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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 | */ |
96f96763 KW |
36 | |
37 | #define pr_fmt(fmt) "Memory failure: " fmt | |
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> |
96c84dde | 45 | #include <linux/dax.h> |
01e00f88 | 46 | #include <linux/ksm.h> |
6a46079c | 47 | #include <linux/rmap.h> |
b9e15baf | 48 | #include <linux/export.h> |
6a46079c AK |
49 | #include <linux/pagemap.h> |
50 | #include <linux/swap.h> | |
51 | #include <linux/backing-dev.h> | |
facb6011 | 52 | #include <linux/migrate.h> |
facb6011 | 53 | #include <linux/suspend.h> |
5a0e3ad6 | 54 | #include <linux/slab.h> |
bf998156 | 55 | #include <linux/swapops.h> |
7af446a8 | 56 | #include <linux/hugetlb.h> |
20d6c96b | 57 | #include <linux/memory_hotplug.h> |
5db8a73a | 58 | #include <linux/mm_inline.h> |
6100e34b | 59 | #include <linux/memremap.h> |
ea8f5fb8 | 60 | #include <linux/kfifo.h> |
a5f65109 | 61 | #include <linux/ratelimit.h> |
d4ae9916 | 62 | #include <linux/page-isolation.h> |
a3f5d80e | 63 | #include <linux/pagewalk.h> |
a7605426 | 64 | #include <linux/shmem_fs.h> |
014bb1de | 65 | #include "swap.h" |
6a46079c | 66 | #include "internal.h" |
97f0b134 | 67 | #include "ras/ras_event.h" |
6a46079c AK |
68 | |
69 | int sysctl_memory_failure_early_kill __read_mostly = 0; | |
70 | ||
71 | int sysctl_memory_failure_recovery __read_mostly = 1; | |
72 | ||
293c07e3 | 73 | atomic_long_t num_poisoned_pages __read_mostly = ATOMIC_LONG_INIT(0); |
6a46079c | 74 | |
67f22ba7 | 75 | static bool hw_memory_failure __read_mostly = false; |
76 | ||
510d25c9 NH |
77 | static bool __page_handle_poison(struct page *page) |
78 | { | |
f87060d3 | 79 | int ret; |
510d25c9 NH |
80 | |
81 | zone_pcp_disable(page_zone(page)); | |
82 | ret = dissolve_free_huge_page(page); | |
83 | if (!ret) | |
84 | ret = take_page_off_buddy(page); | |
85 | zone_pcp_enable(page_zone(page)); | |
86 | ||
f87060d3 | 87 | return ret > 0; |
510d25c9 NH |
88 | } |
89 | ||
6b9a217e | 90 | static bool page_handle_poison(struct page *page, bool hugepage_or_freepage, bool release) |
06be6ff3 | 91 | { |
6b9a217e OS |
92 | if (hugepage_or_freepage) { |
93 | /* | |
94 | * Doing this check for free pages is also fine since dissolve_free_huge_page | |
95 | * returns 0 for non-hugetlb pages as well. | |
96 | */ | |
510d25c9 | 97 | if (!__page_handle_poison(page)) |
6b9a217e OS |
98 | /* |
99 | * We could fail to take off the target page from buddy | |
f0953a1b | 100 | * for example due to racy page allocation, but that's |
6b9a217e OS |
101 | * acceptable because soft-offlined page is not broken |
102 | * and if someone really want to use it, they should | |
103 | * take it. | |
104 | */ | |
105 | return false; | |
106 | } | |
107 | ||
06be6ff3 | 108 | SetPageHWPoison(page); |
79f5f8fa OS |
109 | if (release) |
110 | put_page(page); | |
06be6ff3 OS |
111 | page_ref_inc(page); |
112 | num_poisoned_pages_inc(); | |
6b9a217e OS |
113 | |
114 | return true; | |
06be6ff3 OS |
115 | } |
116 | ||
27df5068 AK |
117 | #if defined(CONFIG_HWPOISON_INJECT) || defined(CONFIG_HWPOISON_INJECT_MODULE) |
118 | ||
1bfe5feb | 119 | u32 hwpoison_filter_enable = 0; |
7c116f2b WF |
120 | u32 hwpoison_filter_dev_major = ~0U; |
121 | u32 hwpoison_filter_dev_minor = ~0U; | |
478c5ffc WF |
122 | u64 hwpoison_filter_flags_mask; |
123 | u64 hwpoison_filter_flags_value; | |
1bfe5feb | 124 | EXPORT_SYMBOL_GPL(hwpoison_filter_enable); |
7c116f2b WF |
125 | EXPORT_SYMBOL_GPL(hwpoison_filter_dev_major); |
126 | EXPORT_SYMBOL_GPL(hwpoison_filter_dev_minor); | |
478c5ffc WF |
127 | EXPORT_SYMBOL_GPL(hwpoison_filter_flags_mask); |
128 | EXPORT_SYMBOL_GPL(hwpoison_filter_flags_value); | |
7c116f2b WF |
129 | |
130 | static int hwpoison_filter_dev(struct page *p) | |
131 | { | |
132 | struct address_space *mapping; | |
133 | dev_t dev; | |
134 | ||
135 | if (hwpoison_filter_dev_major == ~0U && | |
136 | hwpoison_filter_dev_minor == ~0U) | |
137 | return 0; | |
138 | ||
7c116f2b WF |
139 | mapping = page_mapping(p); |
140 | if (mapping == NULL || mapping->host == NULL) | |
141 | return -EINVAL; | |
142 | ||
143 | dev = mapping->host->i_sb->s_dev; | |
144 | if (hwpoison_filter_dev_major != ~0U && | |
145 | hwpoison_filter_dev_major != MAJOR(dev)) | |
146 | return -EINVAL; | |
147 | if (hwpoison_filter_dev_minor != ~0U && | |
148 | hwpoison_filter_dev_minor != MINOR(dev)) | |
149 | return -EINVAL; | |
150 | ||
151 | return 0; | |
152 | } | |
153 | ||
478c5ffc WF |
154 | static int hwpoison_filter_flags(struct page *p) |
155 | { | |
156 | if (!hwpoison_filter_flags_mask) | |
157 | return 0; | |
158 | ||
159 | if ((stable_page_flags(p) & hwpoison_filter_flags_mask) == | |
160 | hwpoison_filter_flags_value) | |
161 | return 0; | |
162 | else | |
163 | return -EINVAL; | |
164 | } | |
165 | ||
4fd466eb AK |
166 | /* |
167 | * This allows stress tests to limit test scope to a collection of tasks | |
168 | * by putting them under some memcg. This prevents killing unrelated/important | |
169 | * processes such as /sbin/init. Note that the target task may share clean | |
170 | * pages with init (eg. libc text), which is harmless. If the target task | |
171 | * share _dirty_ pages with another task B, the test scheme must make sure B | |
172 | * is also included in the memcg. At last, due to race conditions this filter | |
173 | * can only guarantee that the page either belongs to the memcg tasks, or is | |
174 | * a freed page. | |
175 | */ | |
94a59fb3 | 176 | #ifdef CONFIG_MEMCG |
4fd466eb AK |
177 | u64 hwpoison_filter_memcg; |
178 | EXPORT_SYMBOL_GPL(hwpoison_filter_memcg); | |
179 | static int hwpoison_filter_task(struct page *p) | |
180 | { | |
4fd466eb AK |
181 | if (!hwpoison_filter_memcg) |
182 | return 0; | |
183 | ||
94a59fb3 | 184 | if (page_cgroup_ino(p) != hwpoison_filter_memcg) |
4fd466eb AK |
185 | return -EINVAL; |
186 | ||
187 | return 0; | |
188 | } | |
189 | #else | |
190 | static int hwpoison_filter_task(struct page *p) { return 0; } | |
191 | #endif | |
192 | ||
7c116f2b WF |
193 | int hwpoison_filter(struct page *p) |
194 | { | |
1bfe5feb HL |
195 | if (!hwpoison_filter_enable) |
196 | return 0; | |
197 | ||
7c116f2b WF |
198 | if (hwpoison_filter_dev(p)) |
199 | return -EINVAL; | |
200 | ||
478c5ffc WF |
201 | if (hwpoison_filter_flags(p)) |
202 | return -EINVAL; | |
203 | ||
4fd466eb AK |
204 | if (hwpoison_filter_task(p)) |
205 | return -EINVAL; | |
206 | ||
7c116f2b WF |
207 | return 0; |
208 | } | |
27df5068 AK |
209 | #else |
210 | int hwpoison_filter(struct page *p) | |
211 | { | |
212 | return 0; | |
213 | } | |
214 | #endif | |
215 | ||
7c116f2b WF |
216 | EXPORT_SYMBOL_GPL(hwpoison_filter); |
217 | ||
ae1139ec DW |
218 | /* |
219 | * Kill all processes that have a poisoned page mapped and then isolate | |
220 | * the page. | |
221 | * | |
222 | * General strategy: | |
223 | * Find all processes having the page mapped and kill them. | |
224 | * But we keep a page reference around so that the page is not | |
225 | * actually freed yet. | |
226 | * Then stash the page away | |
227 | * | |
228 | * There's no convenient way to get back to mapped processes | |
229 | * from the VMAs. So do a brute-force search over all | |
230 | * running processes. | |
231 | * | |
232 | * Remember that machine checks are not common (or rather | |
233 | * if they are common you have other problems), so this shouldn't | |
234 | * be a performance issue. | |
235 | * | |
236 | * Also there are some races possible while we get from the | |
237 | * error detection to actually handle it. | |
238 | */ | |
239 | ||
240 | struct to_kill { | |
241 | struct list_head nd; | |
242 | struct task_struct *tsk; | |
243 | unsigned long addr; | |
244 | short size_shift; | |
ae1139ec DW |
245 | }; |
246 | ||
6a46079c | 247 | /* |
7329bbeb TL |
248 | * Send all the processes who have the page mapped a signal. |
249 | * ``action optional'' if they are not immediately affected by the error | |
250 | * ``action required'' if error happened in current execution context | |
6a46079c | 251 | */ |
ae1139ec | 252 | static int kill_proc(struct to_kill *tk, unsigned long pfn, int flags) |
6a46079c | 253 | { |
ae1139ec DW |
254 | struct task_struct *t = tk->tsk; |
255 | short addr_lsb = tk->size_shift; | |
872e9a20 | 256 | int ret = 0; |
6a46079c | 257 | |
96f96763 | 258 | pr_err("%#lx: Sending SIGBUS to %s:%d due to hardware memory corruption\n", |
872e9a20 | 259 | pfn, t->comm, t->pid); |
7329bbeb | 260 | |
49775047 ML |
261 | if ((flags & MF_ACTION_REQUIRED) && (t == current)) |
262 | ret = force_sig_mceerr(BUS_MCEERR_AR, | |
263 | (void __user *)tk->addr, addr_lsb); | |
264 | else | |
7329bbeb | 265 | /* |
49775047 ML |
266 | * Signal other processes sharing the page if they have |
267 | * PF_MCE_EARLY set. | |
7329bbeb TL |
268 | * Don't use force here, it's convenient if the signal |
269 | * can be temporarily blocked. | |
270 | * This could cause a loop when the user sets SIGBUS | |
271 | * to SIG_IGN, but hopefully no one will do that? | |
272 | */ | |
ae1139ec | 273 | ret = send_sig_mceerr(BUS_MCEERR_AO, (void __user *)tk->addr, |
c0f45555 | 274 | addr_lsb, t); /* synchronous? */ |
6a46079c | 275 | if (ret < 0) |
96f96763 | 276 | pr_info("Error sending signal to %s:%d: %d\n", |
1170532b | 277 | t->comm, t->pid, ret); |
6a46079c AK |
278 | return ret; |
279 | } | |
280 | ||
588f9ce6 | 281 | /* |
47e431f4 | 282 | * Unknown page type encountered. Try to check whether it can turn PageLRU by |
d0505e9f | 283 | * lru_add_drain_all. |
588f9ce6 | 284 | */ |
d0505e9f | 285 | void shake_page(struct page *p) |
588f9ce6 | 286 | { |
8bcb74de NH |
287 | if (PageHuge(p)) |
288 | return; | |
289 | ||
588f9ce6 AK |
290 | if (!PageSlab(p)) { |
291 | lru_add_drain_all(); | |
588f9ce6 AK |
292 | if (PageLRU(p) || is_free_buddy_page(p)) |
293 | return; | |
294 | } | |
facb6011 | 295 | |
588f9ce6 | 296 | /* |
d0505e9f YS |
297 | * TODO: Could shrink slab caches here if a lightweight range-based |
298 | * shrinker will be available. | |
588f9ce6 AK |
299 | */ |
300 | } | |
301 | EXPORT_SYMBOL_GPL(shake_page); | |
302 | ||
c36e2024 SR |
303 | static unsigned long dev_pagemap_mapping_shift(struct vm_area_struct *vma, |
304 | unsigned long address) | |
6100e34b | 305 | { |
5c91c0e7 | 306 | unsigned long ret = 0; |
6100e34b DW |
307 | pgd_t *pgd; |
308 | p4d_t *p4d; | |
309 | pud_t *pud; | |
310 | pmd_t *pmd; | |
311 | pte_t *pte; | |
312 | ||
a994402b | 313 | VM_BUG_ON_VMA(address == -EFAULT, vma); |
6100e34b DW |
314 | pgd = pgd_offset(vma->vm_mm, address); |
315 | if (!pgd_present(*pgd)) | |
316 | return 0; | |
317 | p4d = p4d_offset(pgd, address); | |
318 | if (!p4d_present(*p4d)) | |
319 | return 0; | |
320 | pud = pud_offset(p4d, address); | |
321 | if (!pud_present(*pud)) | |
322 | return 0; | |
323 | if (pud_devmap(*pud)) | |
324 | return PUD_SHIFT; | |
325 | pmd = pmd_offset(pud, address); | |
326 | if (!pmd_present(*pmd)) | |
327 | return 0; | |
328 | if (pmd_devmap(*pmd)) | |
329 | return PMD_SHIFT; | |
330 | pte = pte_offset_map(pmd, address); | |
5c91c0e7 QZ |
331 | if (pte_present(*pte) && pte_devmap(*pte)) |
332 | ret = PAGE_SHIFT; | |
333 | pte_unmap(pte); | |
334 | return ret; | |
6100e34b | 335 | } |
6a46079c AK |
336 | |
337 | /* | |
338 | * Failure handling: if we can't find or can't kill a process there's | |
339 | * not much we can do. We just print a message and ignore otherwise. | |
340 | */ | |
341 | ||
342 | /* | |
343 | * Schedule a process for later kill. | |
344 | * Uses GFP_ATOMIC allocations to avoid potential recursions in the VM. | |
c36e2024 SR |
345 | * |
346 | * Notice: @fsdax_pgoff is used only when @p is a fsdax page. | |
347 | * In other cases, such as anonymous and file-backend page, the address to be | |
348 | * killed can be caculated by @p itself. | |
6a46079c AK |
349 | */ |
350 | static void add_to_kill(struct task_struct *tsk, struct page *p, | |
c36e2024 SR |
351 | pgoff_t fsdax_pgoff, struct vm_area_struct *vma, |
352 | struct list_head *to_kill) | |
6a46079c AK |
353 | { |
354 | struct to_kill *tk; | |
355 | ||
996ff7a0 JC |
356 | tk = kmalloc(sizeof(struct to_kill), GFP_ATOMIC); |
357 | if (!tk) { | |
96f96763 | 358 | pr_err("Out of memory while machine check handling\n"); |
996ff7a0 | 359 | return; |
6a46079c | 360 | } |
996ff7a0 | 361 | |
6a46079c | 362 | tk->addr = page_address_in_vma(p, vma); |
c36e2024 SR |
363 | if (is_zone_device_page(p)) { |
364 | /* | |
365 | * Since page->mapping is not used for fsdax, we need | |
366 | * calculate the address based on the vma. | |
367 | */ | |
368 | if (p->pgmap->type == MEMORY_DEVICE_FS_DAX) | |
369 | tk->addr = vma_pgoff_address(fsdax_pgoff, 1, vma); | |
370 | tk->size_shift = dev_pagemap_mapping_shift(vma, tk->addr); | |
371 | } else | |
75068518 | 372 | tk->size_shift = page_shift(compound_head(p)); |
6a46079c AK |
373 | |
374 | /* | |
3d7fed4a JC |
375 | * Send SIGKILL if "tk->addr == -EFAULT". Also, as |
376 | * "tk->size_shift" is always non-zero for !is_zone_device_page(), | |
377 | * so "tk->size_shift == 0" effectively checks no mapping on | |
378 | * ZONE_DEVICE. Indeed, when a devdax page is mmapped N times | |
379 | * to a process' address space, it's possible not all N VMAs | |
380 | * contain mappings for the page, but at least one VMA does. | |
381 | * Only deliver SIGBUS with payload derived from the VMA that | |
382 | * has a mapping for the page. | |
6a46079c | 383 | */ |
3d7fed4a | 384 | if (tk->addr == -EFAULT) { |
96f96763 | 385 | pr_info("Unable to find user space address %lx in %s\n", |
6a46079c | 386 | page_to_pfn(p), tsk->comm); |
3d7fed4a JC |
387 | } else if (tk->size_shift == 0) { |
388 | kfree(tk); | |
389 | return; | |
6a46079c | 390 | } |
996ff7a0 | 391 | |
6a46079c AK |
392 | get_task_struct(tsk); |
393 | tk->tsk = tsk; | |
394 | list_add_tail(&tk->nd, to_kill); | |
395 | } | |
396 | ||
397 | /* | |
398 | * Kill the processes that have been collected earlier. | |
399 | * | |
a21c184f ML |
400 | * Only do anything when FORCEKILL is set, otherwise just free the |
401 | * list (this is used for clean pages which do not need killing) | |
6a46079c AK |
402 | * Also when FAIL is set do a force kill because something went |
403 | * wrong earlier. | |
404 | */ | |
ae1139ec DW |
405 | static void kill_procs(struct list_head *to_kill, int forcekill, bool fail, |
406 | unsigned long pfn, int flags) | |
6a46079c AK |
407 | { |
408 | struct to_kill *tk, *next; | |
409 | ||
410 | list_for_each_entry_safe (tk, next, to_kill, nd) { | |
6751ed65 | 411 | if (forcekill) { |
6a46079c | 412 | /* |
af901ca1 | 413 | * In case something went wrong with munmapping |
6a46079c AK |
414 | * make sure the process doesn't catch the |
415 | * signal and then access the memory. Just kill it. | |
6a46079c | 416 | */ |
3d7fed4a | 417 | if (fail || tk->addr == -EFAULT) { |
96f96763 | 418 | pr_err("%#lx: forcibly killing %s:%d because of failure to unmap corrupted page\n", |
1170532b | 419 | pfn, tk->tsk->comm, tk->tsk->pid); |
6376360e NH |
420 | do_send_sig_info(SIGKILL, SEND_SIG_PRIV, |
421 | tk->tsk, PIDTYPE_PID); | |
6a46079c AK |
422 | } |
423 | ||
424 | /* | |
425 | * In theory the process could have mapped | |
426 | * something else on the address in-between. We could | |
427 | * check for that, but we need to tell the | |
428 | * process anyways. | |
429 | */ | |
ae1139ec | 430 | else if (kill_proc(tk, pfn, flags) < 0) |
96f96763 | 431 | pr_err("%#lx: Cannot send advisory machine check signal to %s:%d\n", |
1170532b | 432 | pfn, tk->tsk->comm, tk->tsk->pid); |
6a46079c AK |
433 | } |
434 | put_task_struct(tk->tsk); | |
435 | kfree(tk); | |
436 | } | |
437 | } | |
438 | ||
3ba08129 NH |
439 | /* |
440 | * Find a dedicated thread which is supposed to handle SIGBUS(BUS_MCEERR_AO) | |
441 | * on behalf of the thread group. Return task_struct of the (first found) | |
442 | * dedicated thread if found, and return NULL otherwise. | |
443 | * | |
444 | * We already hold read_lock(&tasklist_lock) in the caller, so we don't | |
445 | * have to call rcu_read_lock/unlock() in this function. | |
446 | */ | |
447 | static struct task_struct *find_early_kill_thread(struct task_struct *tsk) | |
6a46079c | 448 | { |
3ba08129 NH |
449 | struct task_struct *t; |
450 | ||
4e018b45 NH |
451 | for_each_thread(tsk, t) { |
452 | if (t->flags & PF_MCE_PROCESS) { | |
453 | if (t->flags & PF_MCE_EARLY) | |
454 | return t; | |
455 | } else { | |
456 | if (sysctl_memory_failure_early_kill) | |
457 | return t; | |
458 | } | |
459 | } | |
3ba08129 NH |
460 | return NULL; |
461 | } | |
462 | ||
463 | /* | |
464 | * Determine whether a given process is "early kill" process which expects | |
465 | * to be signaled when some page under the process is hwpoisoned. | |
466 | * Return task_struct of the dedicated thread (main thread unless explicitly | |
30c9cf49 | 467 | * specified) if the process is "early kill" and otherwise returns NULL. |
03151c6e | 468 | * |
30c9cf49 AY |
469 | * Note that the above is true for Action Optional case. For Action Required |
470 | * case, it's only meaningful to the current thread which need to be signaled | |
471 | * with SIGBUS, this error is Action Optional for other non current | |
472 | * processes sharing the same error page,if the process is "early kill", the | |
473 | * task_struct of the dedicated thread will also be returned. | |
3ba08129 NH |
474 | */ |
475 | static struct task_struct *task_early_kill(struct task_struct *tsk, | |
476 | int force_early) | |
477 | { | |
6a46079c | 478 | if (!tsk->mm) |
3ba08129 | 479 | return NULL; |
30c9cf49 AY |
480 | /* |
481 | * Comparing ->mm here because current task might represent | |
482 | * a subthread, while tsk always points to the main thread. | |
483 | */ | |
484 | if (force_early && tsk->mm == current->mm) | |
485 | return current; | |
486 | ||
4e018b45 | 487 | return find_early_kill_thread(tsk); |
6a46079c AK |
488 | } |
489 | ||
490 | /* | |
491 | * Collect processes when the error hit an anonymous page. | |
492 | */ | |
493 | static void collect_procs_anon(struct page *page, struct list_head *to_kill, | |
996ff7a0 | 494 | int force_early) |
6a46079c | 495 | { |
9595d769 | 496 | struct folio *folio = page_folio(page); |
6a46079c AK |
497 | struct vm_area_struct *vma; |
498 | struct task_struct *tsk; | |
499 | struct anon_vma *av; | |
bf181b9f | 500 | pgoff_t pgoff; |
6a46079c | 501 | |
6d4675e6 | 502 | av = folio_lock_anon_vma_read(folio, NULL); |
6a46079c | 503 | if (av == NULL) /* Not actually mapped anymore */ |
9b679320 PZ |
504 | return; |
505 | ||
a0f7a756 | 506 | pgoff = page_to_pgoff(page); |
9b679320 | 507 | read_lock(&tasklist_lock); |
6a46079c | 508 | for_each_process (tsk) { |
5beb4930 | 509 | struct anon_vma_chain *vmac; |
3ba08129 | 510 | struct task_struct *t = task_early_kill(tsk, force_early); |
5beb4930 | 511 | |
3ba08129 | 512 | if (!t) |
6a46079c | 513 | continue; |
bf181b9f ML |
514 | anon_vma_interval_tree_foreach(vmac, &av->rb_root, |
515 | pgoff, pgoff) { | |
5beb4930 | 516 | vma = vmac->vma; |
6a46079c AK |
517 | if (!page_mapped_in_vma(page, vma)) |
518 | continue; | |
3ba08129 | 519 | if (vma->vm_mm == t->mm) |
c36e2024 | 520 | add_to_kill(t, page, 0, vma, to_kill); |
6a46079c AK |
521 | } |
522 | } | |
6a46079c | 523 | read_unlock(&tasklist_lock); |
4fc3f1d6 | 524 | page_unlock_anon_vma_read(av); |
6a46079c AK |
525 | } |
526 | ||
527 | /* | |
528 | * Collect processes when the error hit a file mapped page. | |
529 | */ | |
530 | static void collect_procs_file(struct page *page, struct list_head *to_kill, | |
996ff7a0 | 531 | int force_early) |
6a46079c AK |
532 | { |
533 | struct vm_area_struct *vma; | |
534 | struct task_struct *tsk; | |
6a46079c | 535 | struct address_space *mapping = page->mapping; |
c43bc03d | 536 | pgoff_t pgoff; |
6a46079c | 537 | |
d28eb9c8 | 538 | i_mmap_lock_read(mapping); |
9b679320 | 539 | read_lock(&tasklist_lock); |
c43bc03d | 540 | pgoff = page_to_pgoff(page); |
6a46079c | 541 | for_each_process(tsk) { |
3ba08129 | 542 | struct task_struct *t = task_early_kill(tsk, force_early); |
6a46079c | 543 | |
3ba08129 | 544 | if (!t) |
6a46079c | 545 | continue; |
6b2dbba8 | 546 | vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, |
6a46079c AK |
547 | pgoff) { |
548 | /* | |
549 | * Send early kill signal to tasks where a vma covers | |
550 | * the page but the corrupted page is not necessarily | |
551 | * mapped it in its pte. | |
552 | * Assume applications who requested early kill want | |
553 | * to be informed of all such data corruptions. | |
554 | */ | |
3ba08129 | 555 | if (vma->vm_mm == t->mm) |
c36e2024 | 556 | add_to_kill(t, page, 0, vma, to_kill); |
6a46079c AK |
557 | } |
558 | } | |
6a46079c | 559 | read_unlock(&tasklist_lock); |
d28eb9c8 | 560 | i_mmap_unlock_read(mapping); |
6a46079c AK |
561 | } |
562 | ||
c36e2024 SR |
563 | #ifdef CONFIG_FS_DAX |
564 | /* | |
565 | * Collect processes when the error hit a fsdax page. | |
566 | */ | |
567 | static void collect_procs_fsdax(struct page *page, | |
568 | struct address_space *mapping, pgoff_t pgoff, | |
569 | struct list_head *to_kill) | |
570 | { | |
571 | struct vm_area_struct *vma; | |
572 | struct task_struct *tsk; | |
573 | ||
574 | i_mmap_lock_read(mapping); | |
575 | read_lock(&tasklist_lock); | |
576 | for_each_process(tsk) { | |
577 | struct task_struct *t = task_early_kill(tsk, true); | |
578 | ||
579 | if (!t) | |
580 | continue; | |
581 | vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) { | |
582 | if (vma->vm_mm == t->mm) | |
583 | add_to_kill(t, page, pgoff, vma, to_kill); | |
584 | } | |
585 | } | |
586 | read_unlock(&tasklist_lock); | |
587 | i_mmap_unlock_read(mapping); | |
588 | } | |
589 | #endif /* CONFIG_FS_DAX */ | |
590 | ||
6a46079c AK |
591 | /* |
592 | * Collect the processes who have the corrupted page mapped to kill. | |
6a46079c | 593 | */ |
74614de1 TL |
594 | static void collect_procs(struct page *page, struct list_head *tokill, |
595 | int force_early) | |
6a46079c | 596 | { |
6a46079c AK |
597 | if (!page->mapping) |
598 | return; | |
599 | ||
6a46079c | 600 | if (PageAnon(page)) |
996ff7a0 | 601 | collect_procs_anon(page, tokill, force_early); |
6a46079c | 602 | else |
996ff7a0 | 603 | collect_procs_file(page, tokill, force_early); |
6a46079c AK |
604 | } |
605 | ||
a3f5d80e NH |
606 | struct hwp_walk { |
607 | struct to_kill tk; | |
608 | unsigned long pfn; | |
609 | int flags; | |
610 | }; | |
611 | ||
612 | static void set_to_kill(struct to_kill *tk, unsigned long addr, short shift) | |
613 | { | |
614 | tk->addr = addr; | |
615 | tk->size_shift = shift; | |
616 | } | |
617 | ||
618 | static int check_hwpoisoned_entry(pte_t pte, unsigned long addr, short shift, | |
619 | unsigned long poisoned_pfn, struct to_kill *tk) | |
620 | { | |
621 | unsigned long pfn = 0; | |
622 | ||
623 | if (pte_present(pte)) { | |
624 | pfn = pte_pfn(pte); | |
625 | } else { | |
626 | swp_entry_t swp = pte_to_swp_entry(pte); | |
627 | ||
628 | if (is_hwpoison_entry(swp)) | |
629 | pfn = hwpoison_entry_to_pfn(swp); | |
630 | } | |
631 | ||
632 | if (!pfn || pfn != poisoned_pfn) | |
633 | return 0; | |
634 | ||
635 | set_to_kill(tk, addr, shift); | |
636 | return 1; | |
637 | } | |
638 | ||
639 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE | |
640 | static int check_hwpoisoned_pmd_entry(pmd_t *pmdp, unsigned long addr, | |
641 | struct hwp_walk *hwp) | |
642 | { | |
643 | pmd_t pmd = *pmdp; | |
644 | unsigned long pfn; | |
645 | unsigned long hwpoison_vaddr; | |
646 | ||
647 | if (!pmd_present(pmd)) | |
648 | return 0; | |
649 | pfn = pmd_pfn(pmd); | |
650 | if (pfn <= hwp->pfn && hwp->pfn < pfn + HPAGE_PMD_NR) { | |
651 | hwpoison_vaddr = addr + ((hwp->pfn - pfn) << PAGE_SHIFT); | |
652 | set_to_kill(&hwp->tk, hwpoison_vaddr, PAGE_SHIFT); | |
653 | return 1; | |
654 | } | |
655 | return 0; | |
656 | } | |
657 | #else | |
658 | static int check_hwpoisoned_pmd_entry(pmd_t *pmdp, unsigned long addr, | |
659 | struct hwp_walk *hwp) | |
660 | { | |
661 | return 0; | |
662 | } | |
663 | #endif | |
664 | ||
665 | static int hwpoison_pte_range(pmd_t *pmdp, unsigned long addr, | |
666 | unsigned long end, struct mm_walk *walk) | |
667 | { | |
f142e707 | 668 | struct hwp_walk *hwp = walk->private; |
a3f5d80e | 669 | int ret = 0; |
ea3732f7 | 670 | pte_t *ptep, *mapped_pte; |
a3f5d80e NH |
671 | spinlock_t *ptl; |
672 | ||
673 | ptl = pmd_trans_huge_lock(pmdp, walk->vma); | |
674 | if (ptl) { | |
675 | ret = check_hwpoisoned_pmd_entry(pmdp, addr, hwp); | |
676 | spin_unlock(ptl); | |
677 | goto out; | |
678 | } | |
679 | ||
680 | if (pmd_trans_unstable(pmdp)) | |
681 | goto out; | |
682 | ||
ea3732f7 ML |
683 | mapped_pte = ptep = pte_offset_map_lock(walk->vma->vm_mm, pmdp, |
684 | addr, &ptl); | |
a3f5d80e NH |
685 | for (; addr != end; ptep++, addr += PAGE_SIZE) { |
686 | ret = check_hwpoisoned_entry(*ptep, addr, PAGE_SHIFT, | |
687 | hwp->pfn, &hwp->tk); | |
688 | if (ret == 1) | |
689 | break; | |
690 | } | |
ea3732f7 | 691 | pte_unmap_unlock(mapped_pte, ptl); |
a3f5d80e NH |
692 | out: |
693 | cond_resched(); | |
694 | return ret; | |
695 | } | |
696 | ||
697 | #ifdef CONFIG_HUGETLB_PAGE | |
698 | static int hwpoison_hugetlb_range(pte_t *ptep, unsigned long hmask, | |
699 | unsigned long addr, unsigned long end, | |
700 | struct mm_walk *walk) | |
701 | { | |
f142e707 | 702 | struct hwp_walk *hwp = walk->private; |
a3f5d80e NH |
703 | pte_t pte = huge_ptep_get(ptep); |
704 | struct hstate *h = hstate_vma(walk->vma); | |
705 | ||
706 | return check_hwpoisoned_entry(pte, addr, huge_page_shift(h), | |
707 | hwp->pfn, &hwp->tk); | |
708 | } | |
709 | #else | |
710 | #define hwpoison_hugetlb_range NULL | |
711 | #endif | |
712 | ||
ba9eb3ce | 713 | static const struct mm_walk_ops hwp_walk_ops = { |
a3f5d80e NH |
714 | .pmd_entry = hwpoison_pte_range, |
715 | .hugetlb_entry = hwpoison_hugetlb_range, | |
716 | }; | |
717 | ||
718 | /* | |
719 | * Sends SIGBUS to the current process with error info. | |
720 | * | |
721 | * This function is intended to handle "Action Required" MCEs on already | |
722 | * hardware poisoned pages. They could happen, for example, when | |
723 | * memory_failure() failed to unmap the error page at the first call, or | |
724 | * when multiple local machine checks happened on different CPUs. | |
725 | * | |
726 | * MCE handler currently has no easy access to the error virtual address, | |
727 | * so this function walks page table to find it. The returned virtual address | |
728 | * is proper in most cases, but it could be wrong when the application | |
729 | * process has multiple entries mapping the error page. | |
730 | */ | |
731 | static int kill_accessing_process(struct task_struct *p, unsigned long pfn, | |
732 | int flags) | |
733 | { | |
734 | int ret; | |
735 | struct hwp_walk priv = { | |
736 | .pfn = pfn, | |
737 | }; | |
738 | priv.tk.tsk = p; | |
739 | ||
740 | mmap_read_lock(p->mm); | |
741 | ret = walk_page_range(p->mm, 0, TASK_SIZE, &hwp_walk_ops, | |
742 | (void *)&priv); | |
743 | if (ret == 1 && priv.tk.addr) | |
744 | kill_proc(&priv.tk, pfn, flags); | |
046545a6 NH |
745 | else |
746 | ret = 0; | |
a3f5d80e | 747 | mmap_read_unlock(p->mm); |
046545a6 | 748 | return ret > 0 ? -EHWPOISON : -EFAULT; |
a3f5d80e NH |
749 | } |
750 | ||
6a46079c | 751 | static const char *action_name[] = { |
cc637b17 XX |
752 | [MF_IGNORED] = "Ignored", |
753 | [MF_FAILED] = "Failed", | |
754 | [MF_DELAYED] = "Delayed", | |
755 | [MF_RECOVERED] = "Recovered", | |
64d37a2b NH |
756 | }; |
757 | ||
758 | static const char * const action_page_types[] = { | |
cc637b17 XX |
759 | [MF_MSG_KERNEL] = "reserved kernel page", |
760 | [MF_MSG_KERNEL_HIGH_ORDER] = "high-order kernel page", | |
761 | [MF_MSG_SLAB] = "kernel slab page", | |
762 | [MF_MSG_DIFFERENT_COMPOUND] = "different compound page after locking", | |
cc637b17 XX |
763 | [MF_MSG_HUGE] = "huge page", |
764 | [MF_MSG_FREE_HUGE] = "free huge page", | |
31286a84 | 765 | [MF_MSG_NON_PMD_HUGE] = "non-pmd-sized huge page", |
cc637b17 XX |
766 | [MF_MSG_UNMAP_FAILED] = "unmapping failed page", |
767 | [MF_MSG_DIRTY_SWAPCACHE] = "dirty swapcache page", | |
768 | [MF_MSG_CLEAN_SWAPCACHE] = "clean swapcache page", | |
769 | [MF_MSG_DIRTY_MLOCKED_LRU] = "dirty mlocked LRU page", | |
770 | [MF_MSG_CLEAN_MLOCKED_LRU] = "clean mlocked LRU page", | |
771 | [MF_MSG_DIRTY_UNEVICTABLE_LRU] = "dirty unevictable LRU page", | |
772 | [MF_MSG_CLEAN_UNEVICTABLE_LRU] = "clean unevictable LRU page", | |
773 | [MF_MSG_DIRTY_LRU] = "dirty LRU page", | |
774 | [MF_MSG_CLEAN_LRU] = "clean LRU page", | |
775 | [MF_MSG_TRUNCATED_LRU] = "already truncated LRU page", | |
776 | [MF_MSG_BUDDY] = "free buddy page", | |
6100e34b | 777 | [MF_MSG_DAX] = "dax page", |
5d1fd5dc | 778 | [MF_MSG_UNSPLIT_THP] = "unsplit thp", |
cc637b17 | 779 | [MF_MSG_UNKNOWN] = "unknown page", |
64d37a2b NH |
780 | }; |
781 | ||
dc2a1cbf WF |
782 | /* |
783 | * XXX: It is possible that a page is isolated from LRU cache, | |
784 | * and then kept in swap cache or failed to remove from page cache. | |
785 | * The page count will stop it from being freed by unpoison. | |
786 | * Stress tests should be aware of this memory leak problem. | |
787 | */ | |
788 | static int delete_from_lru_cache(struct page *p) | |
789 | { | |
790 | if (!isolate_lru_page(p)) { | |
791 | /* | |
792 | * Clear sensible page flags, so that the buddy system won't | |
793 | * complain when the page is unpoison-and-freed. | |
794 | */ | |
795 | ClearPageActive(p); | |
796 | ClearPageUnevictable(p); | |
18365225 MH |
797 | |
798 | /* | |
799 | * Poisoned page might never drop its ref count to 0 so we have | |
800 | * to uncharge it manually from its memcg. | |
801 | */ | |
bbc6b703 | 802 | mem_cgroup_uncharge(page_folio(p)); |
18365225 | 803 | |
dc2a1cbf WF |
804 | /* |
805 | * drop the page count elevated by isolate_lru_page() | |
806 | */ | |
09cbfeaf | 807 | put_page(p); |
dc2a1cbf WF |
808 | return 0; |
809 | } | |
810 | return -EIO; | |
811 | } | |
812 | ||
78bb9203 NH |
813 | static int truncate_error_page(struct page *p, unsigned long pfn, |
814 | struct address_space *mapping) | |
815 | { | |
816 | int ret = MF_FAILED; | |
817 | ||
818 | if (mapping->a_ops->error_remove_page) { | |
819 | int err = mapping->a_ops->error_remove_page(mapping, p); | |
820 | ||
821 | if (err != 0) { | |
96f96763 | 822 | pr_info("%#lx: Failed to punch page: %d\n", pfn, err); |
78bb9203 NH |
823 | } else if (page_has_private(p) && |
824 | !try_to_release_page(p, GFP_NOIO)) { | |
96f96763 | 825 | pr_info("%#lx: failed to release buffers\n", pfn); |
78bb9203 NH |
826 | } else { |
827 | ret = MF_RECOVERED; | |
828 | } | |
829 | } else { | |
830 | /* | |
831 | * If the file system doesn't support it just invalidate | |
832 | * This fails on dirty or anything with private pages | |
833 | */ | |
834 | if (invalidate_inode_page(p)) | |
835 | ret = MF_RECOVERED; | |
836 | else | |
96f96763 | 837 | pr_info("%#lx: Failed to invalidate\n", pfn); |
78bb9203 NH |
838 | } |
839 | ||
840 | return ret; | |
841 | } | |
842 | ||
dd0f230a YS |
843 | struct page_state { |
844 | unsigned long mask; | |
845 | unsigned long res; | |
846 | enum mf_action_page_type type; | |
847 | ||
848 | /* Callback ->action() has to unlock the relevant page inside it. */ | |
849 | int (*action)(struct page_state *ps, struct page *p); | |
850 | }; | |
851 | ||
852 | /* | |
853 | * Return true if page is still referenced by others, otherwise return | |
854 | * false. | |
855 | * | |
856 | * The extra_pins is true when one extra refcount is expected. | |
857 | */ | |
858 | static bool has_extra_refcount(struct page_state *ps, struct page *p, | |
859 | bool extra_pins) | |
860 | { | |
861 | int count = page_count(p) - 1; | |
862 | ||
863 | if (extra_pins) | |
864 | count -= 1; | |
865 | ||
866 | if (count > 0) { | |
96f96763 | 867 | pr_err("%#lx: %s still referenced by %d users\n", |
dd0f230a YS |
868 | page_to_pfn(p), action_page_types[ps->type], count); |
869 | return true; | |
870 | } | |
871 | ||
872 | return false; | |
873 | } | |
874 | ||
6a46079c AK |
875 | /* |
876 | * Error hit kernel page. | |
877 | * Do nothing, try to be lucky and not touch this instead. For a few cases we | |
878 | * could be more sophisticated. | |
879 | */ | |
dd0f230a | 880 | static int me_kernel(struct page_state *ps, struct page *p) |
6a46079c | 881 | { |
ea6d0630 | 882 | unlock_page(p); |
cc637b17 | 883 | return MF_IGNORED; |
6a46079c AK |
884 | } |
885 | ||
886 | /* | |
887 | * Page in unknown state. Do nothing. | |
888 | */ | |
dd0f230a | 889 | static int me_unknown(struct page_state *ps, struct page *p) |
6a46079c | 890 | { |
96f96763 | 891 | pr_err("%#lx: Unknown page state\n", page_to_pfn(p)); |
ea6d0630 | 892 | unlock_page(p); |
cc637b17 | 893 | return MF_FAILED; |
6a46079c AK |
894 | } |
895 | ||
6a46079c AK |
896 | /* |
897 | * Clean (or cleaned) page cache page. | |
898 | */ | |
dd0f230a | 899 | static int me_pagecache_clean(struct page_state *ps, struct page *p) |
6a46079c | 900 | { |
ea6d0630 | 901 | int ret; |
6a46079c | 902 | struct address_space *mapping; |
a7605426 | 903 | bool extra_pins; |
6a46079c | 904 | |
dc2a1cbf WF |
905 | delete_from_lru_cache(p); |
906 | ||
6a46079c AK |
907 | /* |
908 | * For anonymous pages we're done the only reference left | |
909 | * should be the one m_f() holds. | |
910 | */ | |
ea6d0630 NH |
911 | if (PageAnon(p)) { |
912 | ret = MF_RECOVERED; | |
913 | goto out; | |
914 | } | |
6a46079c AK |
915 | |
916 | /* | |
917 | * Now truncate the page in the page cache. This is really | |
918 | * more like a "temporary hole punch" | |
919 | * Don't do this for block devices when someone else | |
920 | * has a reference, because it could be file system metadata | |
921 | * and that's not safe to truncate. | |
922 | */ | |
923 | mapping = page_mapping(p); | |
924 | if (!mapping) { | |
925 | /* | |
926 | * Page has been teared down in the meanwhile | |
927 | */ | |
ea6d0630 NH |
928 | ret = MF_FAILED; |
929 | goto out; | |
6a46079c AK |
930 | } |
931 | ||
a7605426 YS |
932 | /* |
933 | * The shmem page is kept in page cache instead of truncating | |
934 | * so is expected to have an extra refcount after error-handling. | |
935 | */ | |
936 | extra_pins = shmem_mapping(mapping); | |
937 | ||
6a46079c AK |
938 | /* |
939 | * Truncation is a bit tricky. Enable it per file system for now. | |
940 | * | |
9608703e | 941 | * Open: to take i_rwsem or not for this? Right now we don't. |
6a46079c | 942 | */ |
dd0f230a | 943 | ret = truncate_error_page(p, page_to_pfn(p), mapping); |
a7605426 YS |
944 | if (has_extra_refcount(ps, p, extra_pins)) |
945 | ret = MF_FAILED; | |
946 | ||
ea6d0630 NH |
947 | out: |
948 | unlock_page(p); | |
dd0f230a | 949 | |
ea6d0630 | 950 | return ret; |
6a46079c AK |
951 | } |
952 | ||
953 | /* | |
549543df | 954 | * Dirty pagecache page |
6a46079c AK |
955 | * Issues: when the error hit a hole page the error is not properly |
956 | * propagated. | |
957 | */ | |
dd0f230a | 958 | static int me_pagecache_dirty(struct page_state *ps, struct page *p) |
6a46079c AK |
959 | { |
960 | struct address_space *mapping = page_mapping(p); | |
961 | ||
962 | SetPageError(p); | |
963 | /* TBD: print more information about the file. */ | |
964 | if (mapping) { | |
965 | /* | |
966 | * IO error will be reported by write(), fsync(), etc. | |
967 | * who check the mapping. | |
968 | * This way the application knows that something went | |
969 | * wrong with its dirty file data. | |
970 | * | |
971 | * There's one open issue: | |
972 | * | |
973 | * The EIO will be only reported on the next IO | |
974 | * operation and then cleared through the IO map. | |
975 | * Normally Linux has two mechanisms to pass IO error | |
976 | * first through the AS_EIO flag in the address space | |
977 | * and then through the PageError flag in the page. | |
978 | * Since we drop pages on memory failure handling the | |
979 | * only mechanism open to use is through AS_AIO. | |
980 | * | |
981 | * This has the disadvantage that it gets cleared on | |
982 | * the first operation that returns an error, while | |
983 | * the PageError bit is more sticky and only cleared | |
984 | * when the page is reread or dropped. If an | |
985 | * application assumes it will always get error on | |
986 | * fsync, but does other operations on the fd before | |
25985edc | 987 | * and the page is dropped between then the error |
6a46079c AK |
988 | * will not be properly reported. |
989 | * | |
990 | * This can already happen even without hwpoisoned | |
991 | * pages: first on metadata IO errors (which only | |
992 | * report through AS_EIO) or when the page is dropped | |
993 | * at the wrong time. | |
994 | * | |
995 | * So right now we assume that the application DTRT on | |
996 | * the first EIO, but we're not worse than other parts | |
997 | * of the kernel. | |
998 | */ | |
af21bfaf | 999 | mapping_set_error(mapping, -EIO); |
6a46079c AK |
1000 | } |
1001 | ||
dd0f230a | 1002 | return me_pagecache_clean(ps, p); |
6a46079c AK |
1003 | } |
1004 | ||
1005 | /* | |
1006 | * Clean and dirty swap cache. | |
1007 | * | |
1008 | * Dirty swap cache page is tricky to handle. The page could live both in page | |
1009 | * cache and swap cache(ie. page is freshly swapped in). So it could be | |
1010 | * referenced concurrently by 2 types of PTEs: | |
1011 | * normal PTEs and swap PTEs. We try to handle them consistently by calling | |
1012 | * try_to_unmap(TTU_IGNORE_HWPOISON) to convert the normal PTEs to swap PTEs, | |
1013 | * and then | |
1014 | * - clear dirty bit to prevent IO | |
1015 | * - remove from LRU | |
1016 | * - but keep in the swap cache, so that when we return to it on | |
1017 | * a later page fault, we know the application is accessing | |
1018 | * corrupted data and shall be killed (we installed simple | |
1019 | * interception code in do_swap_page to catch it). | |
1020 | * | |
1021 | * Clean swap cache pages can be directly isolated. A later page fault will | |
1022 | * bring in the known good data from disk. | |
1023 | */ | |
dd0f230a | 1024 | static int me_swapcache_dirty(struct page_state *ps, struct page *p) |
6a46079c | 1025 | { |
ea6d0630 | 1026 | int ret; |
dd0f230a | 1027 | bool extra_pins = false; |
ea6d0630 | 1028 | |
6a46079c AK |
1029 | ClearPageDirty(p); |
1030 | /* Trigger EIO in shmem: */ | |
1031 | ClearPageUptodate(p); | |
1032 | ||
ea6d0630 NH |
1033 | ret = delete_from_lru_cache(p) ? MF_FAILED : MF_DELAYED; |
1034 | unlock_page(p); | |
dd0f230a YS |
1035 | |
1036 | if (ret == MF_DELAYED) | |
1037 | extra_pins = true; | |
1038 | ||
1039 | if (has_extra_refcount(ps, p, extra_pins)) | |
1040 | ret = MF_FAILED; | |
1041 | ||
ea6d0630 | 1042 | return ret; |
6a46079c AK |
1043 | } |
1044 | ||
dd0f230a | 1045 | static int me_swapcache_clean(struct page_state *ps, struct page *p) |
6a46079c | 1046 | { |
75fa68a5 | 1047 | struct folio *folio = page_folio(p); |
ea6d0630 NH |
1048 | int ret; |
1049 | ||
75fa68a5 | 1050 | delete_from_swap_cache(folio); |
e43c3afb | 1051 | |
ea6d0630 | 1052 | ret = delete_from_lru_cache(p) ? MF_FAILED : MF_RECOVERED; |
75fa68a5 | 1053 | folio_unlock(folio); |
dd0f230a YS |
1054 | |
1055 | if (has_extra_refcount(ps, p, false)) | |
1056 | ret = MF_FAILED; | |
1057 | ||
ea6d0630 | 1058 | return ret; |
6a46079c AK |
1059 | } |
1060 | ||
1061 | /* | |
1062 | * Huge pages. Needs work. | |
1063 | * Issues: | |
93f70f90 NH |
1064 | * - Error on hugepage is contained in hugepage unit (not in raw page unit.) |
1065 | * To narrow down kill region to one page, we need to break up pmd. | |
6a46079c | 1066 | */ |
dd0f230a | 1067 | static int me_huge_page(struct page_state *ps, struct page *p) |
6a46079c | 1068 | { |
a8b2c2ce | 1069 | int res; |
93f70f90 | 1070 | struct page *hpage = compound_head(p); |
78bb9203 | 1071 | struct address_space *mapping; |
2491ffee NH |
1072 | |
1073 | if (!PageHuge(hpage)) | |
1074 | return MF_DELAYED; | |
1075 | ||
78bb9203 NH |
1076 | mapping = page_mapping(hpage); |
1077 | if (mapping) { | |
dd0f230a | 1078 | res = truncate_error_page(hpage, page_to_pfn(p), mapping); |
ea6d0630 | 1079 | unlock_page(hpage); |
78bb9203 | 1080 | } else { |
a8b2c2ce | 1081 | res = MF_FAILED; |
78bb9203 NH |
1082 | unlock_page(hpage); |
1083 | /* | |
ef526b17 ML |
1084 | * migration entry prevents later access on error hugepage, |
1085 | * so we can free and dissolve it into buddy to save healthy | |
1086 | * subpages. | |
78bb9203 | 1087 | */ |
ef526b17 | 1088 | put_page(hpage); |
510d25c9 | 1089 | if (__page_handle_poison(p)) { |
a8b2c2ce OS |
1090 | page_ref_inc(p); |
1091 | res = MF_RECOVERED; | |
1092 | } | |
93f70f90 | 1093 | } |
78bb9203 | 1094 | |
dd0f230a YS |
1095 | if (has_extra_refcount(ps, p, false)) |
1096 | res = MF_FAILED; | |
1097 | ||
78bb9203 | 1098 | return res; |
6a46079c AK |
1099 | } |
1100 | ||
1101 | /* | |
1102 | * Various page states we can handle. | |
1103 | * | |
1104 | * A page state is defined by its current page->flags bits. | |
1105 | * The table matches them in order and calls the right handler. | |
1106 | * | |
1107 | * This is quite tricky because we can access page at any time | |
25985edc | 1108 | * in its live cycle, so all accesses have to be extremely careful. |
6a46079c AK |
1109 | * |
1110 | * This is not complete. More states could be added. | |
1111 | * For any missing state don't attempt recovery. | |
1112 | */ | |
1113 | ||
1114 | #define dirty (1UL << PG_dirty) | |
6326fec1 | 1115 | #define sc ((1UL << PG_swapcache) | (1UL << PG_swapbacked)) |
6a46079c AK |
1116 | #define unevict (1UL << PG_unevictable) |
1117 | #define mlock (1UL << PG_mlocked) | |
6a46079c | 1118 | #define lru (1UL << PG_lru) |
6a46079c | 1119 | #define head (1UL << PG_head) |
6a46079c | 1120 | #define slab (1UL << PG_slab) |
6a46079c AK |
1121 | #define reserved (1UL << PG_reserved) |
1122 | ||
dd0f230a | 1123 | static struct page_state error_states[] = { |
cc637b17 | 1124 | { reserved, reserved, MF_MSG_KERNEL, me_kernel }, |
95d01fc6 WF |
1125 | /* |
1126 | * free pages are specially detected outside this table: | |
1127 | * PG_buddy pages only make a small fraction of all free pages. | |
1128 | */ | |
6a46079c AK |
1129 | |
1130 | /* | |
1131 | * Could in theory check if slab page is free or if we can drop | |
1132 | * currently unused objects without touching them. But just | |
1133 | * treat it as standard kernel for now. | |
1134 | */ | |
cc637b17 | 1135 | { slab, slab, MF_MSG_SLAB, me_kernel }, |
6a46079c | 1136 | |
cc637b17 | 1137 | { head, head, MF_MSG_HUGE, me_huge_page }, |
6a46079c | 1138 | |
cc637b17 XX |
1139 | { sc|dirty, sc|dirty, MF_MSG_DIRTY_SWAPCACHE, me_swapcache_dirty }, |
1140 | { sc|dirty, sc, MF_MSG_CLEAN_SWAPCACHE, me_swapcache_clean }, | |
6a46079c | 1141 | |
cc637b17 XX |
1142 | { mlock|dirty, mlock|dirty, MF_MSG_DIRTY_MLOCKED_LRU, me_pagecache_dirty }, |
1143 | { mlock|dirty, mlock, MF_MSG_CLEAN_MLOCKED_LRU, me_pagecache_clean }, | |
6a46079c | 1144 | |
cc637b17 XX |
1145 | { unevict|dirty, unevict|dirty, MF_MSG_DIRTY_UNEVICTABLE_LRU, me_pagecache_dirty }, |
1146 | { unevict|dirty, unevict, MF_MSG_CLEAN_UNEVICTABLE_LRU, me_pagecache_clean }, | |
5f4b9fc5 | 1147 | |
cc637b17 XX |
1148 | { lru|dirty, lru|dirty, MF_MSG_DIRTY_LRU, me_pagecache_dirty }, |
1149 | { lru|dirty, lru, MF_MSG_CLEAN_LRU, me_pagecache_clean }, | |
6a46079c AK |
1150 | |
1151 | /* | |
1152 | * Catchall entry: must be at end. | |
1153 | */ | |
cc637b17 | 1154 | { 0, 0, MF_MSG_UNKNOWN, me_unknown }, |
6a46079c AK |
1155 | }; |
1156 | ||
2326c467 AK |
1157 | #undef dirty |
1158 | #undef sc | |
1159 | #undef unevict | |
1160 | #undef mlock | |
2326c467 | 1161 | #undef lru |
2326c467 | 1162 | #undef head |
2326c467 AK |
1163 | #undef slab |
1164 | #undef reserved | |
1165 | ||
ff604cf6 NH |
1166 | /* |
1167 | * "Dirty/Clean" indication is not 100% accurate due to the possibility of | |
1168 | * setting PG_dirty outside page lock. See also comment above set_page_dirty(). | |
1169 | */ | |
cc3e2af4 XX |
1170 | static void action_result(unsigned long pfn, enum mf_action_page_type type, |
1171 | enum mf_result result) | |
6a46079c | 1172 | { |
97f0b134 XX |
1173 | trace_memory_failure_event(pfn, type, result); |
1174 | ||
e240ac52 | 1175 | num_poisoned_pages_inc(); |
96f96763 | 1176 | pr_err("%#lx: recovery action for %s: %s\n", |
64d37a2b | 1177 | pfn, action_page_types[type], action_name[result]); |
6a46079c AK |
1178 | } |
1179 | ||
1180 | static int page_action(struct page_state *ps, struct page *p, | |
bd1ce5f9 | 1181 | unsigned long pfn) |
6a46079c AK |
1182 | { |
1183 | int result; | |
1184 | ||
ea6d0630 | 1185 | /* page p should be unlocked after returning from ps->action(). */ |
dd0f230a | 1186 | result = ps->action(ps, p); |
7456b040 | 1187 | |
64d37a2b | 1188 | action_result(pfn, ps->type, result); |
6a46079c AK |
1189 | |
1190 | /* Could do more checks here if page looks ok */ | |
1191 | /* | |
1192 | * Could adjust zone counters here to correct for the missing page. | |
1193 | */ | |
1194 | ||
cc637b17 | 1195 | return (result == MF_RECOVERED || result == MF_DELAYED) ? 0 : -EBUSY; |
6a46079c AK |
1196 | } |
1197 | ||
bf181c58 NH |
1198 | static inline bool PageHWPoisonTakenOff(struct page *page) |
1199 | { | |
1200 | return PageHWPoison(page) && page_private(page) == MAGIC_HWPOISON; | |
1201 | } | |
1202 | ||
1203 | void SetPageHWPoisonTakenOff(struct page *page) | |
1204 | { | |
1205 | set_page_private(page, MAGIC_HWPOISON); | |
1206 | } | |
1207 | ||
1208 | void ClearPageHWPoisonTakenOff(struct page *page) | |
1209 | { | |
1210 | if (PageHWPoison(page)) | |
1211 | set_page_private(page, 0); | |
1212 | } | |
1213 | ||
25182f05 NH |
1214 | /* |
1215 | * Return true if a page type of a given page is supported by hwpoison | |
1216 | * mechanism (while handling could fail), otherwise false. This function | |
1217 | * does not return true for hugetlb or device memory pages, so it's assumed | |
1218 | * to be called only in the context where we never have such pages. | |
1219 | */ | |
bf6445bc | 1220 | static inline bool HWPoisonHandlable(struct page *page, unsigned long flags) |
25182f05 | 1221 | { |
3f871370 | 1222 | /* Soft offline could migrate non-LRU movable pages */ |
bf6445bc | 1223 | if ((flags & MF_SOFT_OFFLINE) && __PageMovable(page)) |
3f871370 | 1224 | return true; |
bf6445bc | 1225 | |
3f871370 | 1226 | return PageLRU(page) || is_free_buddy_page(page); |
25182f05 NH |
1227 | } |
1228 | ||
bf6445bc | 1229 | static int __get_hwpoison_page(struct page *page, unsigned long flags) |
ead07f6a NH |
1230 | { |
1231 | struct page *head = compound_head(page); | |
25182f05 NH |
1232 | int ret = 0; |
1233 | bool hugetlb = false; | |
1234 | ||
1235 | ret = get_hwpoison_huge_page(head, &hugetlb); | |
1236 | if (hugetlb) | |
1237 | return ret; | |
1238 | ||
1239 | /* | |
1240 | * This check prevents from calling get_hwpoison_unless_zero() | |
1241 | * for any unsupported type of page in order to reduce the risk of | |
1242 | * unexpected races caused by taking a page refcount. | |
1243 | */ | |
bf6445bc | 1244 | if (!HWPoisonHandlable(head, flags)) |
fcc00621 | 1245 | return -EBUSY; |
ead07f6a | 1246 | |
c2e7e00b KK |
1247 | if (get_page_unless_zero(head)) { |
1248 | if (head == compound_head(page)) | |
1249 | return 1; | |
1250 | ||
96f96763 | 1251 | pr_info("%#lx cannot catch tail\n", page_to_pfn(page)); |
c2e7e00b KK |
1252 | put_page(head); |
1253 | } | |
1254 | ||
1255 | return 0; | |
ead07f6a | 1256 | } |
ead07f6a | 1257 | |
2f714160 | 1258 | static int get_any_page(struct page *p, unsigned long flags) |
17e395b6 | 1259 | { |
2f714160 OS |
1260 | int ret = 0, pass = 0; |
1261 | bool count_increased = false; | |
17e395b6 | 1262 | |
2f714160 OS |
1263 | if (flags & MF_COUNT_INCREASED) |
1264 | count_increased = true; | |
1265 | ||
1266 | try_again: | |
0ed950d1 | 1267 | if (!count_increased) { |
bf6445bc | 1268 | ret = __get_hwpoison_page(p, flags); |
0ed950d1 NH |
1269 | if (!ret) { |
1270 | if (page_count(p)) { | |
1271 | /* We raced with an allocation, retry. */ | |
1272 | if (pass++ < 3) | |
1273 | goto try_again; | |
1274 | ret = -EBUSY; | |
1275 | } else if (!PageHuge(p) && !is_free_buddy_page(p)) { | |
1276 | /* We raced with put_page, retry. */ | |
1277 | if (pass++ < 3) | |
1278 | goto try_again; | |
1279 | ret = -EIO; | |
1280 | } | |
1281 | goto out; | |
1282 | } else if (ret == -EBUSY) { | |
fcc00621 NH |
1283 | /* |
1284 | * We raced with (possibly temporary) unhandlable | |
1285 | * page, retry. | |
1286 | */ | |
1287 | if (pass++ < 3) { | |
d0505e9f | 1288 | shake_page(p); |
2f714160 | 1289 | goto try_again; |
fcc00621 NH |
1290 | } |
1291 | ret = -EIO; | |
0ed950d1 | 1292 | goto out; |
2f714160 | 1293 | } |
0ed950d1 NH |
1294 | } |
1295 | ||
bf6445bc | 1296 | if (PageHuge(p) || HWPoisonHandlable(p, flags)) { |
0ed950d1 | 1297 | ret = 1; |
2f714160 | 1298 | } else { |
0ed950d1 NH |
1299 | /* |
1300 | * A page we cannot handle. Check whether we can turn | |
1301 | * it into something we can handle. | |
1302 | */ | |
1303 | if (pass++ < 3) { | |
2f714160 | 1304 | put_page(p); |
d0505e9f | 1305 | shake_page(p); |
0ed950d1 NH |
1306 | count_increased = false; |
1307 | goto try_again; | |
2f714160 | 1308 | } |
0ed950d1 NH |
1309 | put_page(p); |
1310 | ret = -EIO; | |
17e395b6 | 1311 | } |
0ed950d1 | 1312 | out: |
941ca063 | 1313 | if (ret == -EIO) |
96f96763 | 1314 | pr_err("%#lx: unhandlable page.\n", page_to_pfn(p)); |
941ca063 | 1315 | |
17e395b6 OS |
1316 | return ret; |
1317 | } | |
1318 | ||
bf181c58 NH |
1319 | static int __get_unpoison_page(struct page *page) |
1320 | { | |
1321 | struct page *head = compound_head(page); | |
1322 | int ret = 0; | |
1323 | bool hugetlb = false; | |
1324 | ||
1325 | ret = get_hwpoison_huge_page(head, &hugetlb); | |
1326 | if (hugetlb) | |
1327 | return ret; | |
1328 | ||
1329 | /* | |
1330 | * PageHWPoisonTakenOff pages are not only marked as PG_hwpoison, | |
1331 | * but also isolated from buddy freelist, so need to identify the | |
1332 | * state and have to cancel both operations to unpoison. | |
1333 | */ | |
1334 | if (PageHWPoisonTakenOff(page)) | |
1335 | return -EHWPOISON; | |
1336 | ||
1337 | return get_page_unless_zero(page) ? 1 : 0; | |
1338 | } | |
1339 | ||
0ed950d1 NH |
1340 | /** |
1341 | * get_hwpoison_page() - Get refcount for memory error handling | |
1342 | * @p: Raw error page (hit by memory error) | |
1343 | * @flags: Flags controlling behavior of error handling | |
1344 | * | |
1345 | * get_hwpoison_page() takes a page refcount of an error page to handle memory | |
1346 | * error on it, after checking that the error page is in a well-defined state | |
0b8f0d87 | 1347 | * (defined as a page-type we can successfully handle the memory error on it, |
0ed950d1 NH |
1348 | * such as LRU page and hugetlb page). |
1349 | * | |
1350 | * Memory error handling could be triggered at any time on any type of page, | |
1351 | * so it's prone to race with typical memory management lifecycle (like | |
1352 | * allocation and free). So to avoid such races, get_hwpoison_page() takes | |
1353 | * extra care for the error page's state (as done in __get_hwpoison_page()), | |
1354 | * and has some retry logic in get_any_page(). | |
1355 | * | |
bf181c58 NH |
1356 | * When called from unpoison_memory(), the caller should already ensure that |
1357 | * the given page has PG_hwpoison. So it's never reused for other page | |
1358 | * allocations, and __get_unpoison_page() never races with them. | |
1359 | * | |
0ed950d1 NH |
1360 | * Return: 0 on failure, |
1361 | * 1 on success for in-use pages in a well-defined state, | |
1362 | * -EIO for pages on which we can not handle memory errors, | |
1363 | * -EBUSY when get_hwpoison_page() has raced with page lifecycle | |
bf181c58 NH |
1364 | * operations like allocation and free, |
1365 | * -EHWPOISON when the page is hwpoisoned and taken off from buddy. | |
0ed950d1 NH |
1366 | */ |
1367 | static int get_hwpoison_page(struct page *p, unsigned long flags) | |
2f714160 OS |
1368 | { |
1369 | int ret; | |
1370 | ||
1371 | zone_pcp_disable(page_zone(p)); | |
bf181c58 NH |
1372 | if (flags & MF_UNPOISON) |
1373 | ret = __get_unpoison_page(p); | |
1374 | else | |
1375 | ret = get_any_page(p, flags); | |
2f714160 OS |
1376 | zone_pcp_enable(page_zone(p)); |
1377 | ||
1378 | return ret; | |
1379 | } | |
1380 | ||
6a46079c AK |
1381 | /* |
1382 | * Do all that is necessary to remove user space mappings. Unmap | |
1383 | * the pages and send SIGBUS to the processes if the data was dirty. | |
1384 | */ | |
666e5a40 | 1385 | static bool hwpoison_user_mappings(struct page *p, unsigned long pfn, |
ed8c2f49 | 1386 | int flags, struct page *hpage) |
6a46079c | 1387 | { |
869f7ee6 | 1388 | struct folio *folio = page_folio(hpage); |
36af6737 | 1389 | enum ttu_flags ttu = TTU_IGNORE_MLOCK | TTU_SYNC; |
6a46079c AK |
1390 | struct address_space *mapping; |
1391 | LIST_HEAD(tokill); | |
1fb08ac6 | 1392 | bool unmap_success; |
6751ed65 | 1393 | int kill = 1, forcekill; |
286c469a | 1394 | bool mlocked = PageMlocked(hpage); |
6a46079c | 1395 | |
93a9eb39 NH |
1396 | /* |
1397 | * Here we are interested only in user-mapped pages, so skip any | |
1398 | * other types of pages. | |
1399 | */ | |
1400 | if (PageReserved(p) || PageSlab(p)) | |
666e5a40 | 1401 | return true; |
93a9eb39 | 1402 | if (!(PageLRU(hpage) || PageHuge(p))) |
666e5a40 | 1403 | return true; |
6a46079c | 1404 | |
6a46079c AK |
1405 | /* |
1406 | * This check implies we don't kill processes if their pages | |
1407 | * are in the swap cache early. Those are always late kills. | |
1408 | */ | |
7af446a8 | 1409 | if (!page_mapped(hpage)) |
666e5a40 | 1410 | return true; |
1668bfd5 | 1411 | |
52089b14 | 1412 | if (PageKsm(p)) { |
96f96763 | 1413 | pr_err("%#lx: can't handle KSM pages.\n", pfn); |
666e5a40 | 1414 | return false; |
52089b14 | 1415 | } |
6a46079c AK |
1416 | |
1417 | if (PageSwapCache(p)) { | |
96f96763 | 1418 | pr_err("%#lx: keeping poisoned page in swap cache\n", pfn); |
6a46079c AK |
1419 | ttu |= TTU_IGNORE_HWPOISON; |
1420 | } | |
1421 | ||
1422 | /* | |
1423 | * Propagate the dirty bit from PTEs to struct page first, because we | |
1424 | * need this to decide if we should kill or just drop the page. | |
db0480b3 WF |
1425 | * XXX: the dirty test could be racy: set_page_dirty() may not always |
1426 | * be called inside page lock (it's recommended but not enforced). | |
6a46079c | 1427 | */ |
7af446a8 | 1428 | mapping = page_mapping(hpage); |
6751ed65 | 1429 | if (!(flags & MF_MUST_KILL) && !PageDirty(hpage) && mapping && |
f56753ac | 1430 | mapping_can_writeback(mapping)) { |
7af446a8 NH |
1431 | if (page_mkclean(hpage)) { |
1432 | SetPageDirty(hpage); | |
6a46079c AK |
1433 | } else { |
1434 | kill = 0; | |
1435 | ttu |= TTU_IGNORE_HWPOISON; | |
96f96763 | 1436 | pr_info("%#lx: corrupted page was clean: dropped without side effects\n", |
6a46079c AK |
1437 | pfn); |
1438 | } | |
1439 | } | |
1440 | ||
1441 | /* | |
1442 | * First collect all the processes that have the page | |
1443 | * mapped in dirty form. This has to be done before try_to_unmap, | |
1444 | * because ttu takes the rmap data structures down. | |
1445 | * | |
1446 | * Error handling: We ignore errors here because | |
1447 | * there's nothing that can be done. | |
1448 | */ | |
1449 | if (kill) | |
415c64c1 | 1450 | collect_procs(hpage, &tokill, flags & MF_ACTION_REQUIRED); |
6a46079c | 1451 | |
357670f7 ML |
1452 | if (PageHuge(hpage) && !PageAnon(hpage)) { |
1453 | /* | |
1454 | * For hugetlb pages in shared mappings, try_to_unmap | |
1455 | * could potentially call huge_pmd_unshare. Because of | |
1456 | * this, take semaphore in write mode here and set | |
1457 | * TTU_RMAP_LOCKED to indicate we have taken the lock | |
1458 | * at this higher level. | |
1459 | */ | |
1460 | mapping = hugetlb_page_mapping_lock_write(hpage); | |
1461 | if (mapping) { | |
9030fb0b | 1462 | try_to_unmap(folio, ttu|TTU_RMAP_LOCKED); |
357670f7 ML |
1463 | i_mmap_unlock_write(mapping); |
1464 | } else | |
96f96763 | 1465 | pr_info("%#lx: could not lock mapping for mapped huge page\n", pfn); |
c0d0381a | 1466 | } else { |
9030fb0b | 1467 | try_to_unmap(folio, ttu); |
c0d0381a | 1468 | } |
1fb08ac6 YS |
1469 | |
1470 | unmap_success = !page_mapped(hpage); | |
666e5a40 | 1471 | if (!unmap_success) |
96f96763 | 1472 | pr_err("%#lx: failed to unmap page (mapcount=%d)\n", |
1170532b | 1473 | pfn, page_mapcount(hpage)); |
a6d30ddd | 1474 | |
286c469a NH |
1475 | /* |
1476 | * try_to_unmap() might put mlocked page in lru cache, so call | |
1477 | * shake_page() again to ensure that it's flushed. | |
1478 | */ | |
1479 | if (mlocked) | |
d0505e9f | 1480 | shake_page(hpage); |
286c469a | 1481 | |
6a46079c AK |
1482 | /* |
1483 | * Now that the dirty bit has been propagated to the | |
1484 | * struct page and all unmaps done we can decide if | |
1485 | * killing is needed or not. Only kill when the page | |
6751ed65 TL |
1486 | * was dirty or the process is not restartable, |
1487 | * otherwise the tokill list is merely | |
6a46079c AK |
1488 | * freed. When there was a problem unmapping earlier |
1489 | * use a more force-full uncatchable kill to prevent | |
1490 | * any accesses to the poisoned memory. | |
1491 | */ | |
415c64c1 | 1492 | forcekill = PageDirty(hpage) || (flags & MF_MUST_KILL); |
ae1139ec | 1493 | kill_procs(&tokill, forcekill, !unmap_success, pfn, flags); |
1668bfd5 | 1494 | |
666e5a40 | 1495 | return unmap_success; |
6a46079c AK |
1496 | } |
1497 | ||
0348d2eb NH |
1498 | static int identify_page_state(unsigned long pfn, struct page *p, |
1499 | unsigned long page_flags) | |
761ad8d7 NH |
1500 | { |
1501 | struct page_state *ps; | |
0348d2eb NH |
1502 | |
1503 | /* | |
1504 | * The first check uses the current page flags which may not have any | |
1505 | * relevant information. The second check with the saved page flags is | |
1506 | * carried out only if the first check can't determine the page status. | |
1507 | */ | |
1508 | for (ps = error_states;; ps++) | |
1509 | if ((p->flags & ps->mask) == ps->res) | |
1510 | break; | |
1511 | ||
1512 | page_flags |= (p->flags & (1UL << PG_dirty)); | |
1513 | ||
1514 | if (!ps->mask) | |
1515 | for (ps = error_states;; ps++) | |
1516 | if ((page_flags & ps->mask) == ps->res) | |
1517 | break; | |
1518 | return page_action(ps, p, pfn); | |
1519 | } | |
1520 | ||
694bf0b0 OS |
1521 | static int try_to_split_thp_page(struct page *page, const char *msg) |
1522 | { | |
1523 | lock_page(page); | |
4966455d | 1524 | if (unlikely(split_huge_page(page))) { |
694bf0b0 OS |
1525 | unsigned long pfn = page_to_pfn(page); |
1526 | ||
1527 | unlock_page(page); | |
4966455d | 1528 | pr_info("%s: %#lx: thp split failed\n", msg, pfn); |
694bf0b0 OS |
1529 | put_page(page); |
1530 | return -EBUSY; | |
1531 | } | |
1532 | unlock_page(page); | |
1533 | ||
1534 | return 0; | |
1535 | } | |
1536 | ||
00cc790e SR |
1537 | static void unmap_and_kill(struct list_head *to_kill, unsigned long pfn, |
1538 | struct address_space *mapping, pgoff_t index, int flags) | |
1539 | { | |
1540 | struct to_kill *tk; | |
1541 | unsigned long size = 0; | |
1542 | ||
1543 | list_for_each_entry(tk, to_kill, nd) | |
1544 | if (tk->size_shift) | |
1545 | size = max(size, 1UL << tk->size_shift); | |
1546 | ||
1547 | if (size) { | |
1548 | /* | |
1549 | * Unmap the largest mapping to avoid breaking up device-dax | |
1550 | * mappings which are constant size. The actual size of the | |
1551 | * mapping being torn down is communicated in siginfo, see | |
1552 | * kill_proc() | |
1553 | */ | |
1554 | loff_t start = (index << PAGE_SHIFT) & ~(size - 1); | |
1555 | ||
1556 | unmap_mapping_range(mapping, start, size, 0); | |
1557 | } | |
1558 | ||
1559 | kill_procs(to_kill, flags & MF_MUST_KILL, false, pfn, flags); | |
1560 | } | |
1561 | ||
1562 | static int mf_generic_kill_procs(unsigned long long pfn, int flags, | |
1563 | struct dev_pagemap *pgmap) | |
1564 | { | |
1565 | struct page *page = pfn_to_page(pfn); | |
1566 | LIST_HEAD(to_kill); | |
1567 | dax_entry_t cookie; | |
1568 | int rc = 0; | |
1569 | ||
1570 | /* | |
1571 | * Pages instantiated by device-dax (not filesystem-dax) | |
1572 | * may be compound pages. | |
1573 | */ | |
1574 | page = compound_head(page); | |
1575 | ||
1576 | /* | |
1577 | * Prevent the inode from being freed while we are interrogating | |
1578 | * the address_space, typically this would be handled by | |
1579 | * lock_page(), but dax pages do not use the page lock. This | |
1580 | * also prevents changes to the mapping of this pfn until | |
1581 | * poison signaling is complete. | |
1582 | */ | |
1583 | cookie = dax_lock_page(page); | |
1584 | if (!cookie) | |
1585 | return -EBUSY; | |
1586 | ||
1587 | if (hwpoison_filter(page)) { | |
1588 | rc = -EOPNOTSUPP; | |
1589 | goto unlock; | |
1590 | } | |
1591 | ||
1592 | switch (pgmap->type) { | |
1593 | case MEMORY_DEVICE_PRIVATE: | |
1594 | case MEMORY_DEVICE_COHERENT: | |
1595 | /* | |
1596 | * TODO: Handle device pages which may need coordination | |
1597 | * with device-side memory. | |
1598 | */ | |
1599 | rc = -ENXIO; | |
1600 | goto unlock; | |
1601 | default: | |
1602 | break; | |
1603 | } | |
1604 | ||
1605 | /* | |
1606 | * Use this flag as an indication that the dax page has been | |
1607 | * remapped UC to prevent speculative consumption of poison. | |
1608 | */ | |
1609 | SetPageHWPoison(page); | |
1610 | ||
1611 | /* | |
1612 | * Unlike System-RAM there is no possibility to swap in a | |
1613 | * different physical page at a given virtual address, so all | |
1614 | * userspace consumption of ZONE_DEVICE memory necessitates | |
1615 | * SIGBUS (i.e. MF_MUST_KILL) | |
1616 | */ | |
1617 | flags |= MF_ACTION_REQUIRED | MF_MUST_KILL; | |
1618 | collect_procs(page, &to_kill, true); | |
1619 | ||
1620 | unmap_and_kill(&to_kill, pfn, page->mapping, page->index, flags); | |
1621 | unlock: | |
1622 | dax_unlock_page(page, cookie); | |
1623 | return rc; | |
1624 | } | |
1625 | ||
c36e2024 SR |
1626 | #ifdef CONFIG_FS_DAX |
1627 | /** | |
1628 | * mf_dax_kill_procs - Collect and kill processes who are using this file range | |
1629 | * @mapping: address_space of the file in use | |
1630 | * @index: start pgoff of the range within the file | |
1631 | * @count: length of the range, in unit of PAGE_SIZE | |
1632 | * @mf_flags: memory failure flags | |
1633 | */ | |
1634 | int mf_dax_kill_procs(struct address_space *mapping, pgoff_t index, | |
1635 | unsigned long count, int mf_flags) | |
1636 | { | |
1637 | LIST_HEAD(to_kill); | |
1638 | dax_entry_t cookie; | |
1639 | struct page *page; | |
1640 | size_t end = index + count; | |
1641 | ||
1642 | mf_flags |= MF_ACTION_REQUIRED | MF_MUST_KILL; | |
1643 | ||
1644 | for (; index < end; index++) { | |
1645 | page = NULL; | |
1646 | cookie = dax_lock_mapping_entry(mapping, index, &page); | |
1647 | if (!cookie) | |
1648 | return -EBUSY; | |
1649 | if (!page) | |
1650 | goto unlock; | |
1651 | ||
1652 | SetPageHWPoison(page); | |
1653 | ||
1654 | collect_procs_fsdax(page, mapping, index, &to_kill); | |
1655 | unmap_and_kill(&to_kill, page_to_pfn(page), mapping, | |
1656 | index, mf_flags); | |
1657 | unlock: | |
1658 | dax_unlock_mapping_entry(mapping, index, cookie); | |
1659 | } | |
1660 | return 0; | |
1661 | } | |
1662 | EXPORT_SYMBOL_GPL(mf_dax_kill_procs); | |
1663 | #endif /* CONFIG_FS_DAX */ | |
1664 | ||
405ce051 NH |
1665 | /* |
1666 | * Called from hugetlb code with hugetlb_lock held. | |
1667 | * | |
1668 | * Return values: | |
1669 | * 0 - free hugepage | |
1670 | * 1 - in-use hugepage | |
1671 | * 2 - not a hugepage | |
1672 | * -EBUSY - the hugepage is busy (try to retry) | |
1673 | * -EHWPOISON - the hugepage is already hwpoisoned | |
1674 | */ | |
1675 | int __get_huge_page_for_hwpoison(unsigned long pfn, int flags) | |
1676 | { | |
1677 | struct page *page = pfn_to_page(pfn); | |
1678 | struct page *head = compound_head(page); | |
1679 | int ret = 2; /* fallback to normal page handling */ | |
1680 | bool count_increased = false; | |
1681 | ||
1682 | if (!PageHeadHuge(head)) | |
1683 | goto out; | |
1684 | ||
1685 | if (flags & MF_COUNT_INCREASED) { | |
1686 | ret = 1; | |
1687 | count_increased = true; | |
b283d983 NH |
1688 | } else if (HPageFreed(head)) { |
1689 | ret = 0; | |
1690 | } else if (HPageMigratable(head)) { | |
405ce051 NH |
1691 | ret = get_page_unless_zero(head); |
1692 | if (ret) | |
1693 | count_increased = true; | |
1694 | } else { | |
1695 | ret = -EBUSY; | |
1696 | goto out; | |
1697 | } | |
1698 | ||
1699 | if (TestSetPageHWPoison(head)) { | |
1700 | ret = -EHWPOISON; | |
1701 | goto out; | |
1702 | } | |
1703 | ||
1704 | return ret; | |
1705 | out: | |
1706 | if (count_increased) | |
1707 | put_page(head); | |
1708 | return ret; | |
1709 | } | |
1710 | ||
1711 | #ifdef CONFIG_HUGETLB_PAGE | |
1712 | /* | |
1713 | * Taking refcount of hugetlb pages needs extra care about race conditions | |
1714 | * with basic operations like hugepage allocation/free/demotion. | |
1715 | * So some of prechecks for hwpoison (pinning, and testing/setting | |
1716 | * PageHWPoison) should be done in single hugetlb_lock range. | |
1717 | */ | |
1718 | static int try_memory_failure_hugetlb(unsigned long pfn, int flags, int *hugetlb) | |
0348d2eb | 1719 | { |
761ad8d7 | 1720 | int res; |
405ce051 NH |
1721 | struct page *p = pfn_to_page(pfn); |
1722 | struct page *head; | |
761ad8d7 | 1723 | unsigned long page_flags; |
405ce051 | 1724 | bool retry = true; |
761ad8d7 | 1725 | |
405ce051 NH |
1726 | *hugetlb = 1; |
1727 | retry: | |
1728 | res = get_huge_page_for_hwpoison(pfn, flags); | |
1729 | if (res == 2) { /* fallback to normal page handling */ | |
1730 | *hugetlb = 0; | |
1731 | return 0; | |
1732 | } else if (res == -EHWPOISON) { | |
96f96763 | 1733 | pr_err("%#lx: already hardware poisoned\n", pfn); |
405ce051 NH |
1734 | if (flags & MF_ACTION_REQUIRED) { |
1735 | head = compound_head(p); | |
a3f5d80e | 1736 | res = kill_accessing_process(current, page_to_pfn(head), flags); |
405ce051 NH |
1737 | } |
1738 | return res; | |
1739 | } else if (res == -EBUSY) { | |
1740 | if (retry) { | |
1741 | retry = false; | |
1742 | goto retry; | |
1743 | } | |
1744 | action_result(pfn, MF_MSG_UNKNOWN, MF_IGNORED); | |
a3f5d80e | 1745 | return res; |
761ad8d7 NH |
1746 | } |
1747 | ||
405ce051 NH |
1748 | head = compound_head(p); |
1749 | lock_page(head); | |
1750 | ||
1751 | if (hwpoison_filter(p)) { | |
1752 | ClearPageHWPoison(head); | |
1753 | res = -EOPNOTSUPP; | |
1754 | goto out; | |
1755 | } | |
1756 | ||
405ce051 NH |
1757 | /* |
1758 | * Handling free hugepage. The possible race with hugepage allocation | |
1759 | * or demotion can be prevented by PageHWPoison flag. | |
1760 | */ | |
1761 | if (res == 0) { | |
1762 | unlock_page(head); | |
1763 | res = MF_FAILED; | |
1764 | if (__page_handle_poison(p)) { | |
1765 | page_ref_inc(p); | |
1766 | res = MF_RECOVERED; | |
761ad8d7 | 1767 | } |
405ce051 NH |
1768 | action_result(pfn, MF_MSG_FREE_HUGE, res); |
1769 | return res == MF_RECOVERED ? 0 : -EBUSY; | |
761ad8d7 NH |
1770 | } |
1771 | ||
761ad8d7 NH |
1772 | page_flags = head->flags; |
1773 | ||
31286a84 NH |
1774 | /* |
1775 | * TODO: hwpoison for pud-sized hugetlb doesn't work right now, so | |
1776 | * simply disable it. In order to make it work properly, we need | |
1777 | * make sure that: | |
1778 | * - conversion of a pud that maps an error hugetlb into hwpoison | |
1779 | * entry properly works, and | |
1780 | * - other mm code walking over page table is aware of pud-aligned | |
1781 | * hwpoison entries. | |
1782 | */ | |
1783 | if (huge_page_size(page_hstate(head)) > PMD_SIZE) { | |
1784 | action_result(pfn, MF_MSG_NON_PMD_HUGE, MF_IGNORED); | |
1785 | res = -EBUSY; | |
1786 | goto out; | |
1787 | } | |
1788 | ||
ed8c2f49 | 1789 | if (!hwpoison_user_mappings(p, pfn, flags, head)) { |
761ad8d7 NH |
1790 | action_result(pfn, MF_MSG_UNMAP_FAILED, MF_IGNORED); |
1791 | res = -EBUSY; | |
1792 | goto out; | |
1793 | } | |
1794 | ||
ea6d0630 | 1795 | return identify_page_state(pfn, p, page_flags); |
761ad8d7 NH |
1796 | out: |
1797 | unlock_page(head); | |
1798 | return res; | |
1799 | } | |
00cc790e | 1800 | |
405ce051 NH |
1801 | #else |
1802 | static inline int try_memory_failure_hugetlb(unsigned long pfn, int flags, int *hugetlb) | |
1803 | { | |
1804 | return 0; | |
1805 | } | |
00cc790e SR |
1806 | |
1807 | #endif /* CONFIG_HUGETLB_PAGE */ | |
761ad8d7 | 1808 | |
6100e34b DW |
1809 | static int memory_failure_dev_pagemap(unsigned long pfn, int flags, |
1810 | struct dev_pagemap *pgmap) | |
1811 | { | |
1812 | struct page *page = pfn_to_page(pfn); | |
00cc790e | 1813 | int rc = -ENXIO; |
6100e34b | 1814 | |
1e8aaedb OS |
1815 | if (flags & MF_COUNT_INCREASED) |
1816 | /* | |
1817 | * Drop the extra refcount in case we come from madvise(). | |
1818 | */ | |
1819 | put_page(page); | |
1820 | ||
34dc45be | 1821 | /* device metadata space is not recoverable */ |
00cc790e | 1822 | if (!pgmap_pfn_valid(pgmap, pfn)) |
34dc45be | 1823 | goto out; |
61e28cf0 | 1824 | |
6100e34b | 1825 | /* |
33a8f7f2 SR |
1826 | * Call driver's implementation to handle the memory failure, otherwise |
1827 | * fall back to generic handler. | |
6100e34b | 1828 | */ |
33a8f7f2 SR |
1829 | if (pgmap->ops->memory_failure) { |
1830 | rc = pgmap->ops->memory_failure(pgmap, pfn, 1, flags); | |
6100e34b | 1831 | /* |
33a8f7f2 SR |
1832 | * Fall back to generic handler too if operation is not |
1833 | * supported inside the driver/device/filesystem. | |
6100e34b | 1834 | */ |
33a8f7f2 SR |
1835 | if (rc != -EOPNOTSUPP) |
1836 | goto out; | |
6100e34b DW |
1837 | } |
1838 | ||
00cc790e | 1839 | rc = mf_generic_kill_procs(pfn, flags, pgmap); |
6100e34b DW |
1840 | out: |
1841 | /* drop pgmap ref acquired in caller */ | |
1842 | put_dev_pagemap(pgmap); | |
1843 | action_result(pfn, MF_MSG_DAX, rc ? MF_FAILED : MF_RECOVERED); | |
1844 | return rc; | |
1845 | } | |
1846 | ||
91d00547 NH |
1847 | static DEFINE_MUTEX(mf_mutex); |
1848 | ||
cd42f4a3 TL |
1849 | /** |
1850 | * memory_failure - Handle memory failure of a page. | |
1851 | * @pfn: Page Number of the corrupted page | |
cd42f4a3 TL |
1852 | * @flags: fine tune action taken |
1853 | * | |
1854 | * This function is called by the low level machine check code | |
1855 | * of an architecture when it detects hardware memory corruption | |
1856 | * of a page. It tries its best to recover, which includes | |
1857 | * dropping pages, killing processes etc. | |
1858 | * | |
1859 | * The function is primarily of use for corruptions that | |
1860 | * happen outside the current execution context (e.g. when | |
1861 | * detected by a background scrubber) | |
1862 | * | |
1863 | * Must run in process context (e.g. a work queue) with interrupts | |
1864 | * enabled and no spinlocks hold. | |
d1fe111f | 1865 | * |
1866 | * Return: 0 for successfully handled the memory error, | |
9113eaf3 | 1867 | * -EOPNOTSUPP for hwpoison_filter() filtered the error event, |
d1fe111f | 1868 | * < 0(except -EOPNOTSUPP) on failure. |
cd42f4a3 | 1869 | */ |
83b57531 | 1870 | int memory_failure(unsigned long pfn, int flags) |
6a46079c | 1871 | { |
6a46079c | 1872 | struct page *p; |
7af446a8 | 1873 | struct page *hpage; |
6100e34b | 1874 | struct dev_pagemap *pgmap; |
171936dd | 1875 | int res = 0; |
524fca1e | 1876 | unsigned long page_flags; |
a8b2c2ce | 1877 | bool retry = true; |
405ce051 | 1878 | int hugetlb = 0; |
6a46079c AK |
1879 | |
1880 | if (!sysctl_memory_failure_recovery) | |
83b57531 | 1881 | panic("Memory failure on page %lx", pfn); |
6a46079c | 1882 | |
03b122da TL |
1883 | mutex_lock(&mf_mutex); |
1884 | ||
67f22ba7 | 1885 | if (!(flags & MF_SW_SIMULATED)) |
1886 | hw_memory_failure = true; | |
1887 | ||
96c804a6 DH |
1888 | p = pfn_to_online_page(pfn); |
1889 | if (!p) { | |
03b122da TL |
1890 | res = arch_memory_failure(pfn, flags); |
1891 | if (res == 0) | |
1892 | goto unlock_mutex; | |
1893 | ||
96c804a6 DH |
1894 | if (pfn_valid(pfn)) { |
1895 | pgmap = get_dev_pagemap(pfn, NULL); | |
03b122da TL |
1896 | if (pgmap) { |
1897 | res = memory_failure_dev_pagemap(pfn, flags, | |
1898 | pgmap); | |
1899 | goto unlock_mutex; | |
1900 | } | |
96c804a6 | 1901 | } |
96f96763 | 1902 | pr_err("%#lx: memory outside kernel control\n", pfn); |
03b122da TL |
1903 | res = -ENXIO; |
1904 | goto unlock_mutex; | |
6a46079c AK |
1905 | } |
1906 | ||
a8b2c2ce | 1907 | try_again: |
405ce051 NH |
1908 | res = try_memory_failure_hugetlb(pfn, flags, &hugetlb); |
1909 | if (hugetlb) | |
171936dd | 1910 | goto unlock_mutex; |
171936dd | 1911 | |
6a46079c | 1912 | if (TestSetPageHWPoison(p)) { |
96f96763 | 1913 | pr_err("%#lx: already hardware poisoned\n", pfn); |
47af12ba | 1914 | res = -EHWPOISON; |
a3f5d80e NH |
1915 | if (flags & MF_ACTION_REQUIRED) |
1916 | res = kill_accessing_process(current, pfn, flags); | |
f361e246 NH |
1917 | if (flags & MF_COUNT_INCREASED) |
1918 | put_page(p); | |
171936dd | 1919 | goto unlock_mutex; |
6a46079c AK |
1920 | } |
1921 | ||
75ee64b3 | 1922 | hpage = compound_head(p); |
6a46079c AK |
1923 | |
1924 | /* | |
1925 | * We need/can do nothing about count=0 pages. | |
1926 | * 1) it's a free page, and therefore in safe hand: | |
1927 | * prep_new_page() will be the gate keeper. | |
761ad8d7 | 1928 | * 2) it's part of a non-compound high order page. |
6a46079c AK |
1929 | * Implies some kernel user: cannot stop them from |
1930 | * R/W the page; let's pray that the page has been | |
1931 | * used and will be freed some time later. | |
1932 | * In fact it's dangerous to directly bump up page count from 0, | |
1c4c3b99 | 1933 | * that may make page_ref_freeze()/page_ref_unfreeze() mismatch. |
6a46079c | 1934 | */ |
0ed950d1 NH |
1935 | if (!(flags & MF_COUNT_INCREASED)) { |
1936 | res = get_hwpoison_page(p, flags); | |
1937 | if (!res) { | |
1938 | if (is_free_buddy_page(p)) { | |
1939 | if (take_page_off_buddy(p)) { | |
1940 | page_ref_inc(p); | |
1941 | res = MF_RECOVERED; | |
1942 | } else { | |
1943 | /* We lost the race, try again */ | |
1944 | if (retry) { | |
1945 | ClearPageHWPoison(p); | |
0ed950d1 NH |
1946 | retry = false; |
1947 | goto try_again; | |
1948 | } | |
1949 | res = MF_FAILED; | |
a8b2c2ce | 1950 | } |
0ed950d1 NH |
1951 | action_result(pfn, MF_MSG_BUDDY, res); |
1952 | res = res == MF_RECOVERED ? 0 : -EBUSY; | |
1953 | } else { | |
1954 | action_result(pfn, MF_MSG_KERNEL_HIGH_ORDER, MF_IGNORED); | |
1955 | res = -EBUSY; | |
a8b2c2ce | 1956 | } |
0ed950d1 NH |
1957 | goto unlock_mutex; |
1958 | } else if (res < 0) { | |
1959 | action_result(pfn, MF_MSG_UNKNOWN, MF_IGNORED); | |
171936dd | 1960 | res = -EBUSY; |
0ed950d1 | 1961 | goto unlock_mutex; |
8d22ba1b | 1962 | } |
6a46079c AK |
1963 | } |
1964 | ||
761ad8d7 | 1965 | if (PageTransHuge(hpage)) { |
eac96c3e YS |
1966 | /* |
1967 | * The flag must be set after the refcount is bumped | |
1968 | * otherwise it may race with THP split. | |
1969 | * And the flag can't be set in get_hwpoison_page() since | |
1970 | * it is called by soft offline too and it is just called | |
1971 | * for !MF_COUNT_INCREASE. So here seems to be the best | |
1972 | * place. | |
1973 | * | |
1974 | * Don't need care about the above error handling paths for | |
1975 | * get_hwpoison_page() since they handle either free page | |
1976 | * or unhandlable page. The refcount is bumped iff the | |
1977 | * page is a valid handlable page. | |
1978 | */ | |
1979 | SetPageHasHWPoisoned(hpage); | |
5d1fd5dc NH |
1980 | if (try_to_split_thp_page(p, "Memory Failure") < 0) { |
1981 | action_result(pfn, MF_MSG_UNSPLIT_THP, MF_IGNORED); | |
171936dd TL |
1982 | res = -EBUSY; |
1983 | goto unlock_mutex; | |
5d1fd5dc | 1984 | } |
415c64c1 | 1985 | VM_BUG_ON_PAGE(!page_count(p), p); |
415c64c1 NH |
1986 | } |
1987 | ||
e43c3afb WF |
1988 | /* |
1989 | * We ignore non-LRU pages for good reasons. | |
1990 | * - PG_locked is only well defined for LRU pages and a few others | |
48c935ad | 1991 | * - to avoid races with __SetPageLocked() |
e43c3afb WF |
1992 | * - to avoid races with __SetPageSlab*() (and more non-atomic ops) |
1993 | * The check (unnecessarily) ignores LRU pages being isolated and | |
1994 | * walked by the page reclaim code, however that's not a big loss. | |
1995 | */ | |
d0505e9f | 1996 | shake_page(p); |
e43c3afb | 1997 | |
761ad8d7 | 1998 | lock_page(p); |
847ce401 | 1999 | |
f37d4298 | 2000 | /* |
75ee64b3 ML |
2001 | * We're only intended to deal with the non-Compound page here. |
2002 | * However, the page could have changed compound pages due to | |
2003 | * race window. If this happens, we could try again to hopefully | |
2004 | * handle the page next round. | |
f37d4298 | 2005 | */ |
75ee64b3 ML |
2006 | if (PageCompound(p)) { |
2007 | if (retry) { | |
e240ac52 | 2008 | ClearPageHWPoison(p); |
75ee64b3 ML |
2009 | unlock_page(p); |
2010 | put_page(p); | |
2011 | flags &= ~MF_COUNT_INCREASED; | |
2012 | retry = false; | |
2013 | goto try_again; | |
2014 | } | |
cc637b17 | 2015 | action_result(pfn, MF_MSG_DIFFERENT_COMPOUND, MF_IGNORED); |
f37d4298 | 2016 | res = -EBUSY; |
171936dd | 2017 | goto unlock_page; |
f37d4298 AK |
2018 | } |
2019 | ||
524fca1e NH |
2020 | /* |
2021 | * We use page flags to determine what action should be taken, but | |
2022 | * the flags can be modified by the error containment action. One | |
2023 | * example is an mlocked page, where PG_mlocked is cleared by | |
2024 | * page_remove_rmap() in try_to_unmap_one(). So to determine page status | |
2025 | * correctly, we save a copy of the page flags at this time. | |
2026 | */ | |
7d9d46ac | 2027 | page_flags = p->flags; |
524fca1e | 2028 | |
7c116f2b | 2029 | if (hwpoison_filter(p)) { |
e240ac52 | 2030 | TestClearPageHWPoison(p); |
761ad8d7 | 2031 | unlock_page(p); |
dd6e2402 | 2032 | put_page(p); |
d1fe111f | 2033 | res = -EOPNOTSUPP; |
171936dd | 2034 | goto unlock_mutex; |
7c116f2b | 2035 | } |
847ce401 | 2036 | |
e8675d29 | 2037 | /* |
2038 | * __munlock_pagevec may clear a writeback page's LRU flag without | |
2039 | * page_lock. We need wait writeback completion for this page or it | |
2040 | * may trigger vfs BUG while evict inode. | |
2041 | */ | |
b04d3eeb | 2042 | if (!PageLRU(p) && !PageWriteback(p)) |
0bc1f8b0 CY |
2043 | goto identify_page_state; |
2044 | ||
6edd6cc6 NH |
2045 | /* |
2046 | * It's very difficult to mess with pages currently under IO | |
2047 | * and in many cases impossible, so we just avoid it here. | |
2048 | */ | |
6a46079c AK |
2049 | wait_on_page_writeback(p); |
2050 | ||
2051 | /* | |
2052 | * Now take care of user space mappings. | |
6ffcd825 | 2053 | * Abort on fail: __filemap_remove_folio() assumes unmapped page. |
6a46079c | 2054 | */ |
ed8c2f49 | 2055 | if (!hwpoison_user_mappings(p, pfn, flags, p)) { |
cc637b17 | 2056 | action_result(pfn, MF_MSG_UNMAP_FAILED, MF_IGNORED); |
1668bfd5 | 2057 | res = -EBUSY; |
171936dd | 2058 | goto unlock_page; |
1668bfd5 | 2059 | } |
6a46079c AK |
2060 | |
2061 | /* | |
2062 | * Torn down by someone else? | |
2063 | */ | |
dc2a1cbf | 2064 | if (PageLRU(p) && !PageSwapCache(p) && p->mapping == NULL) { |
cc637b17 | 2065 | action_result(pfn, MF_MSG_TRUNCATED_LRU, MF_IGNORED); |
d95ea51e | 2066 | res = -EBUSY; |
171936dd | 2067 | goto unlock_page; |
6a46079c AK |
2068 | } |
2069 | ||
0bc1f8b0 | 2070 | identify_page_state: |
0348d2eb | 2071 | res = identify_page_state(pfn, p, page_flags); |
ea6d0630 NH |
2072 | mutex_unlock(&mf_mutex); |
2073 | return res; | |
171936dd | 2074 | unlock_page: |
761ad8d7 | 2075 | unlock_page(p); |
171936dd TL |
2076 | unlock_mutex: |
2077 | mutex_unlock(&mf_mutex); | |
6a46079c AK |
2078 | return res; |
2079 | } | |
cd42f4a3 | 2080 | EXPORT_SYMBOL_GPL(memory_failure); |
847ce401 | 2081 | |
ea8f5fb8 HY |
2082 | #define MEMORY_FAILURE_FIFO_ORDER 4 |
2083 | #define MEMORY_FAILURE_FIFO_SIZE (1 << MEMORY_FAILURE_FIFO_ORDER) | |
2084 | ||
2085 | struct memory_failure_entry { | |
2086 | unsigned long pfn; | |
ea8f5fb8 HY |
2087 | int flags; |
2088 | }; | |
2089 | ||
2090 | struct memory_failure_cpu { | |
2091 | DECLARE_KFIFO(fifo, struct memory_failure_entry, | |
2092 | MEMORY_FAILURE_FIFO_SIZE); | |
2093 | spinlock_t lock; | |
2094 | struct work_struct work; | |
2095 | }; | |
2096 | ||
2097 | static DEFINE_PER_CPU(struct memory_failure_cpu, memory_failure_cpu); | |
2098 | ||
2099 | /** | |
2100 | * memory_failure_queue - Schedule handling memory failure of a page. | |
2101 | * @pfn: Page Number of the corrupted page | |
ea8f5fb8 HY |
2102 | * @flags: Flags for memory failure handling |
2103 | * | |
2104 | * This function is called by the low level hardware error handler | |
2105 | * when it detects hardware memory corruption of a page. It schedules | |
2106 | * the recovering of error page, including dropping pages, killing | |
2107 | * processes etc. | |
2108 | * | |
2109 | * The function is primarily of use for corruptions that | |
2110 | * happen outside the current execution context (e.g. when | |
2111 | * detected by a background scrubber) | |
2112 | * | |
2113 | * Can run in IRQ context. | |
2114 | */ | |
83b57531 | 2115 | void memory_failure_queue(unsigned long pfn, int flags) |
ea8f5fb8 HY |
2116 | { |
2117 | struct memory_failure_cpu *mf_cpu; | |
2118 | unsigned long proc_flags; | |
2119 | struct memory_failure_entry entry = { | |
2120 | .pfn = pfn, | |
ea8f5fb8 HY |
2121 | .flags = flags, |
2122 | }; | |
2123 | ||
2124 | mf_cpu = &get_cpu_var(memory_failure_cpu); | |
2125 | spin_lock_irqsave(&mf_cpu->lock, proc_flags); | |
498d319b | 2126 | if (kfifo_put(&mf_cpu->fifo, entry)) |
ea8f5fb8 HY |
2127 | schedule_work_on(smp_processor_id(), &mf_cpu->work); |
2128 | else | |
96f96763 | 2129 | pr_err("buffer overflow when queuing memory failure at %#lx\n", |
ea8f5fb8 HY |
2130 | pfn); |
2131 | spin_unlock_irqrestore(&mf_cpu->lock, proc_flags); | |
2132 | put_cpu_var(memory_failure_cpu); | |
2133 | } | |
2134 | EXPORT_SYMBOL_GPL(memory_failure_queue); | |
2135 | ||
2136 | static void memory_failure_work_func(struct work_struct *work) | |
2137 | { | |
2138 | struct memory_failure_cpu *mf_cpu; | |
2139 | struct memory_failure_entry entry = { 0, }; | |
2140 | unsigned long proc_flags; | |
2141 | int gotten; | |
2142 | ||
06202231 | 2143 | mf_cpu = container_of(work, struct memory_failure_cpu, work); |
ea8f5fb8 HY |
2144 | for (;;) { |
2145 | spin_lock_irqsave(&mf_cpu->lock, proc_flags); | |
2146 | gotten = kfifo_get(&mf_cpu->fifo, &entry); | |
2147 | spin_unlock_irqrestore(&mf_cpu->lock, proc_flags); | |
2148 | if (!gotten) | |
2149 | break; | |
cf870c70 | 2150 | if (entry.flags & MF_SOFT_OFFLINE) |
feec24a6 | 2151 | soft_offline_page(entry.pfn, entry.flags); |
cf870c70 | 2152 | else |
83b57531 | 2153 | memory_failure(entry.pfn, entry.flags); |
ea8f5fb8 HY |
2154 | } |
2155 | } | |
2156 | ||
06202231 JM |
2157 | /* |
2158 | * Process memory_failure work queued on the specified CPU. | |
2159 | * Used to avoid return-to-userspace racing with the memory_failure workqueue. | |
2160 | */ | |
2161 | void memory_failure_queue_kick(int cpu) | |
2162 | { | |
2163 | struct memory_failure_cpu *mf_cpu; | |
2164 | ||
2165 | mf_cpu = &per_cpu(memory_failure_cpu, cpu); | |
2166 | cancel_work_sync(&mf_cpu->work); | |
2167 | memory_failure_work_func(&mf_cpu->work); | |
2168 | } | |
2169 | ||
ea8f5fb8 HY |
2170 | static int __init memory_failure_init(void) |
2171 | { | |
2172 | struct memory_failure_cpu *mf_cpu; | |
2173 | int cpu; | |
2174 | ||
2175 | for_each_possible_cpu(cpu) { | |
2176 | mf_cpu = &per_cpu(memory_failure_cpu, cpu); | |
2177 | spin_lock_init(&mf_cpu->lock); | |
2178 | INIT_KFIFO(mf_cpu->fifo); | |
2179 | INIT_WORK(&mf_cpu->work, memory_failure_work_func); | |
2180 | } | |
2181 | ||
2182 | return 0; | |
2183 | } | |
2184 | core_initcall(memory_failure_init); | |
2185 | ||
96f96763 KW |
2186 | #undef pr_fmt |
2187 | #define pr_fmt(fmt) "" fmt | |
a5f65109 NH |
2188 | #define unpoison_pr_info(fmt, pfn, rs) \ |
2189 | ({ \ | |
2190 | if (__ratelimit(rs)) \ | |
2191 | pr_info(fmt, pfn); \ | |
2192 | }) | |
2193 | ||
847ce401 WF |
2194 | /** |
2195 | * unpoison_memory - Unpoison a previously poisoned page | |
2196 | * @pfn: Page number of the to be unpoisoned page | |
2197 | * | |
2198 | * Software-unpoison a page that has been poisoned by | |
2199 | * memory_failure() earlier. | |
2200 | * | |
2201 | * This is only done on the software-level, so it only works | |
2202 | * for linux injected failures, not real hardware failures | |
2203 | * | |
2204 | * Returns 0 for success, otherwise -errno. | |
2205 | */ | |
2206 | int unpoison_memory(unsigned long pfn) | |
2207 | { | |
2208 | struct page *page; | |
2209 | struct page *p; | |
bf181c58 | 2210 | int ret = -EBUSY; |
c8bd84f7 | 2211 | int freeit = 0; |
a5f65109 NH |
2212 | static DEFINE_RATELIMIT_STATE(unpoison_rs, DEFAULT_RATELIMIT_INTERVAL, |
2213 | DEFAULT_RATELIMIT_BURST); | |
847ce401 WF |
2214 | |
2215 | if (!pfn_valid(pfn)) | |
2216 | return -ENXIO; | |
2217 | ||
2218 | p = pfn_to_page(pfn); | |
2219 | page = compound_head(p); | |
2220 | ||
91d00547 NH |
2221 | mutex_lock(&mf_mutex); |
2222 | ||
67f22ba7 | 2223 | if (hw_memory_failure) { |
2224 | unpoison_pr_info("Unpoison: Disabled after HW memory failure %#lx\n", | |
2225 | pfn, &unpoison_rs); | |
2226 | ret = -EOPNOTSUPP; | |
2227 | goto unlock_mutex; | |
2228 | } | |
2229 | ||
847ce401 | 2230 | if (!PageHWPoison(p)) { |
495367c0 | 2231 | unpoison_pr_info("Unpoison: Page was already unpoisoned %#lx\n", |
a5f65109 | 2232 | pfn, &unpoison_rs); |
91d00547 | 2233 | goto unlock_mutex; |
847ce401 WF |
2234 | } |
2235 | ||
230ac719 | 2236 | if (page_count(page) > 1) { |
495367c0 | 2237 | unpoison_pr_info("Unpoison: Someone grabs the hwpoison page %#lx\n", |
a5f65109 | 2238 | pfn, &unpoison_rs); |
91d00547 | 2239 | goto unlock_mutex; |
230ac719 NH |
2240 | } |
2241 | ||
2242 | if (page_mapped(page)) { | |
495367c0 | 2243 | unpoison_pr_info("Unpoison: Someone maps the hwpoison page %#lx\n", |
a5f65109 | 2244 | pfn, &unpoison_rs); |
91d00547 | 2245 | goto unlock_mutex; |
230ac719 NH |
2246 | } |
2247 | ||
2248 | if (page_mapping(page)) { | |
495367c0 | 2249 | unpoison_pr_info("Unpoison: the hwpoison page has non-NULL mapping %#lx\n", |
a5f65109 | 2250 | pfn, &unpoison_rs); |
91d00547 | 2251 | goto unlock_mutex; |
0cea3fdc WL |
2252 | } |
2253 | ||
bf181c58 | 2254 | if (PageSlab(page) || PageTable(page)) |
91d00547 | 2255 | goto unlock_mutex; |
847ce401 | 2256 | |
bf181c58 NH |
2257 | ret = get_hwpoison_page(p, MF_UNPOISON); |
2258 | if (!ret) { | |
c8bd84f7 | 2259 | ret = TestClearPageHWPoison(page) ? 0 : -EBUSY; |
bf181c58 NH |
2260 | } else if (ret < 0) { |
2261 | if (ret == -EHWPOISON) { | |
c8bd84f7 | 2262 | ret = put_page_back_buddy(p) ? 0 : -EBUSY; |
bf181c58 NH |
2263 | } else |
2264 | unpoison_pr_info("Unpoison: failed to grab page %#lx\n", | |
2265 | pfn, &unpoison_rs); | |
2266 | } else { | |
c8bd84f7 | 2267 | freeit = !!TestClearPageHWPoison(p); |
847ce401 | 2268 | |
dd6e2402 | 2269 | put_page(page); |
bf181c58 NH |
2270 | if (freeit && !(pfn == my_zero_pfn(0) && page_count(p) == 1)) { |
2271 | put_page(page); | |
2272 | ret = 0; | |
2273 | } | |
2274 | } | |
847ce401 | 2275 | |
91d00547 NH |
2276 | unlock_mutex: |
2277 | mutex_unlock(&mf_mutex); | |
c8bd84f7 | 2278 | if (!ret || freeit) { |
2279 | num_poisoned_pages_dec(); | |
2280 | unpoison_pr_info("Unpoison: Software-unpoisoned page %#lx\n", | |
2281 | page_to_pfn(p), &unpoison_rs); | |
2282 | } | |
91d00547 | 2283 | return ret; |
847ce401 WF |
2284 | } |
2285 | EXPORT_SYMBOL(unpoison_memory); | |
facb6011 | 2286 | |
6b9a217e | 2287 | static bool isolate_page(struct page *page, struct list_head *pagelist) |
d950b958 | 2288 | { |
6b9a217e OS |
2289 | bool isolated = false; |
2290 | bool lru = PageLRU(page); | |
d950b958 | 2291 | |
6b9a217e | 2292 | if (PageHuge(page)) { |
7ce82f4c | 2293 | isolated = !isolate_hugetlb(page, pagelist); |
6b9a217e OS |
2294 | } else { |
2295 | if (lru) | |
2296 | isolated = !isolate_lru_page(page); | |
2297 | else | |
2298 | isolated = !isolate_movable_page(page, ISOLATE_UNEVICTABLE); | |
2299 | ||
2300 | if (isolated) | |
2301 | list_add(&page->lru, pagelist); | |
0ebff32c | 2302 | } |
d950b958 | 2303 | |
6b9a217e OS |
2304 | if (isolated && lru) |
2305 | inc_node_page_state(page, NR_ISOLATED_ANON + | |
2306 | page_is_file_lru(page)); | |
2307 | ||
03613808 | 2308 | /* |
6b9a217e OS |
2309 | * If we succeed to isolate the page, we grabbed another refcount on |
2310 | * the page, so we can safely drop the one we got from get_any_pages(). | |
2311 | * If we failed to isolate the page, it means that we cannot go further | |
2312 | * and we will return an error, so drop the reference we got from | |
2313 | * get_any_pages() as well. | |
03613808 | 2314 | */ |
6b9a217e OS |
2315 | put_page(page); |
2316 | return isolated; | |
d950b958 NH |
2317 | } |
2318 | ||
6b9a217e OS |
2319 | /* |
2320 | * __soft_offline_page handles hugetlb-pages and non-hugetlb pages. | |
2321 | * If the page is a non-dirty unmapped page-cache page, it simply invalidates. | |
2322 | * If the page is mapped, it migrates the contents over. | |
2323 | */ | |
2324 | static int __soft_offline_page(struct page *page) | |
af8fae7c | 2325 | { |
d6c75dc2 | 2326 | long ret = 0; |
af8fae7c | 2327 | unsigned long pfn = page_to_pfn(page); |
6b9a217e OS |
2328 | struct page *hpage = compound_head(page); |
2329 | char const *msg_page[] = {"page", "hugepage"}; | |
2330 | bool huge = PageHuge(page); | |
2331 | LIST_HEAD(pagelist); | |
54608759 JK |
2332 | struct migration_target_control mtc = { |
2333 | .nid = NUMA_NO_NODE, | |
2334 | .gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL, | |
2335 | }; | |
facb6011 | 2336 | |
0ebff32c | 2337 | lock_page(page); |
6b9a217e OS |
2338 | if (!PageHuge(page)) |
2339 | wait_on_page_writeback(page); | |
af8fae7c NH |
2340 | if (PageHWPoison(page)) { |
2341 | unlock_page(page); | |
dd6e2402 | 2342 | put_page(page); |
af8fae7c | 2343 | pr_info("soft offline: %#lx page already poisoned\n", pfn); |
5a2ffca3 | 2344 | return 0; |
af8fae7c | 2345 | } |
6b9a217e | 2346 | |
593396b8 | 2347 | if (!PageHuge(page) && PageLRU(page) && !PageSwapCache(page)) |
6b9a217e OS |
2348 | /* |
2349 | * Try to invalidate first. This should work for | |
2350 | * non dirty unmapped page cache pages. | |
2351 | */ | |
2352 | ret = invalidate_inode_page(page); | |
facb6011 | 2353 | unlock_page(page); |
6b9a217e | 2354 | |
6b9a217e | 2355 | if (ret) { |
fb46e735 | 2356 | pr_info("soft_offline: %#lx: invalidated\n", pfn); |
6b9a217e | 2357 | page_handle_poison(page, false, true); |
af8fae7c | 2358 | return 0; |
facb6011 AK |
2359 | } |
2360 | ||
6b9a217e | 2361 | if (isolate_page(hpage, &pagelist)) { |
54608759 | 2362 | ret = migrate_pages(&pagelist, alloc_migration_target, NULL, |
5ac95884 | 2363 | (unsigned long)&mtc, MIGRATE_SYNC, MR_MEMORY_FAILURE, NULL); |
79f5f8fa | 2364 | if (!ret) { |
6b9a217e OS |
2365 | bool release = !huge; |
2366 | ||
2367 | if (!page_handle_poison(page, huge, release)) | |
2368 | ret = -EBUSY; | |
79f5f8fa | 2369 | } else { |
85fbe5d1 YX |
2370 | if (!list_empty(&pagelist)) |
2371 | putback_movable_pages(&pagelist); | |
59c82b70 | 2372 | |
d6c75dc2 | 2373 | pr_info("soft offline: %#lx: %s migration failed %ld, type %pGp\n", |
23efd080 | 2374 | pfn, msg_page[huge], ret, &page->flags); |
facb6011 | 2375 | if (ret > 0) |
3f4b815a | 2376 | ret = -EBUSY; |
facb6011 AK |
2377 | } |
2378 | } else { | |
23efd080 MWO |
2379 | pr_info("soft offline: %#lx: %s isolation failed, page count %d, type %pGp\n", |
2380 | pfn, msg_page[huge], page_count(page), &page->flags); | |
6b9a217e | 2381 | ret = -EBUSY; |
facb6011 | 2382 | } |
facb6011 AK |
2383 | return ret; |
2384 | } | |
86e05773 | 2385 | |
6b9a217e | 2386 | static int soft_offline_in_use_page(struct page *page) |
acc14dc4 | 2387 | { |
acc14dc4 NH |
2388 | struct page *hpage = compound_head(page); |
2389 | ||
694bf0b0 OS |
2390 | if (!PageHuge(page) && PageTransHuge(hpage)) |
2391 | if (try_to_split_thp_page(page, "soft offline") < 0) | |
acc14dc4 | 2392 | return -EBUSY; |
6b9a217e | 2393 | return __soft_offline_page(page); |
acc14dc4 NH |
2394 | } |
2395 | ||
d4ae9916 | 2396 | static int soft_offline_free_page(struct page *page) |
acc14dc4 | 2397 | { |
6b9a217e | 2398 | int rc = 0; |
acc14dc4 | 2399 | |
6b9a217e OS |
2400 | if (!page_handle_poison(page, true, false)) |
2401 | rc = -EBUSY; | |
06be6ff3 | 2402 | |
d4ae9916 | 2403 | return rc; |
acc14dc4 NH |
2404 | } |
2405 | ||
dad4e5b3 DW |
2406 | static void put_ref_page(struct page *page) |
2407 | { | |
2408 | if (page) | |
2409 | put_page(page); | |
2410 | } | |
2411 | ||
86e05773 WL |
2412 | /** |
2413 | * soft_offline_page - Soft offline a page. | |
feec24a6 | 2414 | * @pfn: pfn to soft-offline |
86e05773 WL |
2415 | * @flags: flags. Same as memory_failure(). |
2416 | * | |
9113eaf3 | 2417 | * Returns 0 on success |
2418 | * -EOPNOTSUPP for hwpoison_filter() filtered the error event | |
2419 | * < 0 otherwise negated errno. | |
86e05773 WL |
2420 | * |
2421 | * Soft offline a page, by migration or invalidation, | |
2422 | * without killing anything. This is for the case when | |
2423 | * a page is not corrupted yet (so it's still valid to access), | |
2424 | * but has had a number of corrected errors and is better taken | |
2425 | * out. | |
2426 | * | |
2427 | * The actual policy on when to do that is maintained by | |
2428 | * user space. | |
2429 | * | |
2430 | * This should never impact any application or cause data loss, | |
2431 | * however it might take some time. | |
2432 | * | |
2433 | * This is not a 100% solution for all memory, but tries to be | |
2434 | * ``good enough'' for the majority of memory. | |
2435 | */ | |
feec24a6 | 2436 | int soft_offline_page(unsigned long pfn, int flags) |
86e05773 WL |
2437 | { |
2438 | int ret; | |
b94e0282 | 2439 | bool try_again = true; |
dad4e5b3 DW |
2440 | struct page *page, *ref_page = NULL; |
2441 | ||
2442 | WARN_ON_ONCE(!pfn_valid(pfn) && (flags & MF_COUNT_INCREASED)); | |
86e05773 | 2443 | |
feec24a6 NH |
2444 | if (!pfn_valid(pfn)) |
2445 | return -ENXIO; | |
dad4e5b3 DW |
2446 | if (flags & MF_COUNT_INCREASED) |
2447 | ref_page = pfn_to_page(pfn); | |
2448 | ||
feec24a6 NH |
2449 | /* Only online pages can be soft-offlined (esp., not ZONE_DEVICE). */ |
2450 | page = pfn_to_online_page(pfn); | |
dad4e5b3 DW |
2451 | if (!page) { |
2452 | put_ref_page(ref_page); | |
86a66810 | 2453 | return -EIO; |
dad4e5b3 | 2454 | } |
86a66810 | 2455 | |
91d00547 NH |
2456 | mutex_lock(&mf_mutex); |
2457 | ||
86e05773 | 2458 | if (PageHWPoison(page)) { |
8295d535 | 2459 | pr_info("%s: %#lx page already poisoned\n", __func__, pfn); |
dad4e5b3 | 2460 | put_ref_page(ref_page); |
91d00547 | 2461 | mutex_unlock(&mf_mutex); |
5a2ffca3 | 2462 | return 0; |
86e05773 | 2463 | } |
86e05773 | 2464 | |
b94e0282 | 2465 | retry: |
bfc8c901 | 2466 | get_online_mems(); |
bf6445bc | 2467 | ret = get_hwpoison_page(page, flags | MF_SOFT_OFFLINE); |
bfc8c901 | 2468 | put_online_mems(); |
4e41a30c | 2469 | |
9113eaf3 | 2470 | if (hwpoison_filter(page)) { |
2471 | if (ret > 0) | |
2472 | put_page(page); | |
2473 | else | |
2474 | put_ref_page(ref_page); | |
2475 | ||
2476 | mutex_unlock(&mf_mutex); | |
2477 | return -EOPNOTSUPP; | |
2478 | } | |
2479 | ||
8295d535 | 2480 | if (ret > 0) { |
6b9a217e | 2481 | ret = soft_offline_in_use_page(page); |
8295d535 | 2482 | } else if (ret == 0) { |
b94e0282 OS |
2483 | if (soft_offline_free_page(page) && try_again) { |
2484 | try_again = false; | |
2a57d83c | 2485 | flags &= ~MF_COUNT_INCREASED; |
b94e0282 OS |
2486 | goto retry; |
2487 | } | |
8295d535 | 2488 | } |
4e41a30c | 2489 | |
91d00547 NH |
2490 | mutex_unlock(&mf_mutex); |
2491 | ||
86e05773 WL |
2492 | return ret; |
2493 | } | |
60f272f6 | 2494 | |
2495 | void clear_hwpoisoned_pages(struct page *memmap, int nr_pages) | |
2496 | { | |
2497 | int i; | |
2498 | ||
2499 | /* | |
2500 | * A further optimization is to have per section refcounted | |
2501 | * num_poisoned_pages. But that would need more space per memmap, so | |
2502 | * for now just do a quick global check to speed up this routine in the | |
2503 | * absence of bad pages. | |
2504 | */ | |
2505 | if (atomic_long_read(&num_poisoned_pages) == 0) | |
2506 | return; | |
2507 | ||
2508 | for (i = 0; i < nr_pages; i++) { | |
2509 | if (PageHWPoison(&memmap[i])) { | |
2510 | num_poisoned_pages_dec(); | |
2511 | ClearPageHWPoison(&memmap[i]); | |
2512 | } | |
2513 | } | |
2514 | } |