 1) it's a free page, and therefore in safe hand: | |
1164 | * prep_new_page() will be the gate keeper. | |
761ad8d7 | 1165 | * 2) it's part of a non-compound high order page. |
6a46079c AK |
1166 | * Implies some kernel user: cannot stop them from |
1167 | * R/W the page; let's pray that the page has been | |
1168 | * used and will be freed some time later. | |
1169 | * In fact it's dangerous to directly bump up page count from 0, | |
1170 | * that may make page_freeze_refs()/page_unfreeze_refs() mismatch. | |
1171 | */ | |
ead07f6a | 1172 | if (!(flags & MF_COUNT_INCREASED) && !get_hwpoison_page(p)) { |
8d22ba1b | 1173 | if (is_free_buddy_page(p)) { |
cc637b17 | 1174 | action_result(pfn, MF_MSG_BUDDY, MF_DELAYED); |
8d22ba1b WF |
1175 | return 0; |
1176 | } else { | |
cc637b17 | 1177 | action_result(pfn, MF_MSG_KERNEL_HIGH_ORDER, MF_IGNORED); |
8d22ba1b WF |
1178 | return -EBUSY; |
1179 | } | |
6a46079c AK |
1180 | } |
1181 | ||
761ad8d7 | 1182 | if (PageTransHuge(hpage)) { |
c3901e72 NH |
1183 | lock_page(p); |
1184 | if (!PageAnon(p) || unlikely(split_huge_page(p))) { | |
1185 | unlock_page(p); | |
1186 | if (!PageAnon(p)) | |
495367c0 CY |
1187 | pr_err("Memory failure: %#lx: non anonymous thp\n", |
1188 | pfn); | |
7f6bf39b | 1189 | else |
495367c0 CY |
1190 | pr_err("Memory failure: %#lx: thp split failed\n", |
1191 | pfn); | |
ead07f6a | 1192 | if (TestClearPageHWPoison(p)) |
b37ff71c | 1193 | num_poisoned_pages_dec(); |
665d9da7 | 1194 | put_hwpoison_page(p); |
415c64c1 NH |
1195 | return -EBUSY; |
1196 | } | |
c3901e72 | 1197 | unlock_page(p); |
415c64c1 NH |
1198 | VM_BUG_ON_PAGE(!page_count(p), p); |
1199 | hpage = compound_head(p); | |
1200 | } | |
1201 | ||
e43c3afb WF |
1202 | /* |
1203 | * We ignore non-LRU pages for good reasons. | |
1204 | * - PG_locked is only well defined for LRU pages and a few others | |
48c935ad | 1205 | * - to avoid races with __SetPageLocked() |
e43c3afb WF |
1206 | * - to avoid races with __SetPageSlab*() (and more non-atomic ops) |
1207 | * The check (unnecessarily) ignores LRU pages being isolated and | |
1208 | * walked by the page reclaim code, however that's not a big loss. | |
1209 | */ | |
8bcb74de NH |
1210 | shake_page(p, 0); |
1211 | /* shake_page could have turned it free. */ | |
1212 | if (!PageLRU(p) && is_free_buddy_page(p)) { | |
1213 | if (flags & MF_COUNT_INCREASED) | |
1214 | action_result(pfn, MF_MSG_BUDDY, MF_DELAYED); | |
1215 | else | |
1216 | action_result(pfn, MF_MSG_BUDDY_2ND, MF_DELAYED); | |
1217 | return 0; | |
e43c3afb | 1218 | } |
e43c3afb | 1219 | |
761ad8d7 | 1220 | lock_page(p); |
847ce401 | 1221 | |
f37d4298 AK |
1222 | /* |
1223 | * The page could have changed compound pages during the locking. | |
1224 | * If this happens just bail out. | |
1225 | */ | |
415c64c1 | 1226 | if (PageCompound(p) && compound_head(p) != orig_head) { |
cc637b17 | 1227 | action_result(pfn, MF_MSG_DIFFERENT_COMPOUND, MF_IGNORED); |
f37d4298 AK |
1228 | res = -EBUSY; |
1229 | goto out; | |
1230 | } | |
1231 | ||
524fca1e NH |
1232 | /* |
1233 | * We use page flags to determine what action should be taken, but | |
1234 | * the flags can be modified by the error containment action. One | |
1235 | * example is an mlocked page, where PG_mlocked is cleared by | |
1236 | * page_remove_rmap() in try_to_unmap_one(). So to determine page status | |
1237 | * correctly, we save a copy of the page flags at this time. | |
1238 | */ | |
7258ae5c JM |
1239 | if (PageHuge(p)) |
1240 | page_flags = hpage->flags; | |
1241 | else | |
1242 | page_flags = p->flags; | |
524fca1e | 1243 | |
847ce401 WF |
1244 | /* |
1245 | * unpoison always clear PG_hwpoison inside page lock | |
1246 | */ | |
1247 | if (!PageHWPoison(p)) { | |
495367c0 | 1248 | pr_err("Memory failure: %#lx: just unpoisoned\n", pfn); |
b37ff71c | 1249 | num_poisoned_pages_dec(); |
761ad8d7 NH |
1250 | unlock_page(p); |
1251 | put_hwpoison_page(p); | |
a09233f3 | 1252 | return 0; |
847ce401 | 1253 | } |
7c116f2b WF |
1254 | if (hwpoison_filter(p)) { |
1255 | if (TestClearPageHWPoison(p)) | |
b37ff71c | 1256 | num_poisoned_pages_dec(); |
761ad8d7 NH |
1257 | unlock_page(p); |
1258 | put_hwpoison_page(p); | |
7c116f2b WF |
1259 | return 0; |
1260 | } | |
847ce401 | 1261 | |
761ad8d7 | 1262 | if (!PageTransTail(p) && !PageLRU(p)) |
0bc1f8b0 CY |
1263 | goto identify_page_state; |
1264 | ||
6edd6cc6 NH |
1265 | /* |
1266 | * It's very difficult to mess with pages currently under IO | |
1267 | * and in many cases impossible, so we just avoid it here. | |
1268 | */ | |
6a46079c AK |
1269 | wait_on_page_writeback(p); |
1270 | ||
1271 | /* | |
1272 | * Now take care of user space mappings. | |
e64a782f | 1273 | * Abort on fail: __delete_from_page_cache() assumes unmapped page. |
54b9dd14 NH |
1274 | * |
1275 | * When the raw error page is thp tail page, hpage points to the raw | |
1276 | * page after thp split. | |
6a46079c | 1277 | */ |
83b57531 | 1278 | if (!hwpoison_user_mappings(p, pfn, flags, &hpage)) { |
cc637b17 | 1279 | action_result(pfn, MF_MSG_UNMAP_FAILED, MF_IGNORED); |
1668bfd5 WF |
1280 | res = -EBUSY; |
1281 | goto out; | |
1282 | } | |
6a46079c AK |
1283 | |
1284 | /* | |
1285 | * Torn down by someone else? | |
1286 | */ | |
dc2a1cbf | 1287 | if (PageLRU(p) && !PageSwapCache(p) && p->mapping == NULL) { |
cc637b17 | 1288 | action_result(pfn, MF_MSG_TRUNCATED_LRU, MF_IGNORED); |
d95ea51e | 1289 | res = -EBUSY; |
6a46079c AK |
1290 | goto out; |
1291 | } | |
1292 | ||
0bc1f8b0 | 1293 | identify_page_state: |
0348d2eb | 1294 | res = identify_page_state(pfn, p, page_flags); |
6a46079c | 1295 | out: |
761ad8d7 | 1296 | unlock_page(p); |
6a46079c AK |
1297 | return res; |
1298 | } | |
cd42f4a3 | 1299 | EXPORT_SYMBOL_GPL(memory_failure); |
847ce401 | 1300 | |
ea8f5fb8 HY |
1301 | #define MEMORY_FAILURE_FIFO_ORDER 4 |
1302 | #define MEMORY_FAILURE_FIFO_SIZE (1 << MEMORY_FAILURE_FIFO_ORDER) | |
1303 | ||
1304 | struct memory_failure_entry { | |
1305 | unsigned long pfn; | |
ea8f5fb8 HY |
1306 | int flags; |
1307 | }; | |
1308 | ||
1309 | struct memory_failure_cpu { | |
1310 | DECLARE_KFIFO(fifo, struct memory_failure_entry, | |
1311 | MEMORY_FAILURE_FIFO_SIZE); | |
1312 | spinlock_t lock; | |
1313 | struct work_struct work; | |
1314 | }; | |
1315 | ||
1316 | static DEFINE_PER_CPU(struct memory_failure_cpu, memory_failure_cpu); | |
1317 | ||
1318 | /** | |
1319 | * memory_failure_queue - Schedule handling memory failure of a page. | |
1320 | * @pfn: Page Number of the corrupted page | |
ea8f5fb8 HY |
1321 | * @flags: Flags for memory failure handling |
1322 | * | |
1323 | * This function is called by the low level hardware error handler | |
1324 | * when it detects hardware memory corruption of a page. It schedules | |
1325 | * the recovering of error page, including dropping pages, killing | |
1326 | * processes etc. | |
1327 | * | |
1328 | * The function is primarily of use for corruptions that | |
1329 | * happen outside the current execution context (e.g. when | |
1330 | * detected by a background scrubber) | |
1331 | * | |
1332 | * Can run in IRQ context. | |
1333 | */ | |
83b57531 | 1334 | void memory_failure_queue(unsigned long pfn, int flags) |
ea8f5fb8 HY |
1335 | { |
1336 | struct memory_failure_cpu *mf_cpu; | |
1337 | unsigned long proc_flags; | |
1338 | struct memory_failure_entry entry = { | |
1339 | .pfn = pfn, | |
ea8f5fb8 HY |
1340 | .flags = flags, |
1341 | }; | |
1342 | ||
1343 | mf_cpu = &get_cpu_var(memory_failure_cpu); | |
1344 | spin_lock_irqsave(&mf_cpu->lock, proc_flags); | |
498d319b | 1345 | if (kfifo_put(&mf_cpu->fifo, entry)) |
ea8f5fb8 HY |
1346 | schedule_work_on(smp_processor_id(), &mf_cpu->work); |
1347 | else | |
8e33a52f | 1348 | pr_err("Memory failure: buffer overflow when queuing memory failure at %#lx\n", |
ea8f5fb8 HY |
1349 | pfn); |
1350 | spin_unlock_irqrestore(&mf_cpu->lock, proc_flags); | |
1351 | put_cpu_var(memory_failure_cpu); | |
1352 | } | |
1353 | EXPORT_SYMBOL_GPL(memory_failure_queue); | |
1354 | ||
1355 | static void memory_failure_work_func(struct work_struct *work) | |
1356 | { | |
1357 | struct memory_failure_cpu *mf_cpu; | |
1358 | struct memory_failure_entry entry = { 0, }; | |
1359 | unsigned long proc_flags; | |
1360 | int gotten; | |
1361 | ||
7c8e0181 | 1362 | mf_cpu = this_cpu_ptr(&memory_failure_cpu); |
ea8f5fb8 HY |
1363 | for (;;) { |
1364 | spin_lock_irqsave(&mf_cpu->lock, proc_flags); | |
1365 | gotten = kfifo_get(&mf_cpu->fifo, &entry); | |
1366 | spin_unlock_irqrestore(&mf_cpu->lock, proc_flags); | |
1367 | if (!gotten) | |
1368 | break; | |
cf870c70 NR |
1369 | if (entry.flags & MF_SOFT_OFFLINE) |
1370 | soft_offline_page(pfn_to_page(entry.pfn), entry.flags); | |
1371 | else | |
83b57531 | 1372 | memory_failure(entry.pfn, entry.flags); |
ea8f5fb8 HY |
1373 | } |
1374 | } | |
1375 | ||
1376 | static int __init memory_failure_init(void) | |
1377 | { | |
1378 | struct memory_failure_cpu *mf_cpu; | |
1379 | int cpu; | |
1380 | ||
1381 | for_each_possible_cpu(cpu) { | |
1382 | mf_cpu = &per_cpu(memory_failure_cpu, cpu); | |
1383 | spin_lock_init(&mf_cpu->lock); | |
1384 | INIT_KFIFO(mf_cpu->fifo); | |
1385 | INIT_WORK(&mf_cpu->work, memory_failure_work_func); | |
1386 | } | |
1387 | ||
1388 | return 0; | |
1389 | } | |
1390 | core_initcall(memory_failure_init); | |
1391 | ||
a5f65109 NH |
1392 | #define unpoison_pr_info(fmt, pfn, rs) \ |
1393 | ({ \ | |
1394 | if (__ratelimit(rs)) \ | |
1395 | pr_info(fmt, pfn); \ | |
1396 | }) | |
1397 | ||
847ce401 WF |
1398 | /** |
1399 | * unpoison_memory - Unpoison a previously poisoned page | |
1400 | * @pfn: Page number of the to be unpoisoned page | |
1401 | * | |
1402 | * Software-unpoison a page that has been poisoned by | |
1403 | * memory_failure() earlier. | |
1404 | * | |
1405 | * This is only done on the software-level, so it only works | |
1406 | * for linux injected failures, not real hardware failures | |
1407 | * | |
1408 | * Returns 0 for success, otherwise -errno. | |
1409 | */ | |
1410 | int unpoison_memory(unsigned long pfn) | |
1411 | { | |
1412 | struct page *page; | |
1413 | struct page *p; | |
1414 | int freeit = 0; | |
a5f65109 NH |
1415 | static DEFINE_RATELIMIT_STATE(unpoison_rs, DEFAULT_RATELIMIT_INTERVAL, |
1416 | DEFAULT_RATELIMIT_BURST); | |
847ce401 WF |
1417 | |
1418 | if (!pfn_valid(pfn)) | |
1419 | return -ENXIO; | |
1420 | ||
1421 | p = pfn_to_page(pfn); | |
1422 | page = compound_head(p); | |
1423 | ||
1424 | if (!PageHWPoison(p)) { | |
495367c0 | 1425 | unpoison_pr_info("Unpoison: Page was already unpoisoned %#lx\n", |
a5f65109 | 1426 | pfn, &unpoison_rs); |
847ce401 WF |
1427 | return 0; |
1428 | } | |
1429 | ||
230ac719 | 1430 | if (page_count(page) > 1) { |
495367c0 | 1431 | unpoison_pr_info("Unpoison: Someone grabs the hwpoison page %#lx\n", |
a5f65109 | 1432 | pfn, &unpoison_rs); |
230ac719 NH |
1433 | return 0; |
1434 | } | |
1435 | ||
1436 | if (page_mapped(page)) { | |
495367c0 | 1437 | unpoison_pr_info("Unpoison: Someone maps the hwpoison page %#lx\n", |
a5f65109 | 1438 | pfn, &unpoison_rs); |
230ac719 NH |
1439 | return 0; |
1440 | } | |
1441 | ||
1442 | if (page_mapping(page)) { | |
495367c0 | 1443 | unpoison_pr_info("Unpoison: the hwpoison page has non-NULL mapping %#lx\n", |
a5f65109 | 1444 | pfn, &unpoison_rs); |
230ac719 NH |
1445 | return 0; |
1446 | } | |
1447 | ||
0cea3fdc WL |
1448 | /* |
1449 | * unpoison_memory() can encounter thp only when the thp is being | |
1450 | * worked by memory_failure() and the page lock is not held yet. | |
1451 | * In such case, we yield to memory_failure() and make unpoison fail. | |
1452 | */ | |
e76d30e2 | 1453 | if (!PageHuge(page) && PageTransHuge(page)) { |
495367c0 | 1454 | unpoison_pr_info("Unpoison: Memory failure is now running on %#lx\n", |
a5f65109 | 1455 | pfn, &unpoison_rs); |
ead07f6a | 1456 | return 0; |
0cea3fdc WL |
1457 | } |
1458 | ||
ead07f6a | 1459 | if (!get_hwpoison_page(p)) { |
847ce401 | 1460 | if (TestClearPageHWPoison(p)) |
8e30456b | 1461 | num_poisoned_pages_dec(); |
495367c0 | 1462 | unpoison_pr_info("Unpoison: Software-unpoisoned free page %#lx\n", |
a5f65109 | 1463 | pfn, &unpoison_rs); |
847ce401 WF |
1464 | return 0; |
1465 | } | |
1466 | ||
7eaceacc | 1467 | lock_page(page); |
847ce401 WF |
1468 | /* |
1469 | * This test is racy because PG_hwpoison is set outside of page lock. | |
1470 | * That's acceptable because that won't trigger kernel panic. Instead, | |
1471 | * the PG_hwpoison page will be caught and isolated on the entrance to | |
1472 | * the free buddy page pool. | |
1473 | */ | |
c9fbdd5f | 1474 | if (TestClearPageHWPoison(page)) { |
495367c0 | 1475 | unpoison_pr_info("Unpoison: Software-unpoisoned page %#lx\n", |
a5f65109 | 1476 | pfn, &unpoison_rs); |
b37ff71c | 1477 | num_poisoned_pages_dec(); |
847ce401 WF |
1478 | freeit = 1; |
1479 | } | |
1480 | unlock_page(page); | |
1481 | ||
665d9da7 | 1482 | put_hwpoison_page(page); |
3ba5eebc | 1483 | if (freeit && !(pfn == my_zero_pfn(0) && page_count(p) == 1)) |
665d9da7 | 1484 | put_hwpoison_page(page); |
847ce401 WF |
1485 | |
1486 | return 0; | |
1487 | } | |
1488 | EXPORT_SYMBOL(unpoison_memory); | |
facb6011 AK |
1489 | |
1490 | static struct page *new_page(struct page *p, unsigned long private, int **x) | |
1491 | { | |
12686d15 | 1492 | int nid = page_to_nid(p); |
94310cbc | 1493 | |
ef77ba5c | 1494 | return new_page_nodemask(p, nid, &node_states[N_MEMORY]); |
facb6011 AK |
1495 | } |
1496 | ||
1497 | /* | |
1498 | * Safely get reference count of an arbitrary page. | |
1499 | * Returns 0 for a free page, -EIO for a zero refcount page | |
1500 | * that is not free, and 1 for any other page type. | |
1501 | * For 1 the page is returned with increased page count, otherwise not. | |
1502 | */ | |
af8fae7c | 1503 | static int __get_any_page(struct page *p, unsigned long pfn, int flags) |
facb6011 AK |
1504 | { |
1505 | int ret; | |
1506 | ||
1507 | if (flags & MF_COUNT_INCREASED) | |
1508 | return 1; | |
1509 | ||
d950b958 NH |
1510 | /* |
1511 | * When the target page is a free hugepage, just remove it | |
1512 | * from free hugepage list. | |
1513 | */ | |
ead07f6a | 1514 | if (!get_hwpoison_page(p)) { |
d950b958 | 1515 | if (PageHuge(p)) { |
71dd0b8a | 1516 | pr_info("%s: %#lx free huge page\n", __func__, pfn); |
af8fae7c | 1517 | ret = 0; |
d950b958 | 1518 | } else if (is_free_buddy_page(p)) { |
71dd0b8a | 1519 | pr_info("%s: %#lx free buddy page\n", __func__, pfn); |
facb6011 AK |
1520 | ret = 0; |
1521 | } else { | |
71dd0b8a BP |
1522 | pr_info("%s: %#lx: unknown zero refcount page type %lx\n", |
1523 | __func__, pfn, p->flags); | |
facb6011 AK |
1524 | ret = -EIO; |
1525 | } | |
1526 | } else { | |
1527 | /* Not a free page */ | |
1528 | ret = 1; | |
1529 | } | |
facb6011 AK |
1530 | return ret; |
1531 | } | |
1532 | ||
af8fae7c NH |
1533 | static int get_any_page(struct page *page, unsigned long pfn, int flags) |
1534 | { | |
1535 | int ret = __get_any_page(page, pfn, flags); | |
1536 | ||
85fbe5d1 YX |
1537 | if (ret == 1 && !PageHuge(page) && |
1538 | !PageLRU(page) && !__PageMovable(page)) { | |
af8fae7c NH |
1539 | /* |
1540 | * Try to free it. | |
1541 | */ | |
665d9da7 | 1542 | put_hwpoison_page(page); |
af8fae7c NH |
1543 | shake_page(page, 1); |
1544 | ||
1545 | /* | |
1546 | * Did it turn free? | |
1547 | */ | |
1548 | ret = __get_any_page(page, pfn, 0); | |
d96b339f | 1549 | if (ret == 1 && !PageLRU(page)) { |
4f32be67 | 1550 | /* Drop page reference which is from __get_any_page() */ |
665d9da7 | 1551 | put_hwpoison_page(page); |
82a2481e AK |
1552 | pr_info("soft_offline: %#lx: unknown non LRU page type %lx (%pGp)\n", |
1553 | pfn, page->flags, &page->flags); | |
af8fae7c NH |
1554 | return -EIO; |
1555 | } | |
1556 | } | |
1557 | return ret; | |
1558 | } | |
1559 | ||
d950b958 NH |
1560 | static int soft_offline_huge_page(struct page *page, int flags) |
1561 | { | |
1562 | int ret; | |
1563 | unsigned long pfn = page_to_pfn(page); | |
1564 | struct page *hpage = compound_head(page); | |
b8ec1cee | 1565 | LIST_HEAD(pagelist); |
d950b958 | 1566 | |
af8fae7c NH |
1567 | /* |
1568 | * This double-check of PageHWPoison is to avoid the race with | |
1569 | * memory_failure(). See also comment in __soft_offline_page(). | |
1570 | */ | |
1571 | lock_page(hpage); | |
0ebff32c | 1572 | if (PageHWPoison(hpage)) { |
af8fae7c | 1573 | unlock_page(hpage); |
665d9da7 | 1574 | put_hwpoison_page(hpage); |
0ebff32c | 1575 | pr_info("soft offline: %#lx hugepage already poisoned\n", pfn); |
af8fae7c | 1576 | return -EBUSY; |
0ebff32c | 1577 | } |
af8fae7c | 1578 | unlock_page(hpage); |
d950b958 | 1579 | |
bcc54222 | 1580 | ret = isolate_huge_page(hpage, &pagelist); |
03613808 WL |
1581 | /* |
1582 | * get_any_page() and isolate_huge_page() takes a refcount each, | |
1583 | * so need to drop one here. | |
1584 | */ | |
665d9da7 | 1585 | put_hwpoison_page(hpage); |
03613808 | 1586 | if (!ret) { |
bcc54222 NH |
1587 | pr_info("soft offline: %#lx hugepage failed to isolate\n", pfn); |
1588 | return -EBUSY; | |
1589 | } | |
1590 | ||
68711a74 | 1591 | ret = migrate_pages(&pagelist, new_page, NULL, MPOL_MF_MOVE_ALL, |
b8ec1cee | 1592 | MIGRATE_SYNC, MR_MEMORY_FAILURE); |
d950b958 | 1593 | if (ret) { |
b6b18aa8 | 1594 | pr_info("soft offline: %#lx: hugepage migration failed %d, type %lx (%pGp)\n", |
82a2481e | 1595 | pfn, ret, page->flags, &page->flags); |
30809f55 PA |
1596 | if (!list_empty(&pagelist)) |
1597 | putback_movable_pages(&pagelist); | |
b8ec1cee NH |
1598 | if (ret > 0) |
1599 | ret = -EIO; | |
af8fae7c | 1600 | } else { |
b37ff71c | 1601 | if (PageHuge(page)) |
c3114a84 | 1602 | dissolve_free_huge_page(page); |
d950b958 | 1603 | } |
d950b958 NH |
1604 | return ret; |
1605 | } | |
1606 | ||
af8fae7c NH |
1607 | static int __soft_offline_page(struct page *page, int flags) |
1608 | { | |
1609 | int ret; | |
1610 | unsigned long pfn = page_to_pfn(page); | |
facb6011 | 1611 | |
facb6011 | 1612 | /* |
af8fae7c NH |
1613 | * Check PageHWPoison again inside page lock because PageHWPoison |
1614 | * is set by memory_failure() outside page lock. Note that | |
1615 | * memory_failure() also double-checks PageHWPoison inside page lock, | |
1616 | * so there's no race between soft_offline_page() and memory_failure(). | |
facb6011 | 1617 | */ |
0ebff32c XQ |
1618 | lock_page(page); |
1619 | wait_on_page_writeback(page); | |
af8fae7c NH |
1620 | if (PageHWPoison(page)) { |
1621 | unlock_page(page); | |
665d9da7 | 1622 | put_hwpoison_page(page); |
af8fae7c NH |
1623 | pr_info("soft offline: %#lx page already poisoned\n", pfn); |
1624 | return -EBUSY; | |
1625 | } | |
facb6011 AK |
1626 | /* |
1627 | * Try to invalidate first. This should work for | |
1628 | * non dirty unmapped page cache pages. | |
1629 | */ | |
1630 | ret = invalidate_inode_page(page); | |
1631 | unlock_page(page); | |
facb6011 | 1632 | /* |
facb6011 AK |
1633 | * RED-PEN would be better to keep it isolated here, but we |
1634 | * would need to fix isolation locking first. | |
1635 | */ | |
facb6011 | 1636 | if (ret == 1) { |
665d9da7 | 1637 | put_hwpoison_page(page); |
fb46e735 | 1638 | pr_info("soft_offline: %#lx: invalidated\n", pfn); |
af8fae7c | 1639 | SetPageHWPoison(page); |
8e30456b | 1640 | num_poisoned_pages_inc(); |
af8fae7c | 1641 | return 0; |
facb6011 AK |
1642 | } |
1643 | ||
1644 | /* | |
1645 | * Simple invalidation didn't work. | |
1646 | * Try to migrate to a new page instead. migrate.c | |
1647 | * handles a large number of cases for us. | |
1648 | */ | |
85fbe5d1 YX |
1649 | if (PageLRU(page)) |
1650 | ret = isolate_lru_page(page); | |
1651 | else | |
1652 | ret = isolate_movable_page(page, ISOLATE_UNEVICTABLE); | |
bd486285 KK |
1653 | /* |
1654 | * Drop page reference which is came from get_any_page() | |
1655 | * successful isolate_lru_page() already took another one. | |
1656 | */ | |
665d9da7 | 1657 | put_hwpoison_page(page); |
facb6011 AK |
1658 | if (!ret) { |
1659 | LIST_HEAD(pagelist); | |
85fbe5d1 YX |
1660 | /* |
1661 | * After isolated lru page, the PageLRU will be cleared, | |
1662 | * so use !__PageMovable instead for LRU page's mapping | |
1663 | * cannot have PAGE_MAPPING_MOVABLE. | |
1664 | */ | |
1665 | if (!__PageMovable(page)) | |
1666 | inc_node_page_state(page, NR_ISOLATED_ANON + | |
1667 | page_is_file_cache(page)); | |
facb6011 | 1668 | list_add(&page->lru, &pagelist); |
68711a74 | 1669 | ret = migrate_pages(&pagelist, new_page, NULL, MPOL_MF_MOVE_ALL, |
9c620e2b | 1670 | MIGRATE_SYNC, MR_MEMORY_FAILURE); |
facb6011 | 1671 | if (ret) { |
85fbe5d1 YX |
1672 | if (!list_empty(&pagelist)) |
1673 | putback_movable_pages(&pagelist); | |
59c82b70 | 1674 | |
82a2481e AK |
1675 | pr_info("soft offline: %#lx: migration failed %d, type %lx (%pGp)\n", |
1676 | pfn, ret, page->flags, &page->flags); | |
facb6011 AK |
1677 | if (ret > 0) |
1678 | ret = -EIO; | |
1679 | } | |
1680 | } else { | |
82a2481e AK |
1681 | pr_info("soft offline: %#lx: isolation failed: %d, page count %d, type %lx (%pGp)\n", |
1682 | pfn, ret, page_count(page), page->flags, &page->flags); | |
facb6011 | 1683 | } |
facb6011 AK |
1684 | return ret; |
1685 | } | |
86e05773 | 1686 | |
acc14dc4 NH |
1687 | static int soft_offline_in_use_page(struct page *page, int flags) |
1688 | { | |
1689 | int ret; | |
1690 | struct page *hpage = compound_head(page); | |
1691 | ||
1692 | if (!PageHuge(page) && PageTransHuge(hpage)) { | |
1693 | lock_page(hpage); | |
98fd1ef4 NH |
1694 | if (!PageAnon(hpage) || unlikely(split_huge_page(hpage))) { |
1695 | unlock_page(hpage); | |
1696 | if (!PageAnon(hpage)) | |
1697 | pr_info("soft offline: %#lx: non anonymous thp\n", page_to_pfn(page)); | |
1698 | else | |
1699 | pr_info("soft offline: %#lx: thp split failed\n", page_to_pfn(page)); | |
1700 | put_hwpoison_page(hpage); | |
acc14dc4 NH |
1701 | return -EBUSY; |
1702 | } | |
98fd1ef4 | 1703 | unlock_page(hpage); |
acc14dc4 NH |
1704 | get_hwpoison_page(page); |
1705 | put_hwpoison_page(hpage); | |
1706 | } | |
1707 | ||
1708 | if (PageHuge(page)) | |
1709 | ret = soft_offline_huge_page(page, flags); | |
1710 | else | |
1711 | ret = __soft_offline_page(page, flags); | |
1712 | ||
1713 | return ret; | |
1714 | } | |
1715 | ||
1716 | static void soft_offline_free_page(struct page *page) | |
1717 | { | |
b37ff71c | 1718 | struct page *head = compound_head(page); |
acc14dc4 | 1719 | |
b37ff71c NH |
1720 | if (!TestSetPageHWPoison(head)) { |
1721 | num_poisoned_pages_inc(); | |
1722 | if (PageHuge(head)) | |
d4a3a60b | 1723 | dissolve_free_huge_page(page); |
acc14dc4 NH |
1724 | } |
1725 | } | |
1726 | ||
86e05773 WL |
1727 | /** |
1728 | * soft_offline_page - Soft offline a page. | |
1729 | * @page: page to offline | |
1730 | * @flags: flags. Same as memory_failure(). | |
1731 | * | |
1732 | * Returns 0 on success, otherwise negated errno. | |
1733 | * | |
1734 | * Soft offline a page, by migration or invalidation, | |
1735 | * without killing anything. This is for the case when | |
1736 | * a page is not corrupted yet (so it's still valid to access), | |
1737 | * but has had a number of corrected errors and is better taken | |
1738 | * out. | |
1739 | * | |
1740 | * The actual policy on when to do that is maintained by | |
1741 | * user space. | |
1742 | * | |
1743 | * This should never impact any application or cause data loss, | |
1744 | * however it might take some time. | |
1745 | * | |
1746 | * This is not a 100% solution for all memory, but tries to be | |
1747 | * ``good enough'' for the majority of memory. | |
1748 | */ | |
1749 | int soft_offline_page(struct page *page, int flags) | |
1750 | { | |
1751 | int ret; | |
1752 | unsigned long pfn = page_to_pfn(page); | |
86e05773 WL |
1753 | |
1754 | if (PageHWPoison(page)) { | |
1755 | pr_info("soft offline: %#lx page already poisoned\n", pfn); | |
1e0e635b | 1756 | if (flags & MF_COUNT_INCREASED) |
665d9da7 | 1757 | put_hwpoison_page(page); |
86e05773 WL |
1758 | return -EBUSY; |
1759 | } | |
86e05773 | 1760 | |
bfc8c901 | 1761 | get_online_mems(); |
86e05773 | 1762 | ret = get_any_page(page, pfn, flags); |
bfc8c901 | 1763 | put_online_mems(); |
4e41a30c | 1764 | |
acc14dc4 NH |
1765 | if (ret > 0) |
1766 | ret = soft_offline_in_use_page(page, flags); | |
1767 | else if (ret == 0) | |
1768 | soft_offline_free_page(page); | |
4e41a30c | 1769 | |
86e05773 WL |
1770 | return ret; |
1771 | } |