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1439f94c | 1 | // SPDX-License-Identifier: GPL-2.0-only |
6a46079c AK |
2 | /* |
3 | * Copyright (C) 2008, 2009 Intel Corporation | |
4 | * Authors: Andi Kleen, Fengguang Wu | |
5 | * | |
6a46079c | 6 | * High level machine check handler. Handles pages reported by the |
1c80b990 | 7 | * hardware as being corrupted usually due to a multi-bit ECC memory or cache |
6a46079c | 8 | * failure. |
1c80b990 AK |
9 | * |
10 | * In addition there is a "soft offline" entry point that allows stop using | |
11 | * not-yet-corrupted-by-suspicious pages without killing anything. | |
6a46079c AK |
12 | * |
13 | * Handles page cache pages in various states. The tricky part | |
1c80b990 AK |
14 | * here is that we can access any page asynchronously in respect to |
15 | * other VM users, because memory failures could happen anytime and | |
16 | * anywhere. This could violate some of their assumptions. This is why | |
17 | * this code has to be extremely careful. Generally it tries to use | |
18 | * normal locking rules, as in get the standard locks, even if that means | |
19 | * the error handling takes potentially a long time. | |
e0de78df AK |
20 | * |
21 | * It can be very tempting to add handling for obscure cases here. | |
22 | * In general any code for handling new cases should only be added iff: | |
23 | * - You know how to test it. | |
24 | * - You have a test that can be added to mce-test | |
25 | * https://git.kernel.org/cgit/utils/cpu/mce/mce-test.git/ | |
26 | * - The case actually shows up as a frequent (top 10) page state in | |
27 | * tools/vm/page-types when running a real workload. | |
1c80b990 AK |
28 | * |
29 | * There are several operations here with exponential complexity because | |
30 | * of unsuitable VM data structures. For example the operation to map back | |
31 | * from RMAP chains to processes has to walk the complete process list and | |
32 | * has non linear complexity with the number. But since memory corruptions | |
33 | * are rare we hope to get away with this. This avoids impacting the core | |
34 | * VM. | |
6a46079c | 35 | */ |
6a46079c AK |
36 | #include <linux/kernel.h> |
37 | #include <linux/mm.h> | |
38 | #include <linux/page-flags.h> | |
478c5ffc | 39 | #include <linux/kernel-page-flags.h> |
3f07c014 | 40 | #include <linux/sched/signal.h> |
29930025 | 41 | #include <linux/sched/task.h> |
01e00f88 | 42 | #include <linux/ksm.h> |
6a46079c | 43 | #include <linux/rmap.h> |
b9e15baf | 44 | #include <linux/export.h> |
6a46079c AK |
45 | #include <linux/pagemap.h> |
46 | #include <linux/swap.h> | |
47 | #include <linux/backing-dev.h> | |
facb6011 | 48 | #include <linux/migrate.h> |
facb6011 | 49 | #include <linux/suspend.h> |
5a0e3ad6 | 50 | #include <linux/slab.h> |
bf998156 | 51 | #include <linux/swapops.h> |
7af446a8 | 52 | #include <linux/hugetlb.h> |
20d6c96b | 53 | #include <linux/memory_hotplug.h> |
5db8a73a | 54 | #include <linux/mm_inline.h> |
6100e34b | 55 | #include <linux/memremap.h> |
ea8f5fb8 | 56 | #include <linux/kfifo.h> |
a5f65109 | 57 | #include <linux/ratelimit.h> |
d4ae9916 | 58 | #include <linux/page-isolation.h> |
6a46079c | 59 | #include "internal.h" |
97f0b134 | 60 | #include "ras/ras_event.h" |
6a46079c AK |
61 | |
62 | int sysctl_memory_failure_early_kill __read_mostly = 0; | |
63 | ||
64 | int sysctl_memory_failure_recovery __read_mostly = 1; | |
65 | ||
293c07e3 | 66 | atomic_long_t num_poisoned_pages __read_mostly = ATOMIC_LONG_INIT(0); |
6a46079c | 67 | |
27df5068 AK |
68 | #if defined(CONFIG_HWPOISON_INJECT) || defined(CONFIG_HWPOISON_INJECT_MODULE) |
69 | ||
1bfe5feb | 70 | u32 hwpoison_filter_enable = 0; |
7c116f2b WF |
71 | u32 hwpoison_filter_dev_major = ~0U; |
72 | u32 hwpoison_filter_dev_minor = ~0U; | |
478c5ffc WF |
73 | u64 hwpoison_filter_flags_mask; |
74 | u64 hwpoison_filter_flags_value; | |
1bfe5feb | 75 | EXPORT_SYMBOL_GPL(hwpoison_filter_enable); |
7c116f2b WF |
76 | EXPORT_SYMBOL_GPL(hwpoison_filter_dev_major); |
77 | EXPORT_SYMBOL_GPL(hwpoison_filter_dev_minor); | |
478c5ffc WF |
78 | EXPORT_SYMBOL_GPL(hwpoison_filter_flags_mask); |
79 | EXPORT_SYMBOL_GPL(hwpoison_filter_flags_value); | |
7c116f2b WF |
80 | |
81 | static int hwpoison_filter_dev(struct page *p) | |
82 | { | |
83 | struct address_space *mapping; | |
84 | dev_t dev; | |
85 | ||
86 | if (hwpoison_filter_dev_major == ~0U && | |
87 | hwpoison_filter_dev_minor == ~0U) | |
88 | return 0; | |
89 | ||
90 | /* | |
1c80b990 | 91 | * page_mapping() does not accept slab pages. |
7c116f2b WF |
92 | */ |
93 | if (PageSlab(p)) | |
94 | return -EINVAL; | |
95 | ||
96 | mapping = page_mapping(p); | |
97 | if (mapping == NULL || mapping->host == NULL) | |
98 | return -EINVAL; | |
99 | ||
100 | dev = mapping->host->i_sb->s_dev; | |
101 | if (hwpoison_filter_dev_major != ~0U && | |
102 | hwpoison_filter_dev_major != MAJOR(dev)) | |
103 | return -EINVAL; | |
104 | if (hwpoison_filter_dev_minor != ~0U && | |
105 | hwpoison_filter_dev_minor != MINOR(dev)) | |
106 | return -EINVAL; | |
107 | ||
108 | return 0; | |
109 | } | |
110 | ||
478c5ffc WF |
111 | static int hwpoison_filter_flags(struct page *p) |
112 | { | |
113 | if (!hwpoison_filter_flags_mask) | |
114 | return 0; | |
115 | ||
116 | if ((stable_page_flags(p) & hwpoison_filter_flags_mask) == | |
117 | hwpoison_filter_flags_value) | |
118 | return 0; | |
119 | else | |
120 | return -EINVAL; | |
121 | } | |
122 | ||
4fd466eb AK |
123 | /* |
124 | * This allows stress tests to limit test scope to a collection of tasks | |
125 | * by putting them under some memcg. This prevents killing unrelated/important | |
126 | * processes such as /sbin/init. Note that the target task may share clean | |
127 | * pages with init (eg. libc text), which is harmless. If the target task | |
128 | * share _dirty_ pages with another task B, the test scheme must make sure B | |
129 | * is also included in the memcg. At last, due to race conditions this filter | |
130 | * can only guarantee that the page either belongs to the memcg tasks, or is | |
131 | * a freed page. | |
132 | */ | |
94a59fb3 | 133 | #ifdef CONFIG_MEMCG |
4fd466eb AK |
134 | u64 hwpoison_filter_memcg; |
135 | EXPORT_SYMBOL_GPL(hwpoison_filter_memcg); | |
136 | static int hwpoison_filter_task(struct page *p) | |
137 | { | |
4fd466eb AK |
138 | if (!hwpoison_filter_memcg) |
139 | return 0; | |
140 | ||
94a59fb3 | 141 | if (page_cgroup_ino(p) != hwpoison_filter_memcg) |
4fd466eb AK |
142 | return -EINVAL; |
143 | ||
144 | return 0; | |
145 | } | |
146 | #else | |
147 | static int hwpoison_filter_task(struct page *p) { return 0; } | |
148 | #endif | |
149 | ||
7c116f2b WF |
150 | int hwpoison_filter(struct page *p) |
151 | { | |
1bfe5feb HL |
152 | if (!hwpoison_filter_enable) |
153 | return 0; | |
154 | ||
7c116f2b WF |
155 | if (hwpoison_filter_dev(p)) |
156 | return -EINVAL; | |
157 | ||
478c5ffc WF |
158 | if (hwpoison_filter_flags(p)) |
159 | return -EINVAL; | |
160 | ||
4fd466eb AK |
161 | if (hwpoison_filter_task(p)) |
162 | return -EINVAL; | |
163 | ||
7c116f2b WF |
164 | return 0; |
165 | } | |
27df5068 AK |
166 | #else |
167 | int hwpoison_filter(struct page *p) | |
168 | { | |
169 | return 0; | |
170 | } | |
171 | #endif | |
172 | ||
7c116f2b WF |
173 | EXPORT_SYMBOL_GPL(hwpoison_filter); |
174 | ||
ae1139ec DW |
175 | /* |
176 | * Kill all processes that have a poisoned page mapped and then isolate | |
177 | * the page. | |
178 | * | |
179 | * General strategy: | |
180 | * Find all processes having the page mapped and kill them. | |
181 | * But we keep a page reference around so that the page is not | |
182 | * actually freed yet. | |
183 | * Then stash the page away | |
184 | * | |
185 | * There's no convenient way to get back to mapped processes | |
186 | * from the VMAs. So do a brute-force search over all | |
187 | * running processes. | |
188 | * | |
189 | * Remember that machine checks are not common (or rather | |
190 | * if they are common you have other problems), so this shouldn't | |
191 | * be a performance issue. | |
192 | * | |
193 | * Also there are some races possible while we get from the | |
194 | * error detection to actually handle it. | |
195 | */ | |
196 | ||
197 | struct to_kill { | |
198 | struct list_head nd; | |
199 | struct task_struct *tsk; | |
200 | unsigned long addr; | |
201 | short size_shift; | |
202 | char addr_valid; | |
203 | }; | |
204 | ||
6a46079c | 205 | /* |
7329bbeb TL |
206 | * Send all the processes who have the page mapped a signal. |
207 | * ``action optional'' if they are not immediately affected by the error | |
208 | * ``action required'' if error happened in current execution context | |
6a46079c | 209 | */ |
ae1139ec | 210 | static int kill_proc(struct to_kill *tk, unsigned long pfn, int flags) |
6a46079c | 211 | { |
ae1139ec DW |
212 | struct task_struct *t = tk->tsk; |
213 | short addr_lsb = tk->size_shift; | |
6a46079c AK |
214 | int ret; |
215 | ||
135e5351 | 216 | pr_err("Memory failure: %#lx: Sending SIGBUS to %s:%d due to hardware memory corruption\n", |
495367c0 | 217 | pfn, t->comm, t->pid); |
7329bbeb | 218 | |
a70ffcac | 219 | if ((flags & MF_ACTION_REQUIRED) && t->mm == current->mm) { |
ae1139ec | 220 | ret = force_sig_mceerr(BUS_MCEERR_AR, (void __user *)tk->addr, |
f8eac901 | 221 | addr_lsb); |
7329bbeb TL |
222 | } else { |
223 | /* | |
224 | * Don't use force here, it's convenient if the signal | |
225 | * can be temporarily blocked. | |
226 | * This could cause a loop when the user sets SIGBUS | |
227 | * to SIG_IGN, but hopefully no one will do that? | |
228 | */ | |
ae1139ec | 229 | ret = send_sig_mceerr(BUS_MCEERR_AO, (void __user *)tk->addr, |
c0f45555 | 230 | addr_lsb, t); /* synchronous? */ |
7329bbeb | 231 | } |
6a46079c | 232 | if (ret < 0) |
495367c0 | 233 | pr_info("Memory failure: Error sending signal to %s:%d: %d\n", |
1170532b | 234 | t->comm, t->pid, ret); |
6a46079c AK |
235 | return ret; |
236 | } | |
237 | ||
588f9ce6 AK |
238 | /* |
239 | * When a unknown page type is encountered drain as many buffers as possible | |
240 | * in the hope to turn the page into a LRU or free page, which we can handle. | |
241 | */ | |
facb6011 | 242 | void shake_page(struct page *p, int access) |
588f9ce6 | 243 | { |
8bcb74de NH |
244 | if (PageHuge(p)) |
245 | return; | |
246 | ||
588f9ce6 AK |
247 | if (!PageSlab(p)) { |
248 | lru_add_drain_all(); | |
249 | if (PageLRU(p)) | |
250 | return; | |
c0554329 | 251 | drain_all_pages(page_zone(p)); |
588f9ce6 AK |
252 | if (PageLRU(p) || is_free_buddy_page(p)) |
253 | return; | |
254 | } | |
facb6011 | 255 | |
588f9ce6 | 256 | /* |
6b4f7799 JW |
257 | * Only call shrink_node_slabs here (which would also shrink |
258 | * other caches) if access is not potentially fatal. | |
588f9ce6 | 259 | */ |
cb731d6c VD |
260 | if (access) |
261 | drop_slab_node(page_to_nid(p)); | |
588f9ce6 AK |
262 | } |
263 | EXPORT_SYMBOL_GPL(shake_page); | |
264 | ||
6100e34b DW |
265 | static unsigned long dev_pagemap_mapping_shift(struct page *page, |
266 | struct vm_area_struct *vma) | |
267 | { | |
268 | unsigned long address = vma_address(page, vma); | |
269 | pgd_t *pgd; | |
270 | p4d_t *p4d; | |
271 | pud_t *pud; | |
272 | pmd_t *pmd; | |
273 | pte_t *pte; | |
274 | ||
275 | pgd = pgd_offset(vma->vm_mm, address); | |
276 | if (!pgd_present(*pgd)) | |
277 | return 0; | |
278 | p4d = p4d_offset(pgd, address); | |
279 | if (!p4d_present(*p4d)) | |
280 | return 0; | |
281 | pud = pud_offset(p4d, address); | |
282 | if (!pud_present(*pud)) | |
283 | return 0; | |
284 | if (pud_devmap(*pud)) | |
285 | return PUD_SHIFT; | |
286 | pmd = pmd_offset(pud, address); | |
287 | if (!pmd_present(*pmd)) | |
288 | return 0; | |
289 | if (pmd_devmap(*pmd)) | |
290 | return PMD_SHIFT; | |
291 | pte = pte_offset_map(pmd, address); | |
292 | if (!pte_present(*pte)) | |
293 | return 0; | |
294 | if (pte_devmap(*pte)) | |
295 | return PAGE_SHIFT; | |
296 | return 0; | |
297 | } | |
6a46079c AK |
298 | |
299 | /* | |
300 | * Failure handling: if we can't find or can't kill a process there's | |
301 | * not much we can do. We just print a message and ignore otherwise. | |
302 | */ | |
303 | ||
304 | /* | |
305 | * Schedule a process for later kill. | |
306 | * Uses GFP_ATOMIC allocations to avoid potential recursions in the VM. | |
307 | * TBD would GFP_NOIO be enough? | |
308 | */ | |
309 | static void add_to_kill(struct task_struct *tsk, struct page *p, | |
310 | struct vm_area_struct *vma, | |
311 | struct list_head *to_kill, | |
312 | struct to_kill **tkc) | |
313 | { | |
314 | struct to_kill *tk; | |
315 | ||
316 | if (*tkc) { | |
317 | tk = *tkc; | |
318 | *tkc = NULL; | |
319 | } else { | |
320 | tk = kmalloc(sizeof(struct to_kill), GFP_ATOMIC); | |
321 | if (!tk) { | |
495367c0 | 322 | pr_err("Memory failure: Out of memory while machine check handling\n"); |
6a46079c AK |
323 | return; |
324 | } | |
325 | } | |
326 | tk->addr = page_address_in_vma(p, vma); | |
327 | tk->addr_valid = 1; | |
6100e34b DW |
328 | if (is_zone_device_page(p)) |
329 | tk->size_shift = dev_pagemap_mapping_shift(p, vma); | |
330 | else | |
331 | tk->size_shift = compound_order(compound_head(p)) + PAGE_SHIFT; | |
6a46079c AK |
332 | |
333 | /* | |
334 | * In theory we don't have to kill when the page was | |
335 | * munmaped. But it could be also a mremap. Since that's | |
336 | * likely very rare kill anyways just out of paranoia, but use | |
337 | * a SIGKILL because the error is not contained anymore. | |
338 | */ | |
6100e34b | 339 | if (tk->addr == -EFAULT || tk->size_shift == 0) { |
495367c0 | 340 | pr_info("Memory failure: Unable to find user space address %lx in %s\n", |
6a46079c AK |
341 | page_to_pfn(p), tsk->comm); |
342 | tk->addr_valid = 0; | |
343 | } | |
344 | get_task_struct(tsk); | |
345 | tk->tsk = tsk; | |
346 | list_add_tail(&tk->nd, to_kill); | |
347 | } | |
348 | ||
349 | /* | |
350 | * Kill the processes that have been collected earlier. | |
351 | * | |
352 | * Only do anything when DOIT is set, otherwise just free the list | |
353 | * (this is used for clean pages which do not need killing) | |
354 | * Also when FAIL is set do a force kill because something went | |
355 | * wrong earlier. | |
356 | */ | |
ae1139ec DW |
357 | static void kill_procs(struct list_head *to_kill, int forcekill, bool fail, |
358 | unsigned long pfn, int flags) | |
6a46079c AK |
359 | { |
360 | struct to_kill *tk, *next; | |
361 | ||
362 | list_for_each_entry_safe (tk, next, to_kill, nd) { | |
6751ed65 | 363 | if (forcekill) { |
6a46079c | 364 | /* |
af901ca1 | 365 | * In case something went wrong with munmapping |
6a46079c AK |
366 | * make sure the process doesn't catch the |
367 | * signal and then access the memory. Just kill it. | |
6a46079c AK |
368 | */ |
369 | if (fail || tk->addr_valid == 0) { | |
495367c0 | 370 | pr_err("Memory failure: %#lx: forcibly killing %s:%d because of failure to unmap corrupted page\n", |
1170532b | 371 | pfn, tk->tsk->comm, tk->tsk->pid); |
6376360e NH |
372 | do_send_sig_info(SIGKILL, SEND_SIG_PRIV, |
373 | tk->tsk, PIDTYPE_PID); | |
6a46079c AK |
374 | } |
375 | ||
376 | /* | |
377 | * In theory the process could have mapped | |
378 | * something else on the address in-between. We could | |
379 | * check for that, but we need to tell the | |
380 | * process anyways. | |
381 | */ | |
ae1139ec | 382 | else if (kill_proc(tk, pfn, flags) < 0) |
495367c0 | 383 | pr_err("Memory failure: %#lx: Cannot send advisory machine check signal to %s:%d\n", |
1170532b | 384 | pfn, tk->tsk->comm, tk->tsk->pid); |
6a46079c AK |
385 | } |
386 | put_task_struct(tk->tsk); | |
387 | kfree(tk); | |
388 | } | |
389 | } | |
390 | ||
3ba08129 NH |
391 | /* |
392 | * Find a dedicated thread which is supposed to handle SIGBUS(BUS_MCEERR_AO) | |
393 | * on behalf of the thread group. Return task_struct of the (first found) | |
394 | * dedicated thread if found, and return NULL otherwise. | |
395 | * | |
396 | * We already hold read_lock(&tasklist_lock) in the caller, so we don't | |
397 | * have to call rcu_read_lock/unlock() in this function. | |
398 | */ | |
399 | static struct task_struct *find_early_kill_thread(struct task_struct *tsk) | |
6a46079c | 400 | { |
3ba08129 NH |
401 | struct task_struct *t; |
402 | ||
403 | for_each_thread(tsk, t) | |
404 | if ((t->flags & PF_MCE_PROCESS) && (t->flags & PF_MCE_EARLY)) | |
405 | return t; | |
406 | return NULL; | |
407 | } | |
408 | ||
409 | /* | |
410 | * Determine whether a given process is "early kill" process which expects | |
411 | * to be signaled when some page under the process is hwpoisoned. | |
412 | * Return task_struct of the dedicated thread (main thread unless explicitly | |
413 | * specified) if the process is "early kill," and otherwise returns NULL. | |
414 | */ | |
415 | static struct task_struct *task_early_kill(struct task_struct *tsk, | |
416 | int force_early) | |
417 | { | |
418 | struct task_struct *t; | |
6a46079c | 419 | if (!tsk->mm) |
3ba08129 | 420 | return NULL; |
74614de1 | 421 | if (force_early) |
3ba08129 NH |
422 | return tsk; |
423 | t = find_early_kill_thread(tsk); | |
424 | if (t) | |
425 | return t; | |
426 | if (sysctl_memory_failure_early_kill) | |
427 | return tsk; | |
428 | return NULL; | |
6a46079c AK |
429 | } |
430 | ||
431 | /* | |
432 | * Collect processes when the error hit an anonymous page. | |
433 | */ | |
434 | static void collect_procs_anon(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; | |
439 | struct anon_vma *av; | |
bf181b9f | 440 | pgoff_t pgoff; |
6a46079c | 441 | |
4fc3f1d6 | 442 | av = page_lock_anon_vma_read(page); |
6a46079c | 443 | if (av == NULL) /* Not actually mapped anymore */ |
9b679320 PZ |
444 | return; |
445 | ||
a0f7a756 | 446 | pgoff = page_to_pgoff(page); |
9b679320 | 447 | read_lock(&tasklist_lock); |
6a46079c | 448 | for_each_process (tsk) { |
5beb4930 | 449 | struct anon_vma_chain *vmac; |
3ba08129 | 450 | struct task_struct *t = task_early_kill(tsk, force_early); |
5beb4930 | 451 | |
3ba08129 | 452 | if (!t) |
6a46079c | 453 | continue; |
bf181b9f ML |
454 | anon_vma_interval_tree_foreach(vmac, &av->rb_root, |
455 | pgoff, pgoff) { | |
5beb4930 | 456 | vma = vmac->vma; |
6a46079c AK |
457 | if (!page_mapped_in_vma(page, vma)) |
458 | continue; | |
3ba08129 NH |
459 | if (vma->vm_mm == t->mm) |
460 | add_to_kill(t, page, vma, to_kill, tkc); | |
6a46079c AK |
461 | } |
462 | } | |
6a46079c | 463 | read_unlock(&tasklist_lock); |
4fc3f1d6 | 464 | page_unlock_anon_vma_read(av); |
6a46079c AK |
465 | } |
466 | ||
467 | /* | |
468 | * Collect processes when the error hit a file mapped page. | |
469 | */ | |
470 | static void collect_procs_file(struct page *page, struct list_head *to_kill, | |
74614de1 | 471 | struct to_kill **tkc, int force_early) |
6a46079c AK |
472 | { |
473 | struct vm_area_struct *vma; | |
474 | struct task_struct *tsk; | |
6a46079c AK |
475 | struct address_space *mapping = page->mapping; |
476 | ||
d28eb9c8 | 477 | i_mmap_lock_read(mapping); |
9b679320 | 478 | read_lock(&tasklist_lock); |
6a46079c | 479 | for_each_process(tsk) { |
a0f7a756 | 480 | pgoff_t pgoff = page_to_pgoff(page); |
3ba08129 | 481 | struct task_struct *t = task_early_kill(tsk, force_early); |
6a46079c | 482 | |
3ba08129 | 483 | if (!t) |
6a46079c | 484 | continue; |
6b2dbba8 | 485 | vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, |
6a46079c AK |
486 | pgoff) { |
487 | /* | |
488 | * Send early kill signal to tasks where a vma covers | |
489 | * the page but the corrupted page is not necessarily | |
490 | * mapped it in its pte. | |
491 | * Assume applications who requested early kill want | |
492 | * to be informed of all such data corruptions. | |
493 | */ | |
3ba08129 NH |
494 | if (vma->vm_mm == t->mm) |
495 | add_to_kill(t, page, vma, to_kill, tkc); | |
6a46079c AK |
496 | } |
497 | } | |
6a46079c | 498 | read_unlock(&tasklist_lock); |
d28eb9c8 | 499 | i_mmap_unlock_read(mapping); |
6a46079c AK |
500 | } |
501 | ||
502 | /* | |
503 | * Collect the processes who have the corrupted page mapped to kill. | |
504 | * This is done in two steps for locking reasons. | |
505 | * First preallocate one tokill structure outside the spin locks, | |
506 | * so that we can kill at least one process reasonably reliable. | |
507 | */ | |
74614de1 TL |
508 | static void collect_procs(struct page *page, struct list_head *tokill, |
509 | int force_early) | |
6a46079c AK |
510 | { |
511 | struct to_kill *tk; | |
512 | ||
513 | if (!page->mapping) | |
514 | return; | |
515 | ||
516 | tk = kmalloc(sizeof(struct to_kill), GFP_NOIO); | |
517 | if (!tk) | |
518 | return; | |
519 | if (PageAnon(page)) | |
74614de1 | 520 | collect_procs_anon(page, tokill, &tk, force_early); |
6a46079c | 521 | else |
74614de1 | 522 | collect_procs_file(page, tokill, &tk, force_early); |
6a46079c AK |
523 | kfree(tk); |
524 | } | |
525 | ||
6a46079c | 526 | static const char *action_name[] = { |
cc637b17 XX |
527 | [MF_IGNORED] = "Ignored", |
528 | [MF_FAILED] = "Failed", | |
529 | [MF_DELAYED] = "Delayed", | |
530 | [MF_RECOVERED] = "Recovered", | |
64d37a2b NH |
531 | }; |
532 | ||
533 | static const char * const action_page_types[] = { | |
cc637b17 XX |
534 | [MF_MSG_KERNEL] = "reserved kernel page", |
535 | [MF_MSG_KERNEL_HIGH_ORDER] = "high-order kernel page", | |
536 | [MF_MSG_SLAB] = "kernel slab page", | |
537 | [MF_MSG_DIFFERENT_COMPOUND] = "different compound page after locking", | |
538 | [MF_MSG_POISONED_HUGE] = "huge page already hardware poisoned", | |
539 | [MF_MSG_HUGE] = "huge page", | |
540 | [MF_MSG_FREE_HUGE] = "free huge page", | |
31286a84 | 541 | [MF_MSG_NON_PMD_HUGE] = "non-pmd-sized huge page", |
cc637b17 XX |
542 | [MF_MSG_UNMAP_FAILED] = "unmapping failed page", |
543 | [MF_MSG_DIRTY_SWAPCACHE] = "dirty swapcache page", | |
544 | [MF_MSG_CLEAN_SWAPCACHE] = "clean swapcache page", | |
545 | [MF_MSG_DIRTY_MLOCKED_LRU] = "dirty mlocked LRU page", | |
546 | [MF_MSG_CLEAN_MLOCKED_LRU] = "clean mlocked LRU page", | |
547 | [MF_MSG_DIRTY_UNEVICTABLE_LRU] = "dirty unevictable LRU page", | |
548 | [MF_MSG_CLEAN_UNEVICTABLE_LRU] = "clean unevictable LRU page", | |
549 | [MF_MSG_DIRTY_LRU] = "dirty LRU page", | |
550 | [MF_MSG_CLEAN_LRU] = "clean LRU page", | |
551 | [MF_MSG_TRUNCATED_LRU] = "already truncated LRU page", | |
552 | [MF_MSG_BUDDY] = "free buddy page", | |
553 | [MF_MSG_BUDDY_2ND] = "free buddy page (2nd try)", | |
6100e34b | 554 | [MF_MSG_DAX] = "dax page", |
cc637b17 | 555 | [MF_MSG_UNKNOWN] = "unknown page", |
64d37a2b NH |
556 | }; |
557 | ||
dc2a1cbf WF |
558 | /* |
559 | * XXX: It is possible that a page is isolated from LRU cache, | |
560 | * and then kept in swap cache or failed to remove from page cache. | |
561 | * The page count will stop it from being freed by unpoison. | |
562 | * Stress tests should be aware of this memory leak problem. | |
563 | */ | |
564 | static int delete_from_lru_cache(struct page *p) | |
565 | { | |
566 | if (!isolate_lru_page(p)) { | |
567 | /* | |
568 | * Clear sensible page flags, so that the buddy system won't | |
569 | * complain when the page is unpoison-and-freed. | |
570 | */ | |
571 | ClearPageActive(p); | |
572 | ClearPageUnevictable(p); | |
18365225 MH |
573 | |
574 | /* | |
575 | * Poisoned page might never drop its ref count to 0 so we have | |
576 | * to uncharge it manually from its memcg. | |
577 | */ | |
578 | mem_cgroup_uncharge(p); | |
579 | ||
dc2a1cbf WF |
580 | /* |
581 | * drop the page count elevated by isolate_lru_page() | |
582 | */ | |
09cbfeaf | 583 | put_page(p); |
dc2a1cbf WF |
584 | return 0; |
585 | } | |
586 | return -EIO; | |
587 | } | |
588 | ||
78bb9203 NH |
589 | static int truncate_error_page(struct page *p, unsigned long pfn, |
590 | struct address_space *mapping) | |
591 | { | |
592 | int ret = MF_FAILED; | |
593 | ||
594 | if (mapping->a_ops->error_remove_page) { | |
595 | int err = mapping->a_ops->error_remove_page(mapping, p); | |
596 | ||
597 | if (err != 0) { | |
598 | pr_info("Memory failure: %#lx: Failed to punch page: %d\n", | |
599 | pfn, err); | |
600 | } else if (page_has_private(p) && | |
601 | !try_to_release_page(p, GFP_NOIO)) { | |
602 | pr_info("Memory failure: %#lx: failed to release buffers\n", | |
603 | pfn); | |
604 | } else { | |
605 | ret = MF_RECOVERED; | |
606 | } | |
607 | } else { | |
608 | /* | |
609 | * If the file system doesn't support it just invalidate | |
610 | * This fails on dirty or anything with private pages | |
611 | */ | |
612 | if (invalidate_inode_page(p)) | |
613 | ret = MF_RECOVERED; | |
614 | else | |
615 | pr_info("Memory failure: %#lx: Failed to invalidate\n", | |
616 | pfn); | |
617 | } | |
618 | ||
619 | return ret; | |
620 | } | |
621 | ||
6a46079c AK |
622 | /* |
623 | * Error hit kernel page. | |
624 | * Do nothing, try to be lucky and not touch this instead. For a few cases we | |
625 | * could be more sophisticated. | |
626 | */ | |
627 | static int me_kernel(struct page *p, unsigned long pfn) | |
6a46079c | 628 | { |
cc637b17 | 629 | return MF_IGNORED; |
6a46079c AK |
630 | } |
631 | ||
632 | /* | |
633 | * Page in unknown state. Do nothing. | |
634 | */ | |
635 | static int me_unknown(struct page *p, unsigned long pfn) | |
636 | { | |
495367c0 | 637 | pr_err("Memory failure: %#lx: Unknown page state\n", pfn); |
cc637b17 | 638 | return MF_FAILED; |
6a46079c AK |
639 | } |
640 | ||
6a46079c AK |
641 | /* |
642 | * Clean (or cleaned) page cache page. | |
643 | */ | |
644 | static int me_pagecache_clean(struct page *p, unsigned long pfn) | |
645 | { | |
6a46079c AK |
646 | struct address_space *mapping; |
647 | ||
dc2a1cbf WF |
648 | delete_from_lru_cache(p); |
649 | ||
6a46079c AK |
650 | /* |
651 | * For anonymous pages we're done the only reference left | |
652 | * should be the one m_f() holds. | |
653 | */ | |
654 | if (PageAnon(p)) | |
cc637b17 | 655 | return MF_RECOVERED; |
6a46079c AK |
656 | |
657 | /* | |
658 | * Now truncate the page in the page cache. This is really | |
659 | * more like a "temporary hole punch" | |
660 | * Don't do this for block devices when someone else | |
661 | * has a reference, because it could be file system metadata | |
662 | * and that's not safe to truncate. | |
663 | */ | |
664 | mapping = page_mapping(p); | |
665 | if (!mapping) { | |
666 | /* | |
667 | * Page has been teared down in the meanwhile | |
668 | */ | |
cc637b17 | 669 | return MF_FAILED; |
6a46079c AK |
670 | } |
671 | ||
672 | /* | |
673 | * Truncation is a bit tricky. Enable it per file system for now. | |
674 | * | |
675 | * Open: to take i_mutex or not for this? Right now we don't. | |
676 | */ | |
78bb9203 | 677 | return truncate_error_page(p, pfn, mapping); |
6a46079c AK |
678 | } |
679 | ||
680 | /* | |
549543df | 681 | * Dirty pagecache page |
6a46079c AK |
682 | * Issues: when the error hit a hole page the error is not properly |
683 | * propagated. | |
684 | */ | |
685 | static int me_pagecache_dirty(struct page *p, unsigned long pfn) | |
686 | { | |
687 | struct address_space *mapping = page_mapping(p); | |
688 | ||
689 | SetPageError(p); | |
690 | /* TBD: print more information about the file. */ | |
691 | if (mapping) { | |
692 | /* | |
693 | * IO error will be reported by write(), fsync(), etc. | |
694 | * who check the mapping. | |
695 | * This way the application knows that something went | |
696 | * wrong with its dirty file data. | |
697 | * | |
698 | * There's one open issue: | |
699 | * | |
700 | * The EIO will be only reported on the next IO | |
701 | * operation and then cleared through the IO map. | |
702 | * Normally Linux has two mechanisms to pass IO error | |
703 | * first through the AS_EIO flag in the address space | |
704 | * and then through the PageError flag in the page. | |
705 | * Since we drop pages on memory failure handling the | |
706 | * only mechanism open to use is through AS_AIO. | |
707 | * | |
708 | * This has the disadvantage that it gets cleared on | |
709 | * the first operation that returns an error, while | |
710 | * the PageError bit is more sticky and only cleared | |
711 | * when the page is reread or dropped. If an | |
712 | * application assumes it will always get error on | |
713 | * fsync, but does other operations on the fd before | |
25985edc | 714 | * and the page is dropped between then the error |
6a46079c AK |
715 | * will not be properly reported. |
716 | * | |
717 | * This can already happen even without hwpoisoned | |
718 | * pages: first on metadata IO errors (which only | |
719 | * report through AS_EIO) or when the page is dropped | |
720 | * at the wrong time. | |
721 | * | |
722 | * So right now we assume that the application DTRT on | |
723 | * the first EIO, but we're not worse than other parts | |
724 | * of the kernel. | |
725 | */ | |
af21bfaf | 726 | mapping_set_error(mapping, -EIO); |
6a46079c AK |
727 | } |
728 | ||
729 | return me_pagecache_clean(p, pfn); | |
730 | } | |
731 | ||
732 | /* | |
733 | * Clean and dirty swap cache. | |
734 | * | |
735 | * Dirty swap cache page is tricky to handle. The page could live both in page | |
736 | * cache and swap cache(ie. page is freshly swapped in). So it could be | |
737 | * referenced concurrently by 2 types of PTEs: | |
738 | * normal PTEs and swap PTEs. We try to handle them consistently by calling | |
739 | * try_to_unmap(TTU_IGNORE_HWPOISON) to convert the normal PTEs to swap PTEs, | |
740 | * and then | |
741 | * - clear dirty bit to prevent IO | |
742 | * - remove from LRU | |
743 | * - but keep in the swap cache, so that when we return to it on | |
744 | * a later page fault, we know the application is accessing | |
745 | * corrupted data and shall be killed (we installed simple | |
746 | * interception code in do_swap_page to catch it). | |
747 | * | |
748 | * Clean swap cache pages can be directly isolated. A later page fault will | |
749 | * bring in the known good data from disk. | |
750 | */ | |
751 | static int me_swapcache_dirty(struct page *p, unsigned long pfn) | |
752 | { | |
6a46079c AK |
753 | ClearPageDirty(p); |
754 | /* Trigger EIO in shmem: */ | |
755 | ClearPageUptodate(p); | |
756 | ||
dc2a1cbf | 757 | if (!delete_from_lru_cache(p)) |
cc637b17 | 758 | return MF_DELAYED; |
dc2a1cbf | 759 | else |
cc637b17 | 760 | return MF_FAILED; |
6a46079c AK |
761 | } |
762 | ||
763 | static int me_swapcache_clean(struct page *p, unsigned long pfn) | |
764 | { | |
6a46079c | 765 | delete_from_swap_cache(p); |
e43c3afb | 766 | |
dc2a1cbf | 767 | if (!delete_from_lru_cache(p)) |
cc637b17 | 768 | return MF_RECOVERED; |
dc2a1cbf | 769 | else |
cc637b17 | 770 | return MF_FAILED; |
6a46079c AK |
771 | } |
772 | ||
773 | /* | |
774 | * Huge pages. Needs work. | |
775 | * Issues: | |
93f70f90 NH |
776 | * - Error on hugepage is contained in hugepage unit (not in raw page unit.) |
777 | * To narrow down kill region to one page, we need to break up pmd. | |
6a46079c AK |
778 | */ |
779 | static int me_huge_page(struct page *p, unsigned long pfn) | |
780 | { | |
6de2b1aa | 781 | int res = 0; |
93f70f90 | 782 | struct page *hpage = compound_head(p); |
78bb9203 | 783 | struct address_space *mapping; |
2491ffee NH |
784 | |
785 | if (!PageHuge(hpage)) | |
786 | return MF_DELAYED; | |
787 | ||
78bb9203 NH |
788 | mapping = page_mapping(hpage); |
789 | if (mapping) { | |
790 | res = truncate_error_page(hpage, pfn, mapping); | |
791 | } else { | |
792 | unlock_page(hpage); | |
793 | /* | |
794 | * migration entry prevents later access on error anonymous | |
795 | * hugepage, so we can free and dissolve it into buddy to | |
796 | * save healthy subpages. | |
797 | */ | |
798 | if (PageAnon(hpage)) | |
799 | put_page(hpage); | |
800 | dissolve_free_huge_page(p); | |
801 | res = MF_RECOVERED; | |
802 | lock_page(hpage); | |
93f70f90 | 803 | } |
78bb9203 NH |
804 | |
805 | return res; | |
6a46079c AK |
806 | } |
807 | ||
808 | /* | |
809 | * Various page states we can handle. | |
810 | * | |
811 | * A page state is defined by its current page->flags bits. | |
812 | * The table matches them in order and calls the right handler. | |
813 | * | |
814 | * This is quite tricky because we can access page at any time | |
25985edc | 815 | * in its live cycle, so all accesses have to be extremely careful. |
6a46079c AK |
816 | * |
817 | * This is not complete. More states could be added. | |
818 | * For any missing state don't attempt recovery. | |
819 | */ | |
820 | ||
821 | #define dirty (1UL << PG_dirty) | |
6326fec1 | 822 | #define sc ((1UL << PG_swapcache) | (1UL << PG_swapbacked)) |
6a46079c AK |
823 | #define unevict (1UL << PG_unevictable) |
824 | #define mlock (1UL << PG_mlocked) | |
825 | #define writeback (1UL << PG_writeback) | |
826 | #define lru (1UL << PG_lru) | |
6a46079c | 827 | #define head (1UL << PG_head) |
6a46079c | 828 | #define slab (1UL << PG_slab) |
6a46079c AK |
829 | #define reserved (1UL << PG_reserved) |
830 | ||
831 | static struct page_state { | |
832 | unsigned long mask; | |
833 | unsigned long res; | |
cc637b17 | 834 | enum mf_action_page_type type; |
6a46079c AK |
835 | int (*action)(struct page *p, unsigned long pfn); |
836 | } error_states[] = { | |
cc637b17 | 837 | { reserved, reserved, MF_MSG_KERNEL, me_kernel }, |
95d01fc6 WF |
838 | /* |
839 | * free pages are specially detected outside this table: | |
840 | * PG_buddy pages only make a small fraction of all free pages. | |
841 | */ | |
6a46079c AK |
842 | |
843 | /* | |
844 | * Could in theory check if slab page is free or if we can drop | |
845 | * currently unused objects without touching them. But just | |
846 | * treat it as standard kernel for now. | |
847 | */ | |
cc637b17 | 848 | { slab, slab, MF_MSG_SLAB, me_kernel }, |
6a46079c | 849 | |
cc637b17 | 850 | { head, head, MF_MSG_HUGE, me_huge_page }, |
6a46079c | 851 | |
cc637b17 XX |
852 | { sc|dirty, sc|dirty, MF_MSG_DIRTY_SWAPCACHE, me_swapcache_dirty }, |
853 | { sc|dirty, sc, MF_MSG_CLEAN_SWAPCACHE, me_swapcache_clean }, | |
6a46079c | 854 | |
cc637b17 XX |
855 | { mlock|dirty, mlock|dirty, MF_MSG_DIRTY_MLOCKED_LRU, me_pagecache_dirty }, |
856 | { mlock|dirty, mlock, MF_MSG_CLEAN_MLOCKED_LRU, me_pagecache_clean }, | |
6a46079c | 857 | |
cc637b17 XX |
858 | { unevict|dirty, unevict|dirty, MF_MSG_DIRTY_UNEVICTABLE_LRU, me_pagecache_dirty }, |
859 | { unevict|dirty, unevict, MF_MSG_CLEAN_UNEVICTABLE_LRU, me_pagecache_clean }, | |
5f4b9fc5 | 860 | |
cc637b17 XX |
861 | { lru|dirty, lru|dirty, MF_MSG_DIRTY_LRU, me_pagecache_dirty }, |
862 | { lru|dirty, lru, MF_MSG_CLEAN_LRU, me_pagecache_clean }, | |
6a46079c AK |
863 | |
864 | /* | |
865 | * Catchall entry: must be at end. | |
866 | */ | |
cc637b17 | 867 | { 0, 0, MF_MSG_UNKNOWN, me_unknown }, |
6a46079c AK |
868 | }; |
869 | ||
2326c467 AK |
870 | #undef dirty |
871 | #undef sc | |
872 | #undef unevict | |
873 | #undef mlock | |
874 | #undef writeback | |
875 | #undef lru | |
2326c467 | 876 | #undef head |
2326c467 AK |
877 | #undef slab |
878 | #undef reserved | |
879 | ||
ff604cf6 NH |
880 | /* |
881 | * "Dirty/Clean" indication is not 100% accurate due to the possibility of | |
882 | * setting PG_dirty outside page lock. See also comment above set_page_dirty(). | |
883 | */ | |
cc3e2af4 XX |
884 | static void action_result(unsigned long pfn, enum mf_action_page_type type, |
885 | enum mf_result result) | |
6a46079c | 886 | { |
97f0b134 XX |
887 | trace_memory_failure_event(pfn, type, result); |
888 | ||
495367c0 | 889 | pr_err("Memory failure: %#lx: recovery action for %s: %s\n", |
64d37a2b | 890 | pfn, action_page_types[type], action_name[result]); |
6a46079c AK |
891 | } |
892 | ||
893 | static int page_action(struct page_state *ps, struct page *p, | |
bd1ce5f9 | 894 | unsigned long pfn) |
6a46079c AK |
895 | { |
896 | int result; | |
7456b040 | 897 | int count; |
6a46079c AK |
898 | |
899 | result = ps->action(p, pfn); | |
7456b040 | 900 | |
bd1ce5f9 | 901 | count = page_count(p) - 1; |
cc637b17 | 902 | if (ps->action == me_swapcache_dirty && result == MF_DELAYED) |
138ce286 | 903 | count--; |
78bb9203 | 904 | if (count > 0) { |
495367c0 | 905 | pr_err("Memory failure: %#lx: %s still referenced by %d users\n", |
64d37a2b | 906 | pfn, action_page_types[ps->type], count); |
cc637b17 | 907 | result = MF_FAILED; |
138ce286 | 908 | } |
64d37a2b | 909 | action_result(pfn, ps->type, result); |
6a46079c AK |
910 | |
911 | /* Could do more checks here if page looks ok */ | |
912 | /* | |
913 | * Could adjust zone counters here to correct for the missing page. | |
914 | */ | |
915 | ||
cc637b17 | 916 | return (result == MF_RECOVERED || result == MF_DELAYED) ? 0 : -EBUSY; |
6a46079c AK |
917 | } |
918 | ||
ead07f6a NH |
919 | /** |
920 | * get_hwpoison_page() - Get refcount for memory error handling: | |
921 | * @page: raw error page (hit by memory error) | |
922 | * | |
923 | * Return: return 0 if failed to grab the refcount, otherwise true (some | |
924 | * non-zero value.) | |
925 | */ | |
926 | int get_hwpoison_page(struct page *page) | |
927 | { | |
928 | struct page *head = compound_head(page); | |
929 | ||
4e41a30c | 930 | if (!PageHuge(head) && PageTransHuge(head)) { |
98ed2b00 NH |
931 | /* |
932 | * Non anonymous thp exists only in allocation/free time. We | |
933 | * can't handle such a case correctly, so let's give it up. | |
934 | * This should be better than triggering BUG_ON when kernel | |
935 | * tries to touch the "partially handled" page. | |
936 | */ | |
937 | if (!PageAnon(head)) { | |
495367c0 | 938 | pr_err("Memory failure: %#lx: non anonymous thp\n", |
98ed2b00 NH |
939 | page_to_pfn(page)); |
940 | return 0; | |
941 | } | |
ead07f6a NH |
942 | } |
943 | ||
c2e7e00b KK |
944 | if (get_page_unless_zero(head)) { |
945 | if (head == compound_head(page)) | |
946 | return 1; | |
947 | ||
495367c0 CY |
948 | pr_info("Memory failure: %#lx cannot catch tail\n", |
949 | page_to_pfn(page)); | |
c2e7e00b KK |
950 | put_page(head); |
951 | } | |
952 | ||
953 | return 0; | |
ead07f6a NH |
954 | } |
955 | EXPORT_SYMBOL_GPL(get_hwpoison_page); | |
956 | ||
6a46079c AK |
957 | /* |
958 | * Do all that is necessary to remove user space mappings. Unmap | |
959 | * the pages and send SIGBUS to the processes if the data was dirty. | |
960 | */ | |
666e5a40 | 961 | static bool hwpoison_user_mappings(struct page *p, unsigned long pfn, |
83b57531 | 962 | int flags, struct page **hpagep) |
6a46079c | 963 | { |
a128ca71 | 964 | enum ttu_flags ttu = TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS; |
6a46079c AK |
965 | struct address_space *mapping; |
966 | LIST_HEAD(tokill); | |
ddeaab32 | 967 | bool unmap_success; |
6751ed65 | 968 | int kill = 1, forcekill; |
54b9dd14 | 969 | struct page *hpage = *hpagep; |
286c469a | 970 | bool mlocked = PageMlocked(hpage); |
6a46079c | 971 | |
93a9eb39 NH |
972 | /* |
973 | * Here we are interested only in user-mapped pages, so skip any | |
974 | * other types of pages. | |
975 | */ | |
976 | if (PageReserved(p) || PageSlab(p)) | |
666e5a40 | 977 | return true; |
93a9eb39 | 978 | if (!(PageLRU(hpage) || PageHuge(p))) |
666e5a40 | 979 | return true; |
6a46079c | 980 | |
6a46079c AK |
981 | /* |
982 | * This check implies we don't kill processes if their pages | |
983 | * are in the swap cache early. Those are always late kills. | |
984 | */ | |
7af446a8 | 985 | if (!page_mapped(hpage)) |
666e5a40 | 986 | return true; |
1668bfd5 | 987 | |
52089b14 | 988 | if (PageKsm(p)) { |
495367c0 | 989 | pr_err("Memory failure: %#lx: can't handle KSM pages.\n", pfn); |
666e5a40 | 990 | return false; |
52089b14 | 991 | } |
6a46079c AK |
992 | |
993 | if (PageSwapCache(p)) { | |
495367c0 CY |
994 | pr_err("Memory failure: %#lx: keeping poisoned page in swap cache\n", |
995 | pfn); | |
6a46079c AK |
996 | ttu |= TTU_IGNORE_HWPOISON; |
997 | } | |
998 | ||
999 | /* | |
1000 | * Propagate the dirty bit from PTEs to struct page first, because we | |
1001 | * need this to decide if we should kill or just drop the page. | |
db0480b3 WF |
1002 | * XXX: the dirty test could be racy: set_page_dirty() may not always |
1003 | * be called inside page lock (it's recommended but not enforced). | |
6a46079c | 1004 | */ |
7af446a8 | 1005 | mapping = page_mapping(hpage); |
6751ed65 | 1006 | if (!(flags & MF_MUST_KILL) && !PageDirty(hpage) && mapping && |
7af446a8 NH |
1007 | mapping_cap_writeback_dirty(mapping)) { |
1008 | if (page_mkclean(hpage)) { | |
1009 | SetPageDirty(hpage); | |
6a46079c AK |
1010 | } else { |
1011 | kill = 0; | |
1012 | ttu |= TTU_IGNORE_HWPOISON; | |
495367c0 | 1013 | pr_info("Memory failure: %#lx: corrupted page was clean: dropped without side effects\n", |
6a46079c AK |
1014 | pfn); |
1015 | } | |
1016 | } | |
1017 | ||
1018 | /* | |
1019 | * First collect all the processes that have the page | |
1020 | * mapped in dirty form. This has to be done before try_to_unmap, | |
1021 | * because ttu takes the rmap data structures down. | |
1022 | * | |
1023 | * Error handling: We ignore errors here because | |
1024 | * there's nothing that can be done. | |
1025 | */ | |
1026 | if (kill) | |
415c64c1 | 1027 | collect_procs(hpage, &tokill, flags & MF_ACTION_REQUIRED); |
6a46079c | 1028 | |
ddeaab32 | 1029 | unmap_success = try_to_unmap(hpage, ttu); |
666e5a40 | 1030 | if (!unmap_success) |
495367c0 | 1031 | pr_err("Memory failure: %#lx: failed to unmap page (mapcount=%d)\n", |
1170532b | 1032 | pfn, page_mapcount(hpage)); |
a6d30ddd | 1033 | |
286c469a NH |
1034 | /* |
1035 | * try_to_unmap() might put mlocked page in lru cache, so call | |
1036 | * shake_page() again to ensure that it's flushed. | |
1037 | */ | |
1038 | if (mlocked) | |
1039 | shake_page(hpage, 0); | |
1040 | ||
6a46079c AK |
1041 | /* |
1042 | * Now that the dirty bit has been propagated to the | |
1043 | * struct page and all unmaps done we can decide if | |
1044 | * killing is needed or not. Only kill when the page | |
6751ed65 TL |
1045 | * was dirty or the process is not restartable, |
1046 | * otherwise the tokill list is merely | |
6a46079c AK |
1047 | * freed. When there was a problem unmapping earlier |
1048 | * use a more force-full uncatchable kill to prevent | |
1049 | * any accesses to the poisoned memory. | |
1050 | */ | |
415c64c1 | 1051 | forcekill = PageDirty(hpage) || (flags & MF_MUST_KILL); |
ae1139ec | 1052 | kill_procs(&tokill, forcekill, !unmap_success, pfn, flags); |
1668bfd5 | 1053 | |
666e5a40 | 1054 | return unmap_success; |
6a46079c AK |
1055 | } |
1056 | ||
0348d2eb NH |
1057 | static int identify_page_state(unsigned long pfn, struct page *p, |
1058 | unsigned long page_flags) | |
761ad8d7 NH |
1059 | { |
1060 | struct page_state *ps; | |
0348d2eb NH |
1061 | |
1062 | /* | |
1063 | * The first check uses the current page flags which may not have any | |
1064 | * relevant information. The second check with the saved page flags is | |
1065 | * carried out only if the first check can't determine the page status. | |
1066 | */ | |
1067 | for (ps = error_states;; ps++) | |
1068 | if ((p->flags & ps->mask) == ps->res) | |
1069 | break; | |
1070 | ||
1071 | page_flags |= (p->flags & (1UL << PG_dirty)); | |
1072 | ||
1073 | if (!ps->mask) | |
1074 | for (ps = error_states;; ps++) | |
1075 | if ((page_flags & ps->mask) == ps->res) | |
1076 | break; | |
1077 | return page_action(ps, p, pfn); | |
1078 | } | |
1079 | ||
83b57531 | 1080 | static int memory_failure_hugetlb(unsigned long pfn, int flags) |
0348d2eb | 1081 | { |
761ad8d7 NH |
1082 | struct page *p = pfn_to_page(pfn); |
1083 | struct page *head = compound_head(p); | |
1084 | int res; | |
1085 | unsigned long page_flags; | |
1086 | ||
1087 | if (TestSetPageHWPoison(head)) { | |
1088 | pr_err("Memory failure: %#lx: already hardware poisoned\n", | |
1089 | pfn); | |
1090 | return 0; | |
1091 | } | |
1092 | ||
1093 | num_poisoned_pages_inc(); | |
1094 | ||
1095 | if (!(flags & MF_COUNT_INCREASED) && !get_hwpoison_page(p)) { | |
1096 | /* | |
1097 | * Check "filter hit" and "race with other subpage." | |
1098 | */ | |
1099 | lock_page(head); | |
1100 | if (PageHWPoison(head)) { | |
1101 | if ((hwpoison_filter(p) && TestClearPageHWPoison(p)) | |
1102 | || (p != head && TestSetPageHWPoison(head))) { | |
1103 | num_poisoned_pages_dec(); | |
1104 | unlock_page(head); | |
1105 | return 0; | |
1106 | } | |
1107 | } | |
1108 | unlock_page(head); | |
1109 | dissolve_free_huge_page(p); | |
1110 | action_result(pfn, MF_MSG_FREE_HUGE, MF_DELAYED); | |
1111 | return 0; | |
1112 | } | |
1113 | ||
1114 | lock_page(head); | |
1115 | page_flags = head->flags; | |
1116 | ||
1117 | if (!PageHWPoison(head)) { | |
1118 | pr_err("Memory failure: %#lx: just unpoisoned\n", pfn); | |
1119 | num_poisoned_pages_dec(); | |
1120 | unlock_page(head); | |
1121 | put_hwpoison_page(head); | |
1122 | return 0; | |
1123 | } | |
1124 | ||
31286a84 NH |
1125 | /* |
1126 | * TODO: hwpoison for pud-sized hugetlb doesn't work right now, so | |
1127 | * simply disable it. In order to make it work properly, we need | |
1128 | * make sure that: | |
1129 | * - conversion of a pud that maps an error hugetlb into hwpoison | |
1130 | * entry properly works, and | |
1131 | * - other mm code walking over page table is aware of pud-aligned | |
1132 | * hwpoison entries. | |
1133 | */ | |
1134 | if (huge_page_size(page_hstate(head)) > PMD_SIZE) { | |
1135 | action_result(pfn, MF_MSG_NON_PMD_HUGE, MF_IGNORED); | |
1136 | res = -EBUSY; | |
1137 | goto out; | |
1138 | } | |
1139 | ||
83b57531 | 1140 | if (!hwpoison_user_mappings(p, pfn, flags, &head)) { |
761ad8d7 NH |
1141 | action_result(pfn, MF_MSG_UNMAP_FAILED, MF_IGNORED); |
1142 | res = -EBUSY; | |
1143 | goto out; | |
1144 | } | |
1145 | ||
0348d2eb | 1146 | res = identify_page_state(pfn, p, page_flags); |
761ad8d7 NH |
1147 | out: |
1148 | unlock_page(head); | |
1149 | return res; | |
1150 | } | |
1151 | ||
6100e34b DW |
1152 | static int memory_failure_dev_pagemap(unsigned long pfn, int flags, |
1153 | struct dev_pagemap *pgmap) | |
1154 | { | |
1155 | struct page *page = pfn_to_page(pfn); | |
1156 | const bool unmap_success = true; | |
1157 | unsigned long size = 0; | |
1158 | struct to_kill *tk; | |
1159 | LIST_HEAD(tokill); | |
1160 | int rc = -EBUSY; | |
1161 | loff_t start; | |
27359fd6 | 1162 | dax_entry_t cookie; |
6100e34b DW |
1163 | |
1164 | /* | |
1165 | * Prevent the inode from being freed while we are interrogating | |
1166 | * the address_space, typically this would be handled by | |
1167 | * lock_page(), but dax pages do not use the page lock. This | |
1168 | * also prevents changes to the mapping of this pfn until | |
1169 | * poison signaling is complete. | |
1170 | */ | |
27359fd6 MW |
1171 | cookie = dax_lock_page(page); |
1172 | if (!cookie) | |
6100e34b DW |
1173 | goto out; |
1174 | ||
1175 | if (hwpoison_filter(page)) { | |
1176 | rc = 0; | |
1177 | goto unlock; | |
1178 | } | |
1179 | ||
25b2995a | 1180 | if (pgmap->type == MEMORY_DEVICE_PRIVATE) { |
6100e34b DW |
1181 | /* |
1182 | * TODO: Handle HMM pages which may need coordination | |
1183 | * with device-side memory. | |
1184 | */ | |
1185 | goto unlock; | |
6100e34b DW |
1186 | } |
1187 | ||
1188 | /* | |
1189 | * Use this flag as an indication that the dax page has been | |
1190 | * remapped UC to prevent speculative consumption of poison. | |
1191 | */ | |
1192 | SetPageHWPoison(page); | |
1193 | ||
1194 | /* | |
1195 | * Unlike System-RAM there is no possibility to swap in a | |
1196 | * different physical page at a given virtual address, so all | |
1197 | * userspace consumption of ZONE_DEVICE memory necessitates | |
1198 | * SIGBUS (i.e. MF_MUST_KILL) | |
1199 | */ | |
1200 | flags |= MF_ACTION_REQUIRED | MF_MUST_KILL; | |
1201 | collect_procs(page, &tokill, flags & MF_ACTION_REQUIRED); | |
1202 | ||
1203 | list_for_each_entry(tk, &tokill, nd) | |
1204 | if (tk->size_shift) | |
1205 | size = max(size, 1UL << tk->size_shift); | |
1206 | if (size) { | |
1207 | /* | |
1208 | * Unmap the largest mapping to avoid breaking up | |
1209 | * device-dax mappings which are constant size. The | |
1210 | * actual size of the mapping being torn down is | |
1211 | * communicated in siginfo, see kill_proc() | |
1212 | */ | |
1213 | start = (page->index << PAGE_SHIFT) & ~(size - 1); | |
1214 | unmap_mapping_range(page->mapping, start, start + size, 0); | |
1215 | } | |
1216 | kill_procs(&tokill, flags & MF_MUST_KILL, !unmap_success, pfn, flags); | |
1217 | rc = 0; | |
1218 | unlock: | |
27359fd6 | 1219 | dax_unlock_page(page, cookie); |
6100e34b DW |
1220 | out: |
1221 | /* drop pgmap ref acquired in caller */ | |
1222 | put_dev_pagemap(pgmap); | |
1223 | action_result(pfn, MF_MSG_DAX, rc ? MF_FAILED : MF_RECOVERED); | |
1224 | return rc; | |
1225 | } | |
1226 | ||
cd42f4a3 TL |
1227 | /** |
1228 | * memory_failure - Handle memory failure of a page. | |
1229 | * @pfn: Page Number of the corrupted page | |
cd42f4a3 TL |
1230 | * @flags: fine tune action taken |
1231 | * | |
1232 | * This function is called by the low level machine check code | |
1233 | * of an architecture when it detects hardware memory corruption | |
1234 | * of a page. It tries its best to recover, which includes | |
1235 | * dropping pages, killing processes etc. | |
1236 | * | |
1237 | * The function is primarily of use for corruptions that | |
1238 | * happen outside the current execution context (e.g. when | |
1239 | * detected by a background scrubber) | |
1240 | * | |
1241 | * Must run in process context (e.g. a work queue) with interrupts | |
1242 | * enabled and no spinlocks hold. | |
1243 | */ | |
83b57531 | 1244 | int memory_failure(unsigned long pfn, int flags) |
6a46079c | 1245 | { |
6a46079c | 1246 | struct page *p; |
7af446a8 | 1247 | struct page *hpage; |
415c64c1 | 1248 | struct page *orig_head; |
6100e34b | 1249 | struct dev_pagemap *pgmap; |
6a46079c | 1250 | int res; |
524fca1e | 1251 | unsigned long page_flags; |
6a46079c AK |
1252 | |
1253 | if (!sysctl_memory_failure_recovery) | |
83b57531 | 1254 | panic("Memory failure on page %lx", pfn); |
6a46079c AK |
1255 | |
1256 | if (!pfn_valid(pfn)) { | |
495367c0 CY |
1257 | pr_err("Memory failure: %#lx: memory outside kernel control\n", |
1258 | pfn); | |
a7560fc8 | 1259 | return -ENXIO; |
6a46079c AK |
1260 | } |
1261 | ||
6100e34b DW |
1262 | pgmap = get_dev_pagemap(pfn, NULL); |
1263 | if (pgmap) | |
1264 | return memory_failure_dev_pagemap(pfn, flags, pgmap); | |
1265 | ||
6a46079c | 1266 | p = pfn_to_page(pfn); |
761ad8d7 | 1267 | if (PageHuge(p)) |
83b57531 | 1268 | return memory_failure_hugetlb(pfn, flags); |
6a46079c | 1269 | if (TestSetPageHWPoison(p)) { |
495367c0 CY |
1270 | pr_err("Memory failure: %#lx: already hardware poisoned\n", |
1271 | pfn); | |
6a46079c AK |
1272 | return 0; |
1273 | } | |
1274 | ||
761ad8d7 | 1275 | orig_head = hpage = compound_head(p); |
b37ff71c | 1276 | num_poisoned_pages_inc(); |
6a46079c AK |
1277 | |
1278 | /* | |
1279 | * We need/can do nothing about count=0 pages. | |
1280 | * 1) it's a free page, and therefore in safe hand: | |
1281 | * prep_new_page() will be the gate keeper. | |
761ad8d7 | 1282 | * 2) it's part of a non-compound high order page. |
6a46079c AK |
1283 | * Implies some kernel user: cannot stop them from |
1284 | * R/W the page; let's pray that the page has been | |
1285 | * used and will be freed some time later. | |
1286 | * In fact it's dangerous to directly bump up page count from 0, | |
1c4c3b99 | 1287 | * that may make page_ref_freeze()/page_ref_unfreeze() mismatch. |
6a46079c | 1288 | */ |
ead07f6a | 1289 | if (!(flags & MF_COUNT_INCREASED) && !get_hwpoison_page(p)) { |
8d22ba1b | 1290 | if (is_free_buddy_page(p)) { |
cc637b17 | 1291 | action_result(pfn, MF_MSG_BUDDY, MF_DELAYED); |
8d22ba1b WF |
1292 | return 0; |
1293 | } else { | |
cc637b17 | 1294 | action_result(pfn, MF_MSG_KERNEL_HIGH_ORDER, MF_IGNORED); |
8d22ba1b WF |
1295 | return -EBUSY; |
1296 | } | |
6a46079c AK |
1297 | } |
1298 | ||
761ad8d7 | 1299 | if (PageTransHuge(hpage)) { |
c3901e72 NH |
1300 | lock_page(p); |
1301 | if (!PageAnon(p) || unlikely(split_huge_page(p))) { | |
1302 | unlock_page(p); | |
1303 | if (!PageAnon(p)) | |
495367c0 CY |
1304 | pr_err("Memory failure: %#lx: non anonymous thp\n", |
1305 | pfn); | |
7f6bf39b | 1306 | else |
495367c0 CY |
1307 | pr_err("Memory failure: %#lx: thp split failed\n", |
1308 | pfn); | |
ead07f6a | 1309 | if (TestClearPageHWPoison(p)) |
b37ff71c | 1310 | num_poisoned_pages_dec(); |
665d9da7 | 1311 | put_hwpoison_page(p); |
415c64c1 NH |
1312 | return -EBUSY; |
1313 | } | |
c3901e72 | 1314 | unlock_page(p); |
415c64c1 NH |
1315 | VM_BUG_ON_PAGE(!page_count(p), p); |
1316 | hpage = compound_head(p); | |
1317 | } | |
1318 | ||
e43c3afb WF |
1319 | /* |
1320 | * We ignore non-LRU pages for good reasons. | |
1321 | * - PG_locked is only well defined for LRU pages and a few others | |
48c935ad | 1322 | * - to avoid races with __SetPageLocked() |
e43c3afb WF |
1323 | * - to avoid races with __SetPageSlab*() (and more non-atomic ops) |
1324 | * The check (unnecessarily) ignores LRU pages being isolated and | |
1325 | * walked by the page reclaim code, however that's not a big loss. | |
1326 | */ | |
8bcb74de NH |
1327 | shake_page(p, 0); |
1328 | /* shake_page could have turned it free. */ | |
1329 | if (!PageLRU(p) && is_free_buddy_page(p)) { | |
1330 | if (flags & MF_COUNT_INCREASED) | |
1331 | action_result(pfn, MF_MSG_BUDDY, MF_DELAYED); | |
1332 | else | |
1333 | action_result(pfn, MF_MSG_BUDDY_2ND, MF_DELAYED); | |
1334 | return 0; | |
e43c3afb | 1335 | } |
e43c3afb | 1336 | |
761ad8d7 | 1337 | lock_page(p); |
847ce401 | 1338 | |
f37d4298 AK |
1339 | /* |
1340 | * The page could have changed compound pages during the locking. | |
1341 | * If this happens just bail out. | |
1342 | */ | |
415c64c1 | 1343 | if (PageCompound(p) && compound_head(p) != orig_head) { |
cc637b17 | 1344 | action_result(pfn, MF_MSG_DIFFERENT_COMPOUND, MF_IGNORED); |
f37d4298 AK |
1345 | res = -EBUSY; |
1346 | goto out; | |
1347 | } | |
1348 | ||
524fca1e NH |
1349 | /* |
1350 | * We use page flags to determine what action should be taken, but | |
1351 | * the flags can be modified by the error containment action. One | |
1352 | * example is an mlocked page, where PG_mlocked is cleared by | |
1353 | * page_remove_rmap() in try_to_unmap_one(). So to determine page status | |
1354 | * correctly, we save a copy of the page flags at this time. | |
1355 | */ | |
7258ae5c JM |
1356 | if (PageHuge(p)) |
1357 | page_flags = hpage->flags; | |
1358 | else | |
1359 | page_flags = p->flags; | |
524fca1e | 1360 | |
847ce401 WF |
1361 | /* |
1362 | * unpoison always clear PG_hwpoison inside page lock | |
1363 | */ | |
1364 | if (!PageHWPoison(p)) { | |
495367c0 | 1365 | pr_err("Memory failure: %#lx: just unpoisoned\n", pfn); |
b37ff71c | 1366 | num_poisoned_pages_dec(); |
761ad8d7 NH |
1367 | unlock_page(p); |
1368 | put_hwpoison_page(p); | |
a09233f3 | 1369 | return 0; |
847ce401 | 1370 | } |
7c116f2b WF |
1371 | if (hwpoison_filter(p)) { |
1372 | if (TestClearPageHWPoison(p)) | |
b37ff71c | 1373 | num_poisoned_pages_dec(); |
761ad8d7 NH |
1374 | unlock_page(p); |
1375 | put_hwpoison_page(p); | |
7c116f2b WF |
1376 | return 0; |
1377 | } | |
847ce401 | 1378 | |
761ad8d7 | 1379 | if (!PageTransTail(p) && !PageLRU(p)) |
0bc1f8b0 CY |
1380 | goto identify_page_state; |
1381 | ||
6edd6cc6 NH |
1382 | /* |
1383 | * It's very difficult to mess with pages currently under IO | |
1384 | * and in many cases impossible, so we just avoid it here. | |
1385 | */ | |
6a46079c AK |
1386 | wait_on_page_writeback(p); |
1387 | ||
1388 | /* | |
1389 | * Now take care of user space mappings. | |
e64a782f | 1390 | * Abort on fail: __delete_from_page_cache() assumes unmapped page. |
54b9dd14 NH |
1391 | * |
1392 | * When the raw error page is thp tail page, hpage points to the raw | |
1393 | * page after thp split. | |
6a46079c | 1394 | */ |
83b57531 | 1395 | if (!hwpoison_user_mappings(p, pfn, flags, &hpage)) { |
cc637b17 | 1396 | action_result(pfn, MF_MSG_UNMAP_FAILED, MF_IGNORED); |
1668bfd5 WF |
1397 | res = -EBUSY; |
1398 | goto out; | |
1399 | } | |
6a46079c AK |
1400 | |
1401 | /* | |
1402 | * Torn down by someone else? | |
1403 | */ | |
dc2a1cbf | 1404 | if (PageLRU(p) && !PageSwapCache(p) && p->mapping == NULL) { |
cc637b17 | 1405 | action_result(pfn, MF_MSG_TRUNCATED_LRU, MF_IGNORED); |
d95ea51e | 1406 | res = -EBUSY; |
6a46079c AK |
1407 | goto out; |
1408 | } | |
1409 | ||
0bc1f8b0 | 1410 | identify_page_state: |
0348d2eb | 1411 | res = identify_page_state(pfn, p, page_flags); |
6a46079c | 1412 | out: |
761ad8d7 | 1413 | unlock_page(p); |
6a46079c AK |
1414 | return res; |
1415 | } | |
cd42f4a3 | 1416 | EXPORT_SYMBOL_GPL(memory_failure); |
847ce401 | 1417 | |
ea8f5fb8 HY |
1418 | #define MEMORY_FAILURE_FIFO_ORDER 4 |
1419 | #define MEMORY_FAILURE_FIFO_SIZE (1 << MEMORY_FAILURE_FIFO_ORDER) | |
1420 | ||
1421 | struct memory_failure_entry { | |
1422 | unsigned long pfn; | |
ea8f5fb8 HY |
1423 | int flags; |
1424 | }; | |
1425 | ||
1426 | struct memory_failure_cpu { | |
1427 | DECLARE_KFIFO(fifo, struct memory_failure_entry, | |
1428 | MEMORY_FAILURE_FIFO_SIZE); | |
1429 | spinlock_t lock; | |
1430 | struct work_struct work; | |
1431 | }; | |
1432 | ||
1433 | static DEFINE_PER_CPU(struct memory_failure_cpu, memory_failure_cpu); | |
1434 | ||
1435 | /** | |
1436 | * memory_failure_queue - Schedule handling memory failure of a page. | |
1437 | * @pfn: Page Number of the corrupted page | |
ea8f5fb8 HY |
1438 | * @flags: Flags for memory failure handling |
1439 | * | |
1440 | * This function is called by the low level hardware error handler | |
1441 | * when it detects hardware memory corruption of a page. It schedules | |
1442 | * the recovering of error page, including dropping pages, killing | |
1443 | * processes etc. | |
1444 | * | |
1445 | * The function is primarily of use for corruptions that | |
1446 | * happen outside the current execution context (e.g. when | |
1447 | * detected by a background scrubber) | |
1448 | * | |
1449 | * Can run in IRQ context. | |
1450 | */ | |
83b57531 | 1451 | void memory_failure_queue(unsigned long pfn, int flags) |
ea8f5fb8 HY |
1452 | { |
1453 | struct memory_failure_cpu *mf_cpu; | |
1454 | unsigned long proc_flags; | |
1455 | struct memory_failure_entry entry = { | |
1456 | .pfn = pfn, | |
ea8f5fb8 HY |
1457 | .flags = flags, |
1458 | }; | |
1459 | ||
1460 | mf_cpu = &get_cpu_var(memory_failure_cpu); | |
1461 | spin_lock_irqsave(&mf_cpu->lock, proc_flags); | |
498d319b | 1462 | if (kfifo_put(&mf_cpu->fifo, entry)) |
ea8f5fb8 HY |
1463 | schedule_work_on(smp_processor_id(), &mf_cpu->work); |
1464 | else | |
8e33a52f | 1465 | pr_err("Memory failure: buffer overflow when queuing memory failure at %#lx\n", |
ea8f5fb8 HY |
1466 | pfn); |
1467 | spin_unlock_irqrestore(&mf_cpu->lock, proc_flags); | |
1468 | put_cpu_var(memory_failure_cpu); | |
1469 | } | |
1470 | EXPORT_SYMBOL_GPL(memory_failure_queue); | |
1471 | ||
1472 | static void memory_failure_work_func(struct work_struct *work) | |
1473 | { | |
1474 | struct memory_failure_cpu *mf_cpu; | |
1475 | struct memory_failure_entry entry = { 0, }; | |
1476 | unsigned long proc_flags; | |
1477 | int gotten; | |
1478 | ||
7c8e0181 | 1479 | mf_cpu = this_cpu_ptr(&memory_failure_cpu); |
ea8f5fb8 HY |
1480 | for (;;) { |
1481 | spin_lock_irqsave(&mf_cpu->lock, proc_flags); | |
1482 | gotten = kfifo_get(&mf_cpu->fifo, &entry); | |
1483 | spin_unlock_irqrestore(&mf_cpu->lock, proc_flags); | |
1484 | if (!gotten) | |
1485 | break; | |
cf870c70 NR |
1486 | if (entry.flags & MF_SOFT_OFFLINE) |
1487 | soft_offline_page(pfn_to_page(entry.pfn), entry.flags); | |
1488 | else | |
83b57531 | 1489 | memory_failure(entry.pfn, entry.flags); |
ea8f5fb8 HY |
1490 | } |
1491 | } | |
1492 | ||
1493 | static int __init memory_failure_init(void) | |
1494 | { | |
1495 | struct memory_failure_cpu *mf_cpu; | |
1496 | int cpu; | |
1497 | ||
1498 | for_each_possible_cpu(cpu) { | |
1499 | mf_cpu = &per_cpu(memory_failure_cpu, cpu); | |
1500 | spin_lock_init(&mf_cpu->lock); | |
1501 | INIT_KFIFO(mf_cpu->fifo); | |
1502 | INIT_WORK(&mf_cpu->work, memory_failure_work_func); | |
1503 | } | |
1504 | ||
1505 | return 0; | |
1506 | } | |
1507 | core_initcall(memory_failure_init); | |
1508 | ||
a5f65109 NH |
1509 | #define unpoison_pr_info(fmt, pfn, rs) \ |
1510 | ({ \ | |
1511 | if (__ratelimit(rs)) \ | |
1512 | pr_info(fmt, pfn); \ | |
1513 | }) | |
1514 | ||
847ce401 WF |
1515 | /** |
1516 | * unpoison_memory - Unpoison a previously poisoned page | |
1517 | * @pfn: Page number of the to be unpoisoned page | |
1518 | * | |
1519 | * Software-unpoison a page that has been poisoned by | |
1520 | * memory_failure() earlier. | |
1521 | * | |
1522 | * This is only done on the software-level, so it only works | |
1523 | * for linux injected failures, not real hardware failures | |
1524 | * | |
1525 | * Returns 0 for success, otherwise -errno. | |
1526 | */ | |
1527 | int unpoison_memory(unsigned long pfn) | |
1528 | { | |
1529 | struct page *page; | |
1530 | struct page *p; | |
1531 | int freeit = 0; | |
a5f65109 NH |
1532 | static DEFINE_RATELIMIT_STATE(unpoison_rs, DEFAULT_RATELIMIT_INTERVAL, |
1533 | DEFAULT_RATELIMIT_BURST); | |
847ce401 WF |
1534 | |
1535 | if (!pfn_valid(pfn)) | |
1536 | return -ENXIO; | |
1537 | ||
1538 | p = pfn_to_page(pfn); | |
1539 | page = compound_head(p); | |
1540 | ||
1541 | if (!PageHWPoison(p)) { | |
495367c0 | 1542 | unpoison_pr_info("Unpoison: Page was already unpoisoned %#lx\n", |
a5f65109 | 1543 | pfn, &unpoison_rs); |
847ce401 WF |
1544 | return 0; |
1545 | } | |
1546 | ||
230ac719 | 1547 | if (page_count(page) > 1) { |
495367c0 | 1548 | unpoison_pr_info("Unpoison: Someone grabs the hwpoison page %#lx\n", |
a5f65109 | 1549 | pfn, &unpoison_rs); |
230ac719 NH |
1550 | return 0; |
1551 | } | |
1552 | ||
1553 | if (page_mapped(page)) { | |
495367c0 | 1554 | unpoison_pr_info("Unpoison: Someone maps the hwpoison page %#lx\n", |
a5f65109 | 1555 | pfn, &unpoison_rs); |
230ac719 NH |
1556 | return 0; |
1557 | } | |
1558 | ||
1559 | if (page_mapping(page)) { | |
495367c0 | 1560 | unpoison_pr_info("Unpoison: the hwpoison page has non-NULL mapping %#lx\n", |
a5f65109 | 1561 | pfn, &unpoison_rs); |
230ac719 NH |
1562 | return 0; |
1563 | } | |
1564 | ||
0cea3fdc WL |
1565 | /* |
1566 | * unpoison_memory() can encounter thp only when the thp is being | |
1567 | * worked by memory_failure() and the page lock is not held yet. | |
1568 | * In such case, we yield to memory_failure() and make unpoison fail. | |
1569 | */ | |
e76d30e2 | 1570 | if (!PageHuge(page) && PageTransHuge(page)) { |
495367c0 | 1571 | unpoison_pr_info("Unpoison: Memory failure is now running on %#lx\n", |
a5f65109 | 1572 | pfn, &unpoison_rs); |
ead07f6a | 1573 | return 0; |
0cea3fdc WL |
1574 | } |
1575 | ||
ead07f6a | 1576 | if (!get_hwpoison_page(p)) { |
847ce401 | 1577 | if (TestClearPageHWPoison(p)) |
8e30456b | 1578 | num_poisoned_pages_dec(); |
495367c0 | 1579 | unpoison_pr_info("Unpoison: Software-unpoisoned free page %#lx\n", |
a5f65109 | 1580 | pfn, &unpoison_rs); |
847ce401 WF |
1581 | return 0; |
1582 | } | |
1583 | ||
7eaceacc | 1584 | lock_page(page); |
847ce401 WF |
1585 | /* |
1586 | * This test is racy because PG_hwpoison is set outside of page lock. | |
1587 | * That's acceptable because that won't trigger kernel panic. Instead, | |
1588 | * the PG_hwpoison page will be caught and isolated on the entrance to | |
1589 | * the free buddy page pool. | |
1590 | */ | |
c9fbdd5f | 1591 | if (TestClearPageHWPoison(page)) { |
495367c0 | 1592 | unpoison_pr_info("Unpoison: Software-unpoisoned page %#lx\n", |
a5f65109 | 1593 | pfn, &unpoison_rs); |
b37ff71c | 1594 | num_poisoned_pages_dec(); |
847ce401 WF |
1595 | freeit = 1; |
1596 | } | |
1597 | unlock_page(page); | |
1598 | ||
665d9da7 | 1599 | put_hwpoison_page(page); |
3ba5eebc | 1600 | if (freeit && !(pfn == my_zero_pfn(0) && page_count(p) == 1)) |
665d9da7 | 1601 | put_hwpoison_page(page); |
847ce401 WF |
1602 | |
1603 | return 0; | |
1604 | } | |
1605 | EXPORT_SYMBOL(unpoison_memory); | |
facb6011 | 1606 | |
666feb21 | 1607 | static struct page *new_page(struct page *p, unsigned long private) |
facb6011 | 1608 | { |
12686d15 | 1609 | int nid = page_to_nid(p); |
94310cbc | 1610 | |
ef77ba5c | 1611 | return new_page_nodemask(p, nid, &node_states[N_MEMORY]); |
facb6011 AK |
1612 | } |
1613 | ||
1614 | /* | |
1615 | * Safely get reference count of an arbitrary page. | |
1616 | * Returns 0 for a free page, -EIO for a zero refcount page | |
1617 | * that is not free, and 1 for any other page type. | |
1618 | * For 1 the page is returned with increased page count, otherwise not. | |
1619 | */ | |
af8fae7c | 1620 | static int __get_any_page(struct page *p, unsigned long pfn, int flags) |
facb6011 AK |
1621 | { |
1622 | int ret; | |
1623 | ||
1624 | if (flags & MF_COUNT_INCREASED) | |
1625 | return 1; | |
1626 | ||
d950b958 NH |
1627 | /* |
1628 | * When the target page is a free hugepage, just remove it | |
1629 | * from free hugepage list. | |
1630 | */ | |
ead07f6a | 1631 | if (!get_hwpoison_page(p)) { |
d950b958 | 1632 | if (PageHuge(p)) { |
71dd0b8a | 1633 | pr_info("%s: %#lx free huge page\n", __func__, pfn); |
af8fae7c | 1634 | ret = 0; |
d950b958 | 1635 | } else if (is_free_buddy_page(p)) { |
71dd0b8a | 1636 | pr_info("%s: %#lx free buddy page\n", __func__, pfn); |
facb6011 AK |
1637 | ret = 0; |
1638 | } else { | |
71dd0b8a BP |
1639 | pr_info("%s: %#lx: unknown zero refcount page type %lx\n", |
1640 | __func__, pfn, p->flags); | |
facb6011 AK |
1641 | ret = -EIO; |
1642 | } | |
1643 | } else { | |
1644 | /* Not a free page */ | |
1645 | ret = 1; | |
1646 | } | |
facb6011 AK |
1647 | return ret; |
1648 | } | |
1649 | ||
af8fae7c NH |
1650 | static int get_any_page(struct page *page, unsigned long pfn, int flags) |
1651 | { | |
1652 | int ret = __get_any_page(page, pfn, flags); | |
1653 | ||
85fbe5d1 YX |
1654 | if (ret == 1 && !PageHuge(page) && |
1655 | !PageLRU(page) && !__PageMovable(page)) { | |
af8fae7c NH |
1656 | /* |
1657 | * Try to free it. | |
1658 | */ | |
665d9da7 | 1659 | put_hwpoison_page(page); |
af8fae7c NH |
1660 | shake_page(page, 1); |
1661 | ||
1662 | /* | |
1663 | * Did it turn free? | |
1664 | */ | |
1665 | ret = __get_any_page(page, pfn, 0); | |
d96b339f | 1666 | if (ret == 1 && !PageLRU(page)) { |
4f32be67 | 1667 | /* Drop page reference which is from __get_any_page() */ |
665d9da7 | 1668 | put_hwpoison_page(page); |
82a2481e AK |
1669 | pr_info("soft_offline: %#lx: unknown non LRU page type %lx (%pGp)\n", |
1670 | pfn, page->flags, &page->flags); | |
af8fae7c NH |
1671 | return -EIO; |
1672 | } | |
1673 | } | |
1674 | return ret; | |
1675 | } | |
1676 | ||
d950b958 NH |
1677 | static int soft_offline_huge_page(struct page *page, int flags) |
1678 | { | |
1679 | int ret; | |
1680 | unsigned long pfn = page_to_pfn(page); | |
1681 | struct page *hpage = compound_head(page); | |
b8ec1cee | 1682 | LIST_HEAD(pagelist); |
d950b958 | 1683 | |
af8fae7c NH |
1684 | /* |
1685 | * This double-check of PageHWPoison is to avoid the race with | |
1686 | * memory_failure(). See also comment in __soft_offline_page(). | |
1687 | */ | |
1688 | lock_page(hpage); | |
0ebff32c | 1689 | if (PageHWPoison(hpage)) { |
af8fae7c | 1690 | unlock_page(hpage); |
665d9da7 | 1691 | put_hwpoison_page(hpage); |
0ebff32c | 1692 | pr_info("soft offline: %#lx hugepage already poisoned\n", pfn); |
af8fae7c | 1693 | return -EBUSY; |
0ebff32c | 1694 | } |
af8fae7c | 1695 | unlock_page(hpage); |
d950b958 | 1696 | |
bcc54222 | 1697 | ret = isolate_huge_page(hpage, &pagelist); |
03613808 WL |
1698 | /* |
1699 | * get_any_page() and isolate_huge_page() takes a refcount each, | |
1700 | * so need to drop one here. | |
1701 | */ | |
665d9da7 | 1702 | put_hwpoison_page(hpage); |
03613808 | 1703 | if (!ret) { |
bcc54222 NH |
1704 | pr_info("soft offline: %#lx hugepage failed to isolate\n", pfn); |
1705 | return -EBUSY; | |
1706 | } | |
1707 | ||
68711a74 | 1708 | ret = migrate_pages(&pagelist, new_page, NULL, MPOL_MF_MOVE_ALL, |
b8ec1cee | 1709 | MIGRATE_SYNC, MR_MEMORY_FAILURE); |
d950b958 | 1710 | if (ret) { |
b6b18aa8 | 1711 | pr_info("soft offline: %#lx: hugepage migration failed %d, type %lx (%pGp)\n", |
82a2481e | 1712 | pfn, ret, page->flags, &page->flags); |
30809f55 PA |
1713 | if (!list_empty(&pagelist)) |
1714 | putback_movable_pages(&pagelist); | |
b8ec1cee NH |
1715 | if (ret > 0) |
1716 | ret = -EIO; | |
af8fae7c | 1717 | } else { |
6bc9b564 NH |
1718 | /* |
1719 | * We set PG_hwpoison only when the migration source hugepage | |
1720 | * was successfully dissolved, because otherwise hwpoisoned | |
1721 | * hugepage remains on free hugepage list, then userspace will | |
1722 | * find it as SIGBUS by allocation failure. That's not expected | |
1723 | * in soft-offlining. | |
1724 | */ | |
1725 | ret = dissolve_free_huge_page(page); | |
1726 | if (!ret) { | |
1727 | if (set_hwpoison_free_buddy_page(page)) | |
1728 | num_poisoned_pages_inc(); | |
b38e5962 NH |
1729 | else |
1730 | ret = -EBUSY; | |
6bc9b564 | 1731 | } |
d950b958 | 1732 | } |
d950b958 NH |
1733 | return ret; |
1734 | } | |
1735 | ||
af8fae7c NH |
1736 | static int __soft_offline_page(struct page *page, int flags) |
1737 | { | |
1738 | int ret; | |
1739 | unsigned long pfn = page_to_pfn(page); | |
facb6011 | 1740 | |
facb6011 | 1741 | /* |
af8fae7c NH |
1742 | * Check PageHWPoison again inside page lock because PageHWPoison |
1743 | * is set by memory_failure() outside page lock. Note that | |
1744 | * memory_failure() also double-checks PageHWPoison inside page lock, | |
1745 | * so there's no race between soft_offline_page() and memory_failure(). | |
facb6011 | 1746 | */ |
0ebff32c XQ |
1747 | lock_page(page); |
1748 | wait_on_page_writeback(page); | |
af8fae7c NH |
1749 | if (PageHWPoison(page)) { |
1750 | unlock_page(page); | |
665d9da7 | 1751 | put_hwpoison_page(page); |
af8fae7c NH |
1752 | pr_info("soft offline: %#lx page already poisoned\n", pfn); |
1753 | return -EBUSY; | |
1754 | } | |
facb6011 AK |
1755 | /* |
1756 | * Try to invalidate first. This should work for | |
1757 | * non dirty unmapped page cache pages. | |
1758 | */ | |
1759 | ret = invalidate_inode_page(page); | |
1760 | unlock_page(page); | |
facb6011 | 1761 | /* |
facb6011 AK |
1762 | * RED-PEN would be better to keep it isolated here, but we |
1763 | * would need to fix isolation locking first. | |
1764 | */ | |
facb6011 | 1765 | if (ret == 1) { |
665d9da7 | 1766 | put_hwpoison_page(page); |
fb46e735 | 1767 | pr_info("soft_offline: %#lx: invalidated\n", pfn); |
af8fae7c | 1768 | SetPageHWPoison(page); |
8e30456b | 1769 | num_poisoned_pages_inc(); |
af8fae7c | 1770 | return 0; |
facb6011 AK |
1771 | } |
1772 | ||
1773 | /* | |
1774 | * Simple invalidation didn't work. | |
1775 | * Try to migrate to a new page instead. migrate.c | |
1776 | * handles a large number of cases for us. | |
1777 | */ | |
85fbe5d1 YX |
1778 | if (PageLRU(page)) |
1779 | ret = isolate_lru_page(page); | |
1780 | else | |
1781 | ret = isolate_movable_page(page, ISOLATE_UNEVICTABLE); | |
bd486285 KK |
1782 | /* |
1783 | * Drop page reference which is came from get_any_page() | |
1784 | * successful isolate_lru_page() already took another one. | |
1785 | */ | |
665d9da7 | 1786 | put_hwpoison_page(page); |
facb6011 AK |
1787 | if (!ret) { |
1788 | LIST_HEAD(pagelist); | |
85fbe5d1 YX |
1789 | /* |
1790 | * After isolated lru page, the PageLRU will be cleared, | |
1791 | * so use !__PageMovable instead for LRU page's mapping | |
1792 | * cannot have PAGE_MAPPING_MOVABLE. | |
1793 | */ | |
1794 | if (!__PageMovable(page)) | |
1795 | inc_node_page_state(page, NR_ISOLATED_ANON + | |
1796 | page_is_file_cache(page)); | |
facb6011 | 1797 | list_add(&page->lru, &pagelist); |
68711a74 | 1798 | ret = migrate_pages(&pagelist, new_page, NULL, MPOL_MF_MOVE_ALL, |
9c620e2b | 1799 | MIGRATE_SYNC, MR_MEMORY_FAILURE); |
facb6011 | 1800 | if (ret) { |
85fbe5d1 YX |
1801 | if (!list_empty(&pagelist)) |
1802 | putback_movable_pages(&pagelist); | |
59c82b70 | 1803 | |
82a2481e AK |
1804 | pr_info("soft offline: %#lx: migration failed %d, type %lx (%pGp)\n", |
1805 | pfn, ret, page->flags, &page->flags); | |
facb6011 AK |
1806 | if (ret > 0) |
1807 | ret = -EIO; | |
1808 | } | |
1809 | } else { | |
82a2481e AK |
1810 | pr_info("soft offline: %#lx: isolation failed: %d, page count %d, type %lx (%pGp)\n", |
1811 | pfn, ret, page_count(page), page->flags, &page->flags); | |
facb6011 | 1812 | } |
facb6011 AK |
1813 | return ret; |
1814 | } | |
86e05773 | 1815 | |
acc14dc4 NH |
1816 | static int soft_offline_in_use_page(struct page *page, int flags) |
1817 | { | |
1818 | int ret; | |
d4ae9916 | 1819 | int mt; |
acc14dc4 NH |
1820 | struct page *hpage = compound_head(page); |
1821 | ||
1822 | if (!PageHuge(page) && PageTransHuge(hpage)) { | |
46612b75 | 1823 | lock_page(page); |
1824 | if (!PageAnon(page) || unlikely(split_huge_page(page))) { | |
1825 | unlock_page(page); | |
1826 | if (!PageAnon(page)) | |
98fd1ef4 NH |
1827 | pr_info("soft offline: %#lx: non anonymous thp\n", page_to_pfn(page)); |
1828 | else | |
1829 | pr_info("soft offline: %#lx: thp split failed\n", page_to_pfn(page)); | |
46612b75 | 1830 | put_hwpoison_page(page); |
acc14dc4 NH |
1831 | return -EBUSY; |
1832 | } | |
46612b75 | 1833 | unlock_page(page); |
acc14dc4 NH |
1834 | } |
1835 | ||
d4ae9916 NH |
1836 | /* |
1837 | * Setting MIGRATE_ISOLATE here ensures that the page will be linked | |
1838 | * to free list immediately (not via pcplist) when released after | |
1839 | * successful page migration. Otherwise we can't guarantee that the | |
1840 | * page is really free after put_page() returns, so | |
1841 | * set_hwpoison_free_buddy_page() highly likely fails. | |
1842 | */ | |
1843 | mt = get_pageblock_migratetype(page); | |
1844 | set_pageblock_migratetype(page, MIGRATE_ISOLATE); | |
acc14dc4 NH |
1845 | if (PageHuge(page)) |
1846 | ret = soft_offline_huge_page(page, flags); | |
1847 | else | |
1848 | ret = __soft_offline_page(page, flags); | |
d4ae9916 | 1849 | set_pageblock_migratetype(page, mt); |
acc14dc4 NH |
1850 | return ret; |
1851 | } | |
1852 | ||
d4ae9916 | 1853 | static int soft_offline_free_page(struct page *page) |
acc14dc4 | 1854 | { |
faf53def | 1855 | int rc = dissolve_free_huge_page(page); |
acc14dc4 | 1856 | |
d4ae9916 NH |
1857 | if (!rc) { |
1858 | if (set_hwpoison_free_buddy_page(page)) | |
1859 | num_poisoned_pages_inc(); | |
1860 | else | |
1861 | rc = -EBUSY; | |
1862 | } | |
1863 | return rc; | |
acc14dc4 NH |
1864 | } |
1865 | ||
86e05773 WL |
1866 | /** |
1867 | * soft_offline_page - Soft offline a page. | |
1868 | * @page: page to offline | |
1869 | * @flags: flags. Same as memory_failure(). | |
1870 | * | |
1871 | * Returns 0 on success, otherwise negated errno. | |
1872 | * | |
1873 | * Soft offline a page, by migration or invalidation, | |
1874 | * without killing anything. This is for the case when | |
1875 | * a page is not corrupted yet (so it's still valid to access), | |
1876 | * but has had a number of corrected errors and is better taken | |
1877 | * out. | |
1878 | * | |
1879 | * The actual policy on when to do that is maintained by | |
1880 | * user space. | |
1881 | * | |
1882 | * This should never impact any application or cause data loss, | |
1883 | * however it might take some time. | |
1884 | * | |
1885 | * This is not a 100% solution for all memory, but tries to be | |
1886 | * ``good enough'' for the majority of memory. | |
1887 | */ | |
1888 | int soft_offline_page(struct page *page, int flags) | |
1889 | { | |
1890 | int ret; | |
1891 | unsigned long pfn = page_to_pfn(page); | |
86e05773 | 1892 | |
86a66810 DW |
1893 | if (is_zone_device_page(page)) { |
1894 | pr_debug_ratelimited("soft_offline: %#lx page is device page\n", | |
1895 | pfn); | |
1896 | if (flags & MF_COUNT_INCREASED) | |
1897 | put_page(page); | |
1898 | return -EIO; | |
1899 | } | |
1900 | ||
86e05773 WL |
1901 | if (PageHWPoison(page)) { |
1902 | pr_info("soft offline: %#lx page already poisoned\n", pfn); | |
1e0e635b | 1903 | if (flags & MF_COUNT_INCREASED) |
665d9da7 | 1904 | put_hwpoison_page(page); |
86e05773 WL |
1905 | return -EBUSY; |
1906 | } | |
86e05773 | 1907 | |
bfc8c901 | 1908 | get_online_mems(); |
86e05773 | 1909 | ret = get_any_page(page, pfn, flags); |
bfc8c901 | 1910 | put_online_mems(); |
4e41a30c | 1911 | |
acc14dc4 NH |
1912 | if (ret > 0) |
1913 | ret = soft_offline_in_use_page(page, flags); | |
1914 | else if (ret == 0) | |
d4ae9916 | 1915 | ret = soft_offline_free_page(page); |
4e41a30c | 1916 | |
86e05773 WL |
1917 | return ret; |
1918 | } |