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6a46079c AK |
1 | /* |
2 | * Copyright (C) 2008, 2009 Intel Corporation | |
3 | * Authors: Andi Kleen, Fengguang Wu | |
4 | * | |
5 | * This software may be redistributed and/or modified under the terms of | |
6 | * the GNU General Public License ("GPL") version 2 only as published by the | |
7 | * Free Software Foundation. | |
8 | * | |
9 | * High level machine check handler. Handles pages reported by the | |
1c80b990 | 10 | * hardware as being corrupted usually due to a multi-bit ECC memory or cache |
6a46079c | 11 | * failure. |
1c80b990 AK |
12 | * |
13 | * In addition there is a "soft offline" entry point that allows stop using | |
14 | * not-yet-corrupted-by-suspicious pages without killing anything. | |
6a46079c AK |
15 | * |
16 | * Handles page cache pages in various states. The tricky part | |
1c80b990 AK |
17 | * here is that we can access any page asynchronously in respect to |
18 | * other VM users, because memory failures could happen anytime and | |
19 | * anywhere. This could violate some of their assumptions. This is why | |
20 | * this code has to be extremely careful. Generally it tries to use | |
21 | * normal locking rules, as in get the standard locks, even if that means | |
22 | * the error handling takes potentially a long time. | |
23 | * | |
24 | * There are several operations here with exponential complexity because | |
25 | * of unsuitable VM data structures. For example the operation to map back | |
26 | * from RMAP chains to processes has to walk the complete process list and | |
27 | * has non linear complexity with the number. But since memory corruptions | |
28 | * are rare we hope to get away with this. This avoids impacting the core | |
29 | * VM. | |
6a46079c AK |
30 | */ |
31 | ||
32 | /* | |
33 | * Notebook: | |
34 | * - hugetlb needs more code | |
35 | * - kcore/oldmem/vmcore/mem/kmem check for hwpoison pages | |
36 | * - pass bad pages to kdump next kernel | |
37 | */ | |
6a46079c AK |
38 | #include <linux/kernel.h> |
39 | #include <linux/mm.h> | |
40 | #include <linux/page-flags.h> | |
478c5ffc | 41 | #include <linux/kernel-page-flags.h> |
6a46079c | 42 | #include <linux/sched.h> |
01e00f88 | 43 | #include <linux/ksm.h> |
6a46079c | 44 | #include <linux/rmap.h> |
b9e15baf | 45 | #include <linux/export.h> |
6a46079c AK |
46 | #include <linux/pagemap.h> |
47 | #include <linux/swap.h> | |
48 | #include <linux/backing-dev.h> | |
facb6011 AK |
49 | #include <linux/migrate.h> |
50 | #include <linux/page-isolation.h> | |
51 | #include <linux/suspend.h> | |
5a0e3ad6 | 52 | #include <linux/slab.h> |
bf998156 | 53 | #include <linux/swapops.h> |
7af446a8 | 54 | #include <linux/hugetlb.h> |
20d6c96b | 55 | #include <linux/memory_hotplug.h> |
5db8a73a | 56 | #include <linux/mm_inline.h> |
ea8f5fb8 | 57 | #include <linux/kfifo.h> |
6a46079c AK |
58 | #include "internal.h" |
59 | ||
60 | int sysctl_memory_failure_early_kill __read_mostly = 0; | |
61 | ||
62 | int sysctl_memory_failure_recovery __read_mostly = 1; | |
63 | ||
293c07e3 | 64 | atomic_long_t num_poisoned_pages __read_mostly = ATOMIC_LONG_INIT(0); |
6a46079c | 65 | |
27df5068 AK |
66 | #if defined(CONFIG_HWPOISON_INJECT) || defined(CONFIG_HWPOISON_INJECT_MODULE) |
67 | ||
1bfe5feb | 68 | u32 hwpoison_filter_enable = 0; |
7c116f2b WF |
69 | u32 hwpoison_filter_dev_major = ~0U; |
70 | u32 hwpoison_filter_dev_minor = ~0U; | |
478c5ffc WF |
71 | u64 hwpoison_filter_flags_mask; |
72 | u64 hwpoison_filter_flags_value; | |
1bfe5feb | 73 | EXPORT_SYMBOL_GPL(hwpoison_filter_enable); |
7c116f2b WF |
74 | EXPORT_SYMBOL_GPL(hwpoison_filter_dev_major); |
75 | EXPORT_SYMBOL_GPL(hwpoison_filter_dev_minor); | |
478c5ffc WF |
76 | EXPORT_SYMBOL_GPL(hwpoison_filter_flags_mask); |
77 | EXPORT_SYMBOL_GPL(hwpoison_filter_flags_value); | |
7c116f2b WF |
78 | |
79 | static int hwpoison_filter_dev(struct page *p) | |
80 | { | |
81 | struct address_space *mapping; | |
82 | dev_t dev; | |
83 | ||
84 | if (hwpoison_filter_dev_major == ~0U && | |
85 | hwpoison_filter_dev_minor == ~0U) | |
86 | return 0; | |
87 | ||
88 | /* | |
1c80b990 | 89 | * page_mapping() does not accept slab pages. |
7c116f2b WF |
90 | */ |
91 | if (PageSlab(p)) | |
92 | return -EINVAL; | |
93 | ||
94 | mapping = page_mapping(p); | |
95 | if (mapping == NULL || mapping->host == NULL) | |
96 | return -EINVAL; | |
97 | ||
98 | dev = mapping->host->i_sb->s_dev; | |
99 | if (hwpoison_filter_dev_major != ~0U && | |
100 | hwpoison_filter_dev_major != MAJOR(dev)) | |
101 | return -EINVAL; | |
102 | if (hwpoison_filter_dev_minor != ~0U && | |
103 | hwpoison_filter_dev_minor != MINOR(dev)) | |
104 | return -EINVAL; | |
105 | ||
106 | return 0; | |
107 | } | |
108 | ||
478c5ffc WF |
109 | static int hwpoison_filter_flags(struct page *p) |
110 | { | |
111 | if (!hwpoison_filter_flags_mask) | |
112 | return 0; | |
113 | ||
114 | if ((stable_page_flags(p) & hwpoison_filter_flags_mask) == | |
115 | hwpoison_filter_flags_value) | |
116 | return 0; | |
117 | else | |
118 | return -EINVAL; | |
119 | } | |
120 | ||
4fd466eb AK |
121 | /* |
122 | * This allows stress tests to limit test scope to a collection of tasks | |
123 | * by putting them under some memcg. This prevents killing unrelated/important | |
124 | * processes such as /sbin/init. Note that the target task may share clean | |
125 | * pages with init (eg. libc text), which is harmless. If the target task | |
126 | * share _dirty_ pages with another task B, the test scheme must make sure B | |
127 | * is also included in the memcg. At last, due to race conditions this filter | |
128 | * can only guarantee that the page either belongs to the memcg tasks, or is | |
129 | * a freed page. | |
130 | */ | |
c255a458 | 131 | #ifdef CONFIG_MEMCG_SWAP |
4fd466eb AK |
132 | u64 hwpoison_filter_memcg; |
133 | EXPORT_SYMBOL_GPL(hwpoison_filter_memcg); | |
134 | static int hwpoison_filter_task(struct page *p) | |
135 | { | |
136 | struct mem_cgroup *mem; | |
137 | struct cgroup_subsys_state *css; | |
138 | unsigned long ino; | |
139 | ||
140 | if (!hwpoison_filter_memcg) | |
141 | return 0; | |
142 | ||
143 | mem = try_get_mem_cgroup_from_page(p); | |
144 | if (!mem) | |
145 | return -EINVAL; | |
146 | ||
147 | css = mem_cgroup_css(mem); | |
b1664924 | 148 | ino = cgroup_ino(css->cgroup); |
4fd466eb AK |
149 | css_put(css); |
150 | ||
f29374b1 | 151 | if (ino != hwpoison_filter_memcg) |
4fd466eb AK |
152 | return -EINVAL; |
153 | ||
154 | return 0; | |
155 | } | |
156 | #else | |
157 | static int hwpoison_filter_task(struct page *p) { return 0; } | |
158 | #endif | |
159 | ||
7c116f2b WF |
160 | int hwpoison_filter(struct page *p) |
161 | { | |
1bfe5feb HL |
162 | if (!hwpoison_filter_enable) |
163 | return 0; | |
164 | ||
7c116f2b WF |
165 | if (hwpoison_filter_dev(p)) |
166 | return -EINVAL; | |
167 | ||
478c5ffc WF |
168 | if (hwpoison_filter_flags(p)) |
169 | return -EINVAL; | |
170 | ||
4fd466eb AK |
171 | if (hwpoison_filter_task(p)) |
172 | return -EINVAL; | |
173 | ||
7c116f2b WF |
174 | return 0; |
175 | } | |
27df5068 AK |
176 | #else |
177 | int hwpoison_filter(struct page *p) | |
178 | { | |
179 | return 0; | |
180 | } | |
181 | #endif | |
182 | ||
7c116f2b WF |
183 | EXPORT_SYMBOL_GPL(hwpoison_filter); |
184 | ||
6a46079c | 185 | /* |
7329bbeb TL |
186 | * Send all the processes who have the page mapped a signal. |
187 | * ``action optional'' if they are not immediately affected by the error | |
188 | * ``action required'' if error happened in current execution context | |
6a46079c | 189 | */ |
7329bbeb TL |
190 | static int kill_proc(struct task_struct *t, unsigned long addr, int trapno, |
191 | unsigned long pfn, struct page *page, int flags) | |
6a46079c AK |
192 | { |
193 | struct siginfo si; | |
194 | int ret; | |
195 | ||
196 | printk(KERN_ERR | |
7329bbeb | 197 | "MCE %#lx: Killing %s:%d due to hardware memory corruption\n", |
6a46079c AK |
198 | pfn, t->comm, t->pid); |
199 | si.si_signo = SIGBUS; | |
200 | si.si_errno = 0; | |
6a46079c AK |
201 | si.si_addr = (void *)addr; |
202 | #ifdef __ARCH_SI_TRAPNO | |
203 | si.si_trapno = trapno; | |
204 | #endif | |
f9121153 | 205 | si.si_addr_lsb = compound_order(compound_head(page)) + PAGE_SHIFT; |
7329bbeb | 206 | |
a70ffcac | 207 | if ((flags & MF_ACTION_REQUIRED) && t->mm == current->mm) { |
7329bbeb | 208 | si.si_code = BUS_MCEERR_AR; |
a70ffcac | 209 | ret = force_sig_info(SIGBUS, &si, current); |
7329bbeb TL |
210 | } else { |
211 | /* | |
212 | * Don't use force here, it's convenient if the signal | |
213 | * can be temporarily blocked. | |
214 | * This could cause a loop when the user sets SIGBUS | |
215 | * to SIG_IGN, but hopefully no one will do that? | |
216 | */ | |
217 | si.si_code = BUS_MCEERR_AO; | |
218 | ret = send_sig_info(SIGBUS, &si, t); /* synchronous? */ | |
219 | } | |
6a46079c AK |
220 | if (ret < 0) |
221 | printk(KERN_INFO "MCE: Error sending signal to %s:%d: %d\n", | |
222 | t->comm, t->pid, ret); | |
223 | return ret; | |
224 | } | |
225 | ||
588f9ce6 AK |
226 | /* |
227 | * When a unknown page type is encountered drain as many buffers as possible | |
228 | * in the hope to turn the page into a LRU or free page, which we can handle. | |
229 | */ | |
facb6011 | 230 | void shake_page(struct page *p, int access) |
588f9ce6 AK |
231 | { |
232 | if (!PageSlab(p)) { | |
233 | lru_add_drain_all(); | |
234 | if (PageLRU(p)) | |
235 | return; | |
c0554329 | 236 | drain_all_pages(page_zone(p)); |
588f9ce6 AK |
237 | if (PageLRU(p) || is_free_buddy_page(p)) |
238 | return; | |
239 | } | |
facb6011 | 240 | |
588f9ce6 | 241 | /* |
6b4f7799 JW |
242 | * Only call shrink_node_slabs here (which would also shrink |
243 | * other caches) if access is not potentially fatal. | |
588f9ce6 | 244 | */ |
facb6011 AK |
245 | if (access) { |
246 | int nr; | |
0ce3d744 | 247 | int nid = page_to_nid(p); |
facb6011 | 248 | do { |
6b4f7799 | 249 | nr = shrink_node_slabs(GFP_KERNEL, nid, 1000, 1000); |
47f43e7e | 250 | if (page_count(p) == 1) |
facb6011 AK |
251 | break; |
252 | } while (nr > 10); | |
253 | } | |
588f9ce6 AK |
254 | } |
255 | EXPORT_SYMBOL_GPL(shake_page); | |
256 | ||
6a46079c AK |
257 | /* |
258 | * Kill all processes that have a poisoned page mapped and then isolate | |
259 | * the page. | |
260 | * | |
261 | * General strategy: | |
262 | * Find all processes having the page mapped and kill them. | |
263 | * But we keep a page reference around so that the page is not | |
264 | * actually freed yet. | |
265 | * Then stash the page away | |
266 | * | |
267 | * There's no convenient way to get back to mapped processes | |
268 | * from the VMAs. So do a brute-force search over all | |
269 | * running processes. | |
270 | * | |
271 | * Remember that machine checks are not common (or rather | |
272 | * if they are common you have other problems), so this shouldn't | |
273 | * be a performance issue. | |
274 | * | |
275 | * Also there are some races possible while we get from the | |
276 | * error detection to actually handle it. | |
277 | */ | |
278 | ||
279 | struct to_kill { | |
280 | struct list_head nd; | |
281 | struct task_struct *tsk; | |
282 | unsigned long addr; | |
9033ae16 | 283 | char addr_valid; |
6a46079c AK |
284 | }; |
285 | ||
286 | /* | |
287 | * Failure handling: if we can't find or can't kill a process there's | |
288 | * not much we can do. We just print a message and ignore otherwise. | |
289 | */ | |
290 | ||
291 | /* | |
292 | * Schedule a process for later kill. | |
293 | * Uses GFP_ATOMIC allocations to avoid potential recursions in the VM. | |
294 | * TBD would GFP_NOIO be enough? | |
295 | */ | |
296 | static void add_to_kill(struct task_struct *tsk, struct page *p, | |
297 | struct vm_area_struct *vma, | |
298 | struct list_head *to_kill, | |
299 | struct to_kill **tkc) | |
300 | { | |
301 | struct to_kill *tk; | |
302 | ||
303 | if (*tkc) { | |
304 | tk = *tkc; | |
305 | *tkc = NULL; | |
306 | } else { | |
307 | tk = kmalloc(sizeof(struct to_kill), GFP_ATOMIC); | |
308 | if (!tk) { | |
309 | printk(KERN_ERR | |
310 | "MCE: Out of memory while machine check handling\n"); | |
311 | return; | |
312 | } | |
313 | } | |
314 | tk->addr = page_address_in_vma(p, vma); | |
315 | tk->addr_valid = 1; | |
316 | ||
317 | /* | |
318 | * In theory we don't have to kill when the page was | |
319 | * munmaped. But it could be also a mremap. Since that's | |
320 | * likely very rare kill anyways just out of paranoia, but use | |
321 | * a SIGKILL because the error is not contained anymore. | |
322 | */ | |
323 | if (tk->addr == -EFAULT) { | |
fb46e735 | 324 | pr_info("MCE: Unable to find user space address %lx in %s\n", |
6a46079c AK |
325 | page_to_pfn(p), tsk->comm); |
326 | tk->addr_valid = 0; | |
327 | } | |
328 | get_task_struct(tsk); | |
329 | tk->tsk = tsk; | |
330 | list_add_tail(&tk->nd, to_kill); | |
331 | } | |
332 | ||
333 | /* | |
334 | * Kill the processes that have been collected earlier. | |
335 | * | |
336 | * Only do anything when DOIT is set, otherwise just free the list | |
337 | * (this is used for clean pages which do not need killing) | |
338 | * Also when FAIL is set do a force kill because something went | |
339 | * wrong earlier. | |
340 | */ | |
6751ed65 | 341 | static void kill_procs(struct list_head *to_kill, int forcekill, int trapno, |
7329bbeb TL |
342 | int fail, struct page *page, unsigned long pfn, |
343 | int flags) | |
6a46079c AK |
344 | { |
345 | struct to_kill *tk, *next; | |
346 | ||
347 | list_for_each_entry_safe (tk, next, to_kill, nd) { | |
6751ed65 | 348 | if (forcekill) { |
6a46079c | 349 | /* |
af901ca1 | 350 | * In case something went wrong with munmapping |
6a46079c AK |
351 | * make sure the process doesn't catch the |
352 | * signal and then access the memory. Just kill it. | |
6a46079c AK |
353 | */ |
354 | if (fail || tk->addr_valid == 0) { | |
355 | printk(KERN_ERR | |
356 | "MCE %#lx: forcibly killing %s:%d because of failure to unmap corrupted page\n", | |
357 | pfn, tk->tsk->comm, tk->tsk->pid); | |
358 | force_sig(SIGKILL, tk->tsk); | |
359 | } | |
360 | ||
361 | /* | |
362 | * In theory the process could have mapped | |
363 | * something else on the address in-between. We could | |
364 | * check for that, but we need to tell the | |
365 | * process anyways. | |
366 | */ | |
7329bbeb TL |
367 | else if (kill_proc(tk->tsk, tk->addr, trapno, |
368 | pfn, page, flags) < 0) | |
6a46079c AK |
369 | printk(KERN_ERR |
370 | "MCE %#lx: Cannot send advisory machine check signal to %s:%d\n", | |
371 | pfn, tk->tsk->comm, tk->tsk->pid); | |
372 | } | |
373 | put_task_struct(tk->tsk); | |
374 | kfree(tk); | |
375 | } | |
376 | } | |
377 | ||
3ba08129 NH |
378 | /* |
379 | * Find a dedicated thread which is supposed to handle SIGBUS(BUS_MCEERR_AO) | |
380 | * on behalf of the thread group. Return task_struct of the (first found) | |
381 | * dedicated thread if found, and return NULL otherwise. | |
382 | * | |
383 | * We already hold read_lock(&tasklist_lock) in the caller, so we don't | |
384 | * have to call rcu_read_lock/unlock() in this function. | |
385 | */ | |
386 | static struct task_struct *find_early_kill_thread(struct task_struct *tsk) | |
6a46079c | 387 | { |
3ba08129 NH |
388 | struct task_struct *t; |
389 | ||
390 | for_each_thread(tsk, t) | |
391 | if ((t->flags & PF_MCE_PROCESS) && (t->flags & PF_MCE_EARLY)) | |
392 | return t; | |
393 | return NULL; | |
394 | } | |
395 | ||
396 | /* | |
397 | * Determine whether a given process is "early kill" process which expects | |
398 | * to be signaled when some page under the process is hwpoisoned. | |
399 | * Return task_struct of the dedicated thread (main thread unless explicitly | |
400 | * specified) if the process is "early kill," and otherwise returns NULL. | |
401 | */ | |
402 | static struct task_struct *task_early_kill(struct task_struct *tsk, | |
403 | int force_early) | |
404 | { | |
405 | struct task_struct *t; | |
6a46079c | 406 | if (!tsk->mm) |
3ba08129 | 407 | return NULL; |
74614de1 | 408 | if (force_early) |
3ba08129 NH |
409 | return tsk; |
410 | t = find_early_kill_thread(tsk); | |
411 | if (t) | |
412 | return t; | |
413 | if (sysctl_memory_failure_early_kill) | |
414 | return tsk; | |
415 | return NULL; | |
6a46079c AK |
416 | } |
417 | ||
418 | /* | |
419 | * Collect processes when the error hit an anonymous page. | |
420 | */ | |
421 | static void collect_procs_anon(struct page *page, struct list_head *to_kill, | |
74614de1 | 422 | struct to_kill **tkc, int force_early) |
6a46079c AK |
423 | { |
424 | struct vm_area_struct *vma; | |
425 | struct task_struct *tsk; | |
426 | struct anon_vma *av; | |
bf181b9f | 427 | pgoff_t pgoff; |
6a46079c | 428 | |
4fc3f1d6 | 429 | av = page_lock_anon_vma_read(page); |
6a46079c | 430 | if (av == NULL) /* Not actually mapped anymore */ |
9b679320 PZ |
431 | return; |
432 | ||
a0f7a756 | 433 | pgoff = page_to_pgoff(page); |
9b679320 | 434 | read_lock(&tasklist_lock); |
6a46079c | 435 | for_each_process (tsk) { |
5beb4930 | 436 | struct anon_vma_chain *vmac; |
3ba08129 | 437 | struct task_struct *t = task_early_kill(tsk, force_early); |
5beb4930 | 438 | |
3ba08129 | 439 | if (!t) |
6a46079c | 440 | continue; |
bf181b9f ML |
441 | anon_vma_interval_tree_foreach(vmac, &av->rb_root, |
442 | pgoff, pgoff) { | |
5beb4930 | 443 | vma = vmac->vma; |
6a46079c AK |
444 | if (!page_mapped_in_vma(page, vma)) |
445 | continue; | |
3ba08129 NH |
446 | if (vma->vm_mm == t->mm) |
447 | add_to_kill(t, page, vma, to_kill, tkc); | |
6a46079c AK |
448 | } |
449 | } | |
6a46079c | 450 | read_unlock(&tasklist_lock); |
4fc3f1d6 | 451 | page_unlock_anon_vma_read(av); |
6a46079c AK |
452 | } |
453 | ||
454 | /* | |
455 | * Collect processes when the error hit a file mapped page. | |
456 | */ | |
457 | static void collect_procs_file(struct page *page, struct list_head *to_kill, | |
74614de1 | 458 | struct to_kill **tkc, int force_early) |
6a46079c AK |
459 | { |
460 | struct vm_area_struct *vma; | |
461 | struct task_struct *tsk; | |
6a46079c AK |
462 | struct address_space *mapping = page->mapping; |
463 | ||
d28eb9c8 | 464 | i_mmap_lock_read(mapping); |
9b679320 | 465 | read_lock(&tasklist_lock); |
6a46079c | 466 | for_each_process(tsk) { |
a0f7a756 | 467 | pgoff_t pgoff = page_to_pgoff(page); |
3ba08129 | 468 | struct task_struct *t = task_early_kill(tsk, force_early); |
6a46079c | 469 | |
3ba08129 | 470 | if (!t) |
6a46079c | 471 | continue; |
6b2dbba8 | 472 | vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, |
6a46079c AK |
473 | pgoff) { |
474 | /* | |
475 | * Send early kill signal to tasks where a vma covers | |
476 | * the page but the corrupted page is not necessarily | |
477 | * mapped it in its pte. | |
478 | * Assume applications who requested early kill want | |
479 | * to be informed of all such data corruptions. | |
480 | */ | |
3ba08129 NH |
481 | if (vma->vm_mm == t->mm) |
482 | add_to_kill(t, page, vma, to_kill, tkc); | |
6a46079c AK |
483 | } |
484 | } | |
6a46079c | 485 | read_unlock(&tasklist_lock); |
d28eb9c8 | 486 | i_mmap_unlock_read(mapping); |
6a46079c AK |
487 | } |
488 | ||
489 | /* | |
490 | * Collect the processes who have the corrupted page mapped to kill. | |
491 | * This is done in two steps for locking reasons. | |
492 | * First preallocate one tokill structure outside the spin locks, | |
493 | * so that we can kill at least one process reasonably reliable. | |
494 | */ | |
74614de1 TL |
495 | static void collect_procs(struct page *page, struct list_head *tokill, |
496 | int force_early) | |
6a46079c AK |
497 | { |
498 | struct to_kill *tk; | |
499 | ||
500 | if (!page->mapping) | |
501 | return; | |
502 | ||
503 | tk = kmalloc(sizeof(struct to_kill), GFP_NOIO); | |
504 | if (!tk) | |
505 | return; | |
506 | if (PageAnon(page)) | |
74614de1 | 507 | collect_procs_anon(page, tokill, &tk, force_early); |
6a46079c | 508 | else |
74614de1 | 509 | collect_procs_file(page, tokill, &tk, force_early); |
6a46079c AK |
510 | kfree(tk); |
511 | } | |
512 | ||
513 | /* | |
514 | * Error handlers for various types of pages. | |
515 | */ | |
516 | ||
517 | enum outcome { | |
d95ea51e WF |
518 | IGNORED, /* Error: cannot be handled */ |
519 | FAILED, /* Error: handling failed */ | |
6a46079c | 520 | DELAYED, /* Will be handled later */ |
6a46079c AK |
521 | RECOVERED, /* Successfully recovered */ |
522 | }; | |
523 | ||
524 | static const char *action_name[] = { | |
d95ea51e | 525 | [IGNORED] = "Ignored", |
6a46079c AK |
526 | [FAILED] = "Failed", |
527 | [DELAYED] = "Delayed", | |
6a46079c AK |
528 | [RECOVERED] = "Recovered", |
529 | }; | |
530 | ||
dc2a1cbf WF |
531 | /* |
532 | * XXX: It is possible that a page is isolated from LRU cache, | |
533 | * and then kept in swap cache or failed to remove from page cache. | |
534 | * The page count will stop it from being freed by unpoison. | |
535 | * Stress tests should be aware of this memory leak problem. | |
536 | */ | |
537 | static int delete_from_lru_cache(struct page *p) | |
538 | { | |
539 | if (!isolate_lru_page(p)) { | |
540 | /* | |
541 | * Clear sensible page flags, so that the buddy system won't | |
542 | * complain when the page is unpoison-and-freed. | |
543 | */ | |
544 | ClearPageActive(p); | |
545 | ClearPageUnevictable(p); | |
546 | /* | |
547 | * drop the page count elevated by isolate_lru_page() | |
548 | */ | |
549 | page_cache_release(p); | |
550 | return 0; | |
551 | } | |
552 | return -EIO; | |
553 | } | |
554 | ||
6a46079c AK |
555 | /* |
556 | * Error hit kernel page. | |
557 | * Do nothing, try to be lucky and not touch this instead. For a few cases we | |
558 | * could be more sophisticated. | |
559 | */ | |
560 | static int me_kernel(struct page *p, unsigned long pfn) | |
6a46079c AK |
561 | { |
562 | return IGNORED; | |
563 | } | |
564 | ||
565 | /* | |
566 | * Page in unknown state. Do nothing. | |
567 | */ | |
568 | static int me_unknown(struct page *p, unsigned long pfn) | |
569 | { | |
570 | printk(KERN_ERR "MCE %#lx: Unknown page state\n", pfn); | |
571 | return FAILED; | |
572 | } | |
573 | ||
6a46079c AK |
574 | /* |
575 | * Clean (or cleaned) page cache page. | |
576 | */ | |
577 | static int me_pagecache_clean(struct page *p, unsigned long pfn) | |
578 | { | |
579 | int err; | |
580 | int ret = FAILED; | |
581 | struct address_space *mapping; | |
582 | ||
dc2a1cbf WF |
583 | delete_from_lru_cache(p); |
584 | ||
6a46079c AK |
585 | /* |
586 | * For anonymous pages we're done the only reference left | |
587 | * should be the one m_f() holds. | |
588 | */ | |
589 | if (PageAnon(p)) | |
590 | return RECOVERED; | |
591 | ||
592 | /* | |
593 | * Now truncate the page in the page cache. This is really | |
594 | * more like a "temporary hole punch" | |
595 | * Don't do this for block devices when someone else | |
596 | * has a reference, because it could be file system metadata | |
597 | * and that's not safe to truncate. | |
598 | */ | |
599 | mapping = page_mapping(p); | |
600 | if (!mapping) { | |
601 | /* | |
602 | * Page has been teared down in the meanwhile | |
603 | */ | |
604 | return FAILED; | |
605 | } | |
606 | ||
607 | /* | |
608 | * Truncation is a bit tricky. Enable it per file system for now. | |
609 | * | |
610 | * Open: to take i_mutex or not for this? Right now we don't. | |
611 | */ | |
612 | if (mapping->a_ops->error_remove_page) { | |
613 | err = mapping->a_ops->error_remove_page(mapping, p); | |
614 | if (err != 0) { | |
615 | printk(KERN_INFO "MCE %#lx: Failed to punch page: %d\n", | |
616 | pfn, err); | |
617 | } else if (page_has_private(p) && | |
618 | !try_to_release_page(p, GFP_NOIO)) { | |
fb46e735 | 619 | pr_info("MCE %#lx: failed to release buffers\n", pfn); |
6a46079c AK |
620 | } else { |
621 | ret = RECOVERED; | |
622 | } | |
623 | } else { | |
624 | /* | |
625 | * If the file system doesn't support it just invalidate | |
626 | * This fails on dirty or anything with private pages | |
627 | */ | |
628 | if (invalidate_inode_page(p)) | |
629 | ret = RECOVERED; | |
630 | else | |
631 | printk(KERN_INFO "MCE %#lx: Failed to invalidate\n", | |
632 | pfn); | |
633 | } | |
634 | return ret; | |
635 | } | |
636 | ||
637 | /* | |
549543df | 638 | * Dirty pagecache page |
6a46079c AK |
639 | * Issues: when the error hit a hole page the error is not properly |
640 | * propagated. | |
641 | */ | |
642 | static int me_pagecache_dirty(struct page *p, unsigned long pfn) | |
643 | { | |
644 | struct address_space *mapping = page_mapping(p); | |
645 | ||
646 | SetPageError(p); | |
647 | /* TBD: print more information about the file. */ | |
648 | if (mapping) { | |
649 | /* | |
650 | * IO error will be reported by write(), fsync(), etc. | |
651 | * who check the mapping. | |
652 | * This way the application knows that something went | |
653 | * wrong with its dirty file data. | |
654 | * | |
655 | * There's one open issue: | |
656 | * | |
657 | * The EIO will be only reported on the next IO | |
658 | * operation and then cleared through the IO map. | |
659 | * Normally Linux has two mechanisms to pass IO error | |
660 | * first through the AS_EIO flag in the address space | |
661 | * and then through the PageError flag in the page. | |
662 | * Since we drop pages on memory failure handling the | |
663 | * only mechanism open to use is through AS_AIO. | |
664 | * | |
665 | * This has the disadvantage that it gets cleared on | |
666 | * the first operation that returns an error, while | |
667 | * the PageError bit is more sticky and only cleared | |
668 | * when the page is reread or dropped. If an | |
669 | * application assumes it will always get error on | |
670 | * fsync, but does other operations on the fd before | |
25985edc | 671 | * and the page is dropped between then the error |
6a46079c AK |
672 | * will not be properly reported. |
673 | * | |
674 | * This can already happen even without hwpoisoned | |
675 | * pages: first on metadata IO errors (which only | |
676 | * report through AS_EIO) or when the page is dropped | |
677 | * at the wrong time. | |
678 | * | |
679 | * So right now we assume that the application DTRT on | |
680 | * the first EIO, but we're not worse than other parts | |
681 | * of the kernel. | |
682 | */ | |
683 | mapping_set_error(mapping, EIO); | |
684 | } | |
685 | ||
686 | return me_pagecache_clean(p, pfn); | |
687 | } | |
688 | ||
689 | /* | |
690 | * Clean and dirty swap cache. | |
691 | * | |
692 | * Dirty swap cache page is tricky to handle. The page could live both in page | |
693 | * cache and swap cache(ie. page is freshly swapped in). So it could be | |
694 | * referenced concurrently by 2 types of PTEs: | |
695 | * normal PTEs and swap PTEs. We try to handle them consistently by calling | |
696 | * try_to_unmap(TTU_IGNORE_HWPOISON) to convert the normal PTEs to swap PTEs, | |
697 | * and then | |
698 | * - clear dirty bit to prevent IO | |
699 | * - remove from LRU | |
700 | * - but keep in the swap cache, so that when we return to it on | |
701 | * a later page fault, we know the application is accessing | |
702 | * corrupted data and shall be killed (we installed simple | |
703 | * interception code in do_swap_page to catch it). | |
704 | * | |
705 | * Clean swap cache pages can be directly isolated. A later page fault will | |
706 | * bring in the known good data from disk. | |
707 | */ | |
708 | static int me_swapcache_dirty(struct page *p, unsigned long pfn) | |
709 | { | |
6a46079c AK |
710 | ClearPageDirty(p); |
711 | /* Trigger EIO in shmem: */ | |
712 | ClearPageUptodate(p); | |
713 | ||
dc2a1cbf WF |
714 | if (!delete_from_lru_cache(p)) |
715 | return DELAYED; | |
716 | else | |
717 | return FAILED; | |
6a46079c AK |
718 | } |
719 | ||
720 | static int me_swapcache_clean(struct page *p, unsigned long pfn) | |
721 | { | |
6a46079c | 722 | delete_from_swap_cache(p); |
e43c3afb | 723 | |
dc2a1cbf WF |
724 | if (!delete_from_lru_cache(p)) |
725 | return RECOVERED; | |
726 | else | |
727 | return FAILED; | |
6a46079c AK |
728 | } |
729 | ||
730 | /* | |
731 | * Huge pages. Needs work. | |
732 | * Issues: | |
93f70f90 NH |
733 | * - Error on hugepage is contained in hugepage unit (not in raw page unit.) |
734 | * To narrow down kill region to one page, we need to break up pmd. | |
6a46079c AK |
735 | */ |
736 | static int me_huge_page(struct page *p, unsigned long pfn) | |
737 | { | |
6de2b1aa | 738 | int res = 0; |
93f70f90 NH |
739 | struct page *hpage = compound_head(p); |
740 | /* | |
741 | * We can safely recover from error on free or reserved (i.e. | |
742 | * not in-use) hugepage by dequeuing it from freelist. | |
743 | * To check whether a hugepage is in-use or not, we can't use | |
744 | * page->lru because it can be used in other hugepage operations, | |
745 | * such as __unmap_hugepage_range() and gather_surplus_pages(). | |
746 | * So instead we use page_mapping() and PageAnon(). | |
747 | * We assume that this function is called with page lock held, | |
748 | * so there is no race between isolation and mapping/unmapping. | |
749 | */ | |
750 | if (!(page_mapping(hpage) || PageAnon(hpage))) { | |
6de2b1aa NH |
751 | res = dequeue_hwpoisoned_huge_page(hpage); |
752 | if (!res) | |
753 | return RECOVERED; | |
93f70f90 NH |
754 | } |
755 | return DELAYED; | |
6a46079c AK |
756 | } |
757 | ||
758 | /* | |
759 | * Various page states we can handle. | |
760 | * | |
761 | * A page state is defined by its current page->flags bits. | |
762 | * The table matches them in order and calls the right handler. | |
763 | * | |
764 | * This is quite tricky because we can access page at any time | |
25985edc | 765 | * in its live cycle, so all accesses have to be extremely careful. |
6a46079c AK |
766 | * |
767 | * This is not complete. More states could be added. | |
768 | * For any missing state don't attempt recovery. | |
769 | */ | |
770 | ||
771 | #define dirty (1UL << PG_dirty) | |
772 | #define sc (1UL << PG_swapcache) | |
773 | #define unevict (1UL << PG_unevictable) | |
774 | #define mlock (1UL << PG_mlocked) | |
775 | #define writeback (1UL << PG_writeback) | |
776 | #define lru (1UL << PG_lru) | |
777 | #define swapbacked (1UL << PG_swapbacked) | |
778 | #define head (1UL << PG_head) | |
779 | #define tail (1UL << PG_tail) | |
780 | #define compound (1UL << PG_compound) | |
781 | #define slab (1UL << PG_slab) | |
6a46079c AK |
782 | #define reserved (1UL << PG_reserved) |
783 | ||
784 | static struct page_state { | |
785 | unsigned long mask; | |
786 | unsigned long res; | |
787 | char *msg; | |
788 | int (*action)(struct page *p, unsigned long pfn); | |
789 | } error_states[] = { | |
d95ea51e | 790 | { reserved, reserved, "reserved kernel", me_kernel }, |
95d01fc6 WF |
791 | /* |
792 | * free pages are specially detected outside this table: | |
793 | * PG_buddy pages only make a small fraction of all free pages. | |
794 | */ | |
6a46079c AK |
795 | |
796 | /* | |
797 | * Could in theory check if slab page is free or if we can drop | |
798 | * currently unused objects without touching them. But just | |
799 | * treat it as standard kernel for now. | |
800 | */ | |
801 | { slab, slab, "kernel slab", me_kernel }, | |
802 | ||
803 | #ifdef CONFIG_PAGEFLAGS_EXTENDED | |
804 | { head, head, "huge", me_huge_page }, | |
805 | { tail, tail, "huge", me_huge_page }, | |
806 | #else | |
807 | { compound, compound, "huge", me_huge_page }, | |
808 | #endif | |
809 | ||
ff604cf6 NH |
810 | { sc|dirty, sc|dirty, "dirty swapcache", me_swapcache_dirty }, |
811 | { sc|dirty, sc, "clean swapcache", me_swapcache_clean }, | |
6a46079c | 812 | |
ff604cf6 | 813 | { mlock|dirty, mlock|dirty, "dirty mlocked LRU", me_pagecache_dirty }, |
e3986295 | 814 | { mlock|dirty, mlock, "clean mlocked LRU", me_pagecache_clean }, |
6a46079c | 815 | |
5f4b9fc5 | 816 | { unevict|dirty, unevict|dirty, "dirty unevictable LRU", me_pagecache_dirty }, |
e3986295 | 817 | { unevict|dirty, unevict, "clean unevictable LRU", me_pagecache_clean }, |
5f4b9fc5 | 818 | |
ff604cf6 | 819 | { lru|dirty, lru|dirty, "dirty LRU", me_pagecache_dirty }, |
6a46079c | 820 | { lru|dirty, lru, "clean LRU", me_pagecache_clean }, |
6a46079c AK |
821 | |
822 | /* | |
823 | * Catchall entry: must be at end. | |
824 | */ | |
825 | { 0, 0, "unknown page state", me_unknown }, | |
826 | }; | |
827 | ||
2326c467 AK |
828 | #undef dirty |
829 | #undef sc | |
830 | #undef unevict | |
831 | #undef mlock | |
832 | #undef writeback | |
833 | #undef lru | |
834 | #undef swapbacked | |
835 | #undef head | |
836 | #undef tail | |
837 | #undef compound | |
838 | #undef slab | |
839 | #undef reserved | |
840 | ||
ff604cf6 NH |
841 | /* |
842 | * "Dirty/Clean" indication is not 100% accurate due to the possibility of | |
843 | * setting PG_dirty outside page lock. See also comment above set_page_dirty(). | |
844 | */ | |
6a46079c AK |
845 | static void action_result(unsigned long pfn, char *msg, int result) |
846 | { | |
ff604cf6 NH |
847 | pr_err("MCE %#lx: %s page recovery: %s\n", |
848 | pfn, msg, action_name[result]); | |
6a46079c AK |
849 | } |
850 | ||
851 | static int page_action(struct page_state *ps, struct page *p, | |
bd1ce5f9 | 852 | unsigned long pfn) |
6a46079c AK |
853 | { |
854 | int result; | |
7456b040 | 855 | int count; |
6a46079c AK |
856 | |
857 | result = ps->action(p, pfn); | |
7456b040 | 858 | |
bd1ce5f9 | 859 | count = page_count(p) - 1; |
138ce286 WF |
860 | if (ps->action == me_swapcache_dirty && result == DELAYED) |
861 | count--; | |
862 | if (count != 0) { | |
6a46079c AK |
863 | printk(KERN_ERR |
864 | "MCE %#lx: %s page still referenced by %d users\n", | |
7456b040 | 865 | pfn, ps->msg, count); |
138ce286 WF |
866 | result = FAILED; |
867 | } | |
6dc52cbe | 868 | action_result(pfn, ps->msg, result); |
6a46079c AK |
869 | |
870 | /* Could do more checks here if page looks ok */ | |
871 | /* | |
872 | * Could adjust zone counters here to correct for the missing page. | |
873 | */ | |
874 | ||
138ce286 | 875 | return (result == RECOVERED || result == DELAYED) ? 0 : -EBUSY; |
6a46079c AK |
876 | } |
877 | ||
6a46079c AK |
878 | /* |
879 | * Do all that is necessary to remove user space mappings. Unmap | |
880 | * the pages and send SIGBUS to the processes if the data was dirty. | |
881 | */ | |
1668bfd5 | 882 | static int hwpoison_user_mappings(struct page *p, unsigned long pfn, |
54b9dd14 | 883 | int trapno, int flags, struct page **hpagep) |
6a46079c AK |
884 | { |
885 | enum ttu_flags ttu = TTU_UNMAP | TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS; | |
886 | struct address_space *mapping; | |
887 | LIST_HEAD(tokill); | |
888 | int ret; | |
6751ed65 | 889 | int kill = 1, forcekill; |
54b9dd14 | 890 | struct page *hpage = *hpagep; |
a6d30ddd | 891 | struct page *ppage; |
6a46079c | 892 | |
93a9eb39 NH |
893 | /* |
894 | * Here we are interested only in user-mapped pages, so skip any | |
895 | * other types of pages. | |
896 | */ | |
897 | if (PageReserved(p) || PageSlab(p)) | |
898 | return SWAP_SUCCESS; | |
899 | if (!(PageLRU(hpage) || PageHuge(p))) | |
1668bfd5 | 900 | return SWAP_SUCCESS; |
6a46079c | 901 | |
6a46079c AK |
902 | /* |
903 | * This check implies we don't kill processes if their pages | |
904 | * are in the swap cache early. Those are always late kills. | |
905 | */ | |
7af446a8 | 906 | if (!page_mapped(hpage)) |
1668bfd5 WF |
907 | return SWAP_SUCCESS; |
908 | ||
52089b14 NH |
909 | if (PageKsm(p)) { |
910 | pr_err("MCE %#lx: can't handle KSM pages.\n", pfn); | |
1668bfd5 | 911 | return SWAP_FAIL; |
52089b14 | 912 | } |
6a46079c AK |
913 | |
914 | if (PageSwapCache(p)) { | |
915 | printk(KERN_ERR | |
916 | "MCE %#lx: keeping poisoned page in swap cache\n", pfn); | |
917 | ttu |= TTU_IGNORE_HWPOISON; | |
918 | } | |
919 | ||
920 | /* | |
921 | * Propagate the dirty bit from PTEs to struct page first, because we | |
922 | * need this to decide if we should kill or just drop the page. | |
db0480b3 WF |
923 | * XXX: the dirty test could be racy: set_page_dirty() may not always |
924 | * be called inside page lock (it's recommended but not enforced). | |
6a46079c | 925 | */ |
7af446a8 | 926 | mapping = page_mapping(hpage); |
6751ed65 | 927 | if (!(flags & MF_MUST_KILL) && !PageDirty(hpage) && mapping && |
7af446a8 NH |
928 | mapping_cap_writeback_dirty(mapping)) { |
929 | if (page_mkclean(hpage)) { | |
930 | SetPageDirty(hpage); | |
6a46079c AK |
931 | } else { |
932 | kill = 0; | |
933 | ttu |= TTU_IGNORE_HWPOISON; | |
934 | printk(KERN_INFO | |
935 | "MCE %#lx: corrupted page was clean: dropped without side effects\n", | |
936 | pfn); | |
937 | } | |
938 | } | |
939 | ||
a6d30ddd JD |
940 | /* |
941 | * ppage: poisoned page | |
942 | * if p is regular page(4k page) | |
943 | * ppage == real poisoned page; | |
944 | * else p is hugetlb or THP, ppage == head page. | |
945 | */ | |
946 | ppage = hpage; | |
947 | ||
efeda7a4 JD |
948 | if (PageTransHuge(hpage)) { |
949 | /* | |
950 | * Verify that this isn't a hugetlbfs head page, the check for | |
951 | * PageAnon is just for avoid tripping a split_huge_page | |
952 | * internal debug check, as split_huge_page refuses to deal with | |
953 | * anything that isn't an anon page. PageAnon can't go away fro | |
954 | * under us because we hold a refcount on the hpage, without a | |
955 | * refcount on the hpage. split_huge_page can't be safely called | |
956 | * in the first place, having a refcount on the tail isn't | |
957 | * enough * to be safe. | |
958 | */ | |
959 | if (!PageHuge(hpage) && PageAnon(hpage)) { | |
960 | if (unlikely(split_huge_page(hpage))) { | |
961 | /* | |
962 | * FIXME: if splitting THP is failed, it is | |
963 | * better to stop the following operation rather | |
964 | * than causing panic by unmapping. System might | |
965 | * survive if the page is freed later. | |
966 | */ | |
967 | printk(KERN_INFO | |
968 | "MCE %#lx: failed to split THP\n", pfn); | |
969 | ||
970 | BUG_ON(!PageHWPoison(p)); | |
971 | return SWAP_FAIL; | |
972 | } | |
a3e0f9e4 NH |
973 | /* |
974 | * We pinned the head page for hwpoison handling, | |
975 | * now we split the thp and we are interested in | |
976 | * the hwpoisoned raw page, so move the refcount | |
54b9dd14 | 977 | * to it. Similarly, page lock is shifted. |
a3e0f9e4 NH |
978 | */ |
979 | if (hpage != p) { | |
8d547ff4 NH |
980 | if (!(flags & MF_COUNT_INCREASED)) { |
981 | put_page(hpage); | |
982 | get_page(p); | |
983 | } | |
54b9dd14 NH |
984 | lock_page(p); |
985 | unlock_page(hpage); | |
986 | *hpagep = p; | |
a3e0f9e4 | 987 | } |
a6d30ddd JD |
988 | /* THP is split, so ppage should be the real poisoned page. */ |
989 | ppage = p; | |
efeda7a4 JD |
990 | } |
991 | } | |
992 | ||
6a46079c AK |
993 | /* |
994 | * First collect all the processes that have the page | |
995 | * mapped in dirty form. This has to be done before try_to_unmap, | |
996 | * because ttu takes the rmap data structures down. | |
997 | * | |
998 | * Error handling: We ignore errors here because | |
999 | * there's nothing that can be done. | |
1000 | */ | |
1001 | if (kill) | |
74614de1 | 1002 | collect_procs(ppage, &tokill, flags & MF_ACTION_REQUIRED); |
6a46079c | 1003 | |
a6d30ddd | 1004 | ret = try_to_unmap(ppage, ttu); |
6a46079c AK |
1005 | if (ret != SWAP_SUCCESS) |
1006 | printk(KERN_ERR "MCE %#lx: failed to unmap page (mapcount=%d)\n", | |
a6d30ddd JD |
1007 | pfn, page_mapcount(ppage)); |
1008 | ||
6a46079c AK |
1009 | /* |
1010 | * Now that the dirty bit has been propagated to the | |
1011 | * struct page and all unmaps done we can decide if | |
1012 | * killing is needed or not. Only kill when the page | |
6751ed65 TL |
1013 | * was dirty or the process is not restartable, |
1014 | * otherwise the tokill list is merely | |
6a46079c AK |
1015 | * freed. When there was a problem unmapping earlier |
1016 | * use a more force-full uncatchable kill to prevent | |
1017 | * any accesses to the poisoned memory. | |
1018 | */ | |
6751ed65 TL |
1019 | forcekill = PageDirty(ppage) || (flags & MF_MUST_KILL); |
1020 | kill_procs(&tokill, forcekill, trapno, | |
7329bbeb | 1021 | ret != SWAP_SUCCESS, p, pfn, flags); |
1668bfd5 WF |
1022 | |
1023 | return ret; | |
6a46079c AK |
1024 | } |
1025 | ||
7013febc NH |
1026 | static void set_page_hwpoison_huge_page(struct page *hpage) |
1027 | { | |
1028 | int i; | |
f9121153 | 1029 | int nr_pages = 1 << compound_order(hpage); |
7013febc NH |
1030 | for (i = 0; i < nr_pages; i++) |
1031 | SetPageHWPoison(hpage + i); | |
1032 | } | |
1033 | ||
1034 | static void clear_page_hwpoison_huge_page(struct page *hpage) | |
1035 | { | |
1036 | int i; | |
f9121153 | 1037 | int nr_pages = 1 << compound_order(hpage); |
7013febc NH |
1038 | for (i = 0; i < nr_pages; i++) |
1039 | ClearPageHWPoison(hpage + i); | |
1040 | } | |
1041 | ||
cd42f4a3 TL |
1042 | /** |
1043 | * memory_failure - Handle memory failure of a page. | |
1044 | * @pfn: Page Number of the corrupted page | |
1045 | * @trapno: Trap number reported in the signal to user space. | |
1046 | * @flags: fine tune action taken | |
1047 | * | |
1048 | * This function is called by the low level machine check code | |
1049 | * of an architecture when it detects hardware memory corruption | |
1050 | * of a page. It tries its best to recover, which includes | |
1051 | * dropping pages, killing processes etc. | |
1052 | * | |
1053 | * The function is primarily of use for corruptions that | |
1054 | * happen outside the current execution context (e.g. when | |
1055 | * detected by a background scrubber) | |
1056 | * | |
1057 | * Must run in process context (e.g. a work queue) with interrupts | |
1058 | * enabled and no spinlocks hold. | |
1059 | */ | |
1060 | int memory_failure(unsigned long pfn, int trapno, int flags) | |
6a46079c AK |
1061 | { |
1062 | struct page_state *ps; | |
1063 | struct page *p; | |
7af446a8 | 1064 | struct page *hpage; |
6a46079c | 1065 | int res; |
c9fbdd5f | 1066 | unsigned int nr_pages; |
524fca1e | 1067 | unsigned long page_flags; |
6a46079c AK |
1068 | |
1069 | if (!sysctl_memory_failure_recovery) | |
1070 | panic("Memory failure from trap %d on page %lx", trapno, pfn); | |
1071 | ||
1072 | if (!pfn_valid(pfn)) { | |
a7560fc8 WF |
1073 | printk(KERN_ERR |
1074 | "MCE %#lx: memory outside kernel control\n", | |
1075 | pfn); | |
1076 | return -ENXIO; | |
6a46079c AK |
1077 | } |
1078 | ||
1079 | p = pfn_to_page(pfn); | |
7af446a8 | 1080 | hpage = compound_head(p); |
6a46079c | 1081 | if (TestSetPageHWPoison(p)) { |
d95ea51e | 1082 | printk(KERN_ERR "MCE %#lx: already hardware poisoned\n", pfn); |
6a46079c AK |
1083 | return 0; |
1084 | } | |
1085 | ||
4db0e950 NH |
1086 | /* |
1087 | * Currently errors on hugetlbfs pages are measured in hugepage units, | |
1088 | * so nr_pages should be 1 << compound_order. OTOH when errors are on | |
1089 | * transparent hugepages, they are supposed to be split and error | |
1090 | * measurement is done in normal page units. So nr_pages should be one | |
1091 | * in this case. | |
1092 | */ | |
1093 | if (PageHuge(p)) | |
1094 | nr_pages = 1 << compound_order(hpage); | |
1095 | else /* normal page or thp */ | |
1096 | nr_pages = 1; | |
293c07e3 | 1097 | atomic_long_add(nr_pages, &num_poisoned_pages); |
6a46079c AK |
1098 | |
1099 | /* | |
1100 | * We need/can do nothing about count=0 pages. | |
1101 | * 1) it's a free page, and therefore in safe hand: | |
1102 | * prep_new_page() will be the gate keeper. | |
8c6c2ecb NH |
1103 | * 2) it's a free hugepage, which is also safe: |
1104 | * an affected hugepage will be dequeued from hugepage freelist, | |
1105 | * so there's no concern about reusing it ever after. | |
1106 | * 3) it's part of a non-compound high order page. | |
6a46079c AK |
1107 | * Implies some kernel user: cannot stop them from |
1108 | * R/W the page; let's pray that the page has been | |
1109 | * used and will be freed some time later. | |
1110 | * In fact it's dangerous to directly bump up page count from 0, | |
1111 | * that may make page_freeze_refs()/page_unfreeze_refs() mismatch. | |
1112 | */ | |
82ba011b | 1113 | if (!(flags & MF_COUNT_INCREASED) && |
7af446a8 | 1114 | !get_page_unless_zero(hpage)) { |
8d22ba1b WF |
1115 | if (is_free_buddy_page(p)) { |
1116 | action_result(pfn, "free buddy", DELAYED); | |
1117 | return 0; | |
8c6c2ecb NH |
1118 | } else if (PageHuge(hpage)) { |
1119 | /* | |
b985194c | 1120 | * Check "filter hit" and "race with other subpage." |
8c6c2ecb | 1121 | */ |
7eaceacc | 1122 | lock_page(hpage); |
b985194c CY |
1123 | if (PageHWPoison(hpage)) { |
1124 | if ((hwpoison_filter(p) && TestClearPageHWPoison(p)) | |
1125 | || (p != hpage && TestSetPageHWPoison(hpage))) { | |
1126 | atomic_long_sub(nr_pages, &num_poisoned_pages); | |
1127 | unlock_page(hpage); | |
1128 | return 0; | |
1129 | } | |
8c6c2ecb NH |
1130 | } |
1131 | set_page_hwpoison_huge_page(hpage); | |
1132 | res = dequeue_hwpoisoned_huge_page(hpage); | |
1133 | action_result(pfn, "free huge", | |
1134 | res ? IGNORED : DELAYED); | |
1135 | unlock_page(hpage); | |
1136 | return res; | |
8d22ba1b WF |
1137 | } else { |
1138 | action_result(pfn, "high order kernel", IGNORED); | |
1139 | return -EBUSY; | |
1140 | } | |
6a46079c AK |
1141 | } |
1142 | ||
e43c3afb WF |
1143 | /* |
1144 | * We ignore non-LRU pages for good reasons. | |
1145 | * - PG_locked is only well defined for LRU pages and a few others | |
1146 | * - to avoid races with __set_page_locked() | |
1147 | * - to avoid races with __SetPageSlab*() (and more non-atomic ops) | |
1148 | * The check (unnecessarily) ignores LRU pages being isolated and | |
1149 | * walked by the page reclaim code, however that's not a big loss. | |
1150 | */ | |
385de357 | 1151 | if (!PageHuge(p) && !PageTransTail(p)) { |
af241a08 JD |
1152 | if (!PageLRU(p)) |
1153 | shake_page(p, 0); | |
1154 | if (!PageLRU(p)) { | |
1155 | /* | |
1156 | * shake_page could have turned it free. | |
1157 | */ | |
1158 | if (is_free_buddy_page(p)) { | |
2d421acd WL |
1159 | if (flags & MF_COUNT_INCREASED) |
1160 | action_result(pfn, "free buddy", DELAYED); | |
1161 | else | |
1162 | action_result(pfn, "free buddy, 2nd try", DELAYED); | |
af241a08 JD |
1163 | return 0; |
1164 | } | |
0474a60e | 1165 | } |
e43c3afb | 1166 | } |
e43c3afb | 1167 | |
7eaceacc | 1168 | lock_page(hpage); |
847ce401 | 1169 | |
f37d4298 AK |
1170 | /* |
1171 | * The page could have changed compound pages during the locking. | |
1172 | * If this happens just bail out. | |
1173 | */ | |
1174 | if (compound_head(p) != hpage) { | |
1175 | action_result(pfn, "different compound page after locking", IGNORED); | |
1176 | res = -EBUSY; | |
1177 | goto out; | |
1178 | } | |
1179 | ||
524fca1e NH |
1180 | /* |
1181 | * We use page flags to determine what action should be taken, but | |
1182 | * the flags can be modified by the error containment action. One | |
1183 | * example is an mlocked page, where PG_mlocked is cleared by | |
1184 | * page_remove_rmap() in try_to_unmap_one(). So to determine page status | |
1185 | * correctly, we save a copy of the page flags at this time. | |
1186 | */ | |
1187 | page_flags = p->flags; | |
1188 | ||
847ce401 WF |
1189 | /* |
1190 | * unpoison always clear PG_hwpoison inside page lock | |
1191 | */ | |
1192 | if (!PageHWPoison(p)) { | |
d95ea51e | 1193 | printk(KERN_ERR "MCE %#lx: just unpoisoned\n", pfn); |
3e030ecc NH |
1194 | atomic_long_sub(nr_pages, &num_poisoned_pages); |
1195 | put_page(hpage); | |
847ce401 WF |
1196 | res = 0; |
1197 | goto out; | |
1198 | } | |
7c116f2b WF |
1199 | if (hwpoison_filter(p)) { |
1200 | if (TestClearPageHWPoison(p)) | |
293c07e3 | 1201 | atomic_long_sub(nr_pages, &num_poisoned_pages); |
7af446a8 NH |
1202 | unlock_page(hpage); |
1203 | put_page(hpage); | |
7c116f2b WF |
1204 | return 0; |
1205 | } | |
847ce401 | 1206 | |
0bc1f8b0 CY |
1207 | if (!PageHuge(p) && !PageTransTail(p) && !PageLRU(p)) |
1208 | goto identify_page_state; | |
1209 | ||
7013febc NH |
1210 | /* |
1211 | * For error on the tail page, we should set PG_hwpoison | |
1212 | * on the head page to show that the hugepage is hwpoisoned | |
1213 | */ | |
a6d30ddd | 1214 | if (PageHuge(p) && PageTail(p) && TestSetPageHWPoison(hpage)) { |
7013febc NH |
1215 | action_result(pfn, "hugepage already hardware poisoned", |
1216 | IGNORED); | |
1217 | unlock_page(hpage); | |
1218 | put_page(hpage); | |
1219 | return 0; | |
1220 | } | |
1221 | /* | |
1222 | * Set PG_hwpoison on all pages in an error hugepage, | |
1223 | * because containment is done in hugepage unit for now. | |
1224 | * Since we have done TestSetPageHWPoison() for the head page with | |
1225 | * page lock held, we can safely set PG_hwpoison bits on tail pages. | |
1226 | */ | |
1227 | if (PageHuge(p)) | |
1228 | set_page_hwpoison_huge_page(hpage); | |
1229 | ||
6edd6cc6 NH |
1230 | /* |
1231 | * It's very difficult to mess with pages currently under IO | |
1232 | * and in many cases impossible, so we just avoid it here. | |
1233 | */ | |
6a46079c AK |
1234 | wait_on_page_writeback(p); |
1235 | ||
1236 | /* | |
1237 | * Now take care of user space mappings. | |
e64a782f | 1238 | * Abort on fail: __delete_from_page_cache() assumes unmapped page. |
54b9dd14 NH |
1239 | * |
1240 | * When the raw error page is thp tail page, hpage points to the raw | |
1241 | * page after thp split. | |
6a46079c | 1242 | */ |
54b9dd14 NH |
1243 | if (hwpoison_user_mappings(p, pfn, trapno, flags, &hpage) |
1244 | != SWAP_SUCCESS) { | |
52089b14 | 1245 | action_result(pfn, "unmapping failed", IGNORED); |
1668bfd5 WF |
1246 | res = -EBUSY; |
1247 | goto out; | |
1248 | } | |
6a46079c AK |
1249 | |
1250 | /* | |
1251 | * Torn down by someone else? | |
1252 | */ | |
dc2a1cbf | 1253 | if (PageLRU(p) && !PageSwapCache(p) && p->mapping == NULL) { |
6a46079c | 1254 | action_result(pfn, "already truncated LRU", IGNORED); |
d95ea51e | 1255 | res = -EBUSY; |
6a46079c AK |
1256 | goto out; |
1257 | } | |
1258 | ||
0bc1f8b0 | 1259 | identify_page_state: |
6a46079c | 1260 | res = -EBUSY; |
524fca1e NH |
1261 | /* |
1262 | * The first check uses the current page flags which may not have any | |
1263 | * relevant information. The second check with the saved page flagss is | |
1264 | * carried out only if the first check can't determine the page status. | |
1265 | */ | |
1266 | for (ps = error_states;; ps++) | |
1267 | if ((p->flags & ps->mask) == ps->res) | |
6a46079c | 1268 | break; |
841fcc58 WL |
1269 | |
1270 | page_flags |= (p->flags & (1UL << PG_dirty)); | |
1271 | ||
524fca1e NH |
1272 | if (!ps->mask) |
1273 | for (ps = error_states;; ps++) | |
1274 | if ((page_flags & ps->mask) == ps->res) | |
1275 | break; | |
1276 | res = page_action(ps, p, pfn); | |
6a46079c | 1277 | out: |
7af446a8 | 1278 | unlock_page(hpage); |
6a46079c AK |
1279 | return res; |
1280 | } | |
cd42f4a3 | 1281 | EXPORT_SYMBOL_GPL(memory_failure); |
847ce401 | 1282 | |
ea8f5fb8 HY |
1283 | #define MEMORY_FAILURE_FIFO_ORDER 4 |
1284 | #define MEMORY_FAILURE_FIFO_SIZE (1 << MEMORY_FAILURE_FIFO_ORDER) | |
1285 | ||
1286 | struct memory_failure_entry { | |
1287 | unsigned long pfn; | |
1288 | int trapno; | |
1289 | int flags; | |
1290 | }; | |
1291 | ||
1292 | struct memory_failure_cpu { | |
1293 | DECLARE_KFIFO(fifo, struct memory_failure_entry, | |
1294 | MEMORY_FAILURE_FIFO_SIZE); | |
1295 | spinlock_t lock; | |
1296 | struct work_struct work; | |
1297 | }; | |
1298 | ||
1299 | static DEFINE_PER_CPU(struct memory_failure_cpu, memory_failure_cpu); | |
1300 | ||
1301 | /** | |
1302 | * memory_failure_queue - Schedule handling memory failure of a page. | |
1303 | * @pfn: Page Number of the corrupted page | |
1304 | * @trapno: Trap number reported in the signal to user space. | |
1305 | * @flags: Flags for memory failure handling | |
1306 | * | |
1307 | * This function is called by the low level hardware error handler | |
1308 | * when it detects hardware memory corruption of a page. It schedules | |
1309 | * the recovering of error page, including dropping pages, killing | |
1310 | * processes etc. | |
1311 | * | |
1312 | * The function is primarily of use for corruptions that | |
1313 | * happen outside the current execution context (e.g. when | |
1314 | * detected by a background scrubber) | |
1315 | * | |
1316 | * Can run in IRQ context. | |
1317 | */ | |
1318 | void memory_failure_queue(unsigned long pfn, int trapno, int flags) | |
1319 | { | |
1320 | struct memory_failure_cpu *mf_cpu; | |
1321 | unsigned long proc_flags; | |
1322 | struct memory_failure_entry entry = { | |
1323 | .pfn = pfn, | |
1324 | .trapno = trapno, | |
1325 | .flags = flags, | |
1326 | }; | |
1327 | ||
1328 | mf_cpu = &get_cpu_var(memory_failure_cpu); | |
1329 | spin_lock_irqsave(&mf_cpu->lock, proc_flags); | |
498d319b | 1330 | if (kfifo_put(&mf_cpu->fifo, entry)) |
ea8f5fb8 HY |
1331 | schedule_work_on(smp_processor_id(), &mf_cpu->work); |
1332 | else | |
8e33a52f | 1333 | pr_err("Memory failure: buffer overflow when queuing memory failure at %#lx\n", |
ea8f5fb8 HY |
1334 | pfn); |
1335 | spin_unlock_irqrestore(&mf_cpu->lock, proc_flags); | |
1336 | put_cpu_var(memory_failure_cpu); | |
1337 | } | |
1338 | EXPORT_SYMBOL_GPL(memory_failure_queue); | |
1339 | ||
1340 | static void memory_failure_work_func(struct work_struct *work) | |
1341 | { | |
1342 | struct memory_failure_cpu *mf_cpu; | |
1343 | struct memory_failure_entry entry = { 0, }; | |
1344 | unsigned long proc_flags; | |
1345 | int gotten; | |
1346 | ||
7c8e0181 | 1347 | mf_cpu = this_cpu_ptr(&memory_failure_cpu); |
ea8f5fb8 HY |
1348 | for (;;) { |
1349 | spin_lock_irqsave(&mf_cpu->lock, proc_flags); | |
1350 | gotten = kfifo_get(&mf_cpu->fifo, &entry); | |
1351 | spin_unlock_irqrestore(&mf_cpu->lock, proc_flags); | |
1352 | if (!gotten) | |
1353 | break; | |
cf870c70 NR |
1354 | if (entry.flags & MF_SOFT_OFFLINE) |
1355 | soft_offline_page(pfn_to_page(entry.pfn), entry.flags); | |
1356 | else | |
1357 | memory_failure(entry.pfn, entry.trapno, entry.flags); | |
ea8f5fb8 HY |
1358 | } |
1359 | } | |
1360 | ||
1361 | static int __init memory_failure_init(void) | |
1362 | { | |
1363 | struct memory_failure_cpu *mf_cpu; | |
1364 | int cpu; | |
1365 | ||
1366 | for_each_possible_cpu(cpu) { | |
1367 | mf_cpu = &per_cpu(memory_failure_cpu, cpu); | |
1368 | spin_lock_init(&mf_cpu->lock); | |
1369 | INIT_KFIFO(mf_cpu->fifo); | |
1370 | INIT_WORK(&mf_cpu->work, memory_failure_work_func); | |
1371 | } | |
1372 | ||
1373 | return 0; | |
1374 | } | |
1375 | core_initcall(memory_failure_init); | |
1376 | ||
847ce401 WF |
1377 | /** |
1378 | * unpoison_memory - Unpoison a previously poisoned page | |
1379 | * @pfn: Page number of the to be unpoisoned page | |
1380 | * | |
1381 | * Software-unpoison a page that has been poisoned by | |
1382 | * memory_failure() earlier. | |
1383 | * | |
1384 | * This is only done on the software-level, so it only works | |
1385 | * for linux injected failures, not real hardware failures | |
1386 | * | |
1387 | * Returns 0 for success, otherwise -errno. | |
1388 | */ | |
1389 | int unpoison_memory(unsigned long pfn) | |
1390 | { | |
1391 | struct page *page; | |
1392 | struct page *p; | |
1393 | int freeit = 0; | |
c9fbdd5f | 1394 | unsigned int nr_pages; |
847ce401 WF |
1395 | |
1396 | if (!pfn_valid(pfn)) | |
1397 | return -ENXIO; | |
1398 | ||
1399 | p = pfn_to_page(pfn); | |
1400 | page = compound_head(p); | |
1401 | ||
1402 | if (!PageHWPoison(p)) { | |
fb46e735 | 1403 | pr_info("MCE: Page was already unpoisoned %#lx\n", pfn); |
847ce401 WF |
1404 | return 0; |
1405 | } | |
1406 | ||
0cea3fdc WL |
1407 | /* |
1408 | * unpoison_memory() can encounter thp only when the thp is being | |
1409 | * worked by memory_failure() and the page lock is not held yet. | |
1410 | * In such case, we yield to memory_failure() and make unpoison fail. | |
1411 | */ | |
e76d30e2 | 1412 | if (!PageHuge(page) && PageTransHuge(page)) { |
0cea3fdc WL |
1413 | pr_info("MCE: Memory failure is now running on %#lx\n", pfn); |
1414 | return 0; | |
1415 | } | |
1416 | ||
f9121153 | 1417 | nr_pages = 1 << compound_order(page); |
c9fbdd5f | 1418 | |
847ce401 | 1419 | if (!get_page_unless_zero(page)) { |
8c6c2ecb NH |
1420 | /* |
1421 | * Since HWPoisoned hugepage should have non-zero refcount, | |
1422 | * race between memory failure and unpoison seems to happen. | |
1423 | * In such case unpoison fails and memory failure runs | |
1424 | * to the end. | |
1425 | */ | |
1426 | if (PageHuge(page)) { | |
dd73e85f | 1427 | pr_info("MCE: Memory failure is now running on free hugepage %#lx\n", pfn); |
8c6c2ecb NH |
1428 | return 0; |
1429 | } | |
847ce401 | 1430 | if (TestClearPageHWPoison(p)) |
dd9538a5 | 1431 | atomic_long_dec(&num_poisoned_pages); |
fb46e735 | 1432 | pr_info("MCE: Software-unpoisoned free page %#lx\n", pfn); |
847ce401 WF |
1433 | return 0; |
1434 | } | |
1435 | ||
7eaceacc | 1436 | lock_page(page); |
847ce401 WF |
1437 | /* |
1438 | * This test is racy because PG_hwpoison is set outside of page lock. | |
1439 | * That's acceptable because that won't trigger kernel panic. Instead, | |
1440 | * the PG_hwpoison page will be caught and isolated on the entrance to | |
1441 | * the free buddy page pool. | |
1442 | */ | |
c9fbdd5f | 1443 | if (TestClearPageHWPoison(page)) { |
fb46e735 | 1444 | pr_info("MCE: Software-unpoisoned page %#lx\n", pfn); |
293c07e3 | 1445 | atomic_long_sub(nr_pages, &num_poisoned_pages); |
847ce401 | 1446 | freeit = 1; |
6a90181c NH |
1447 | if (PageHuge(page)) |
1448 | clear_page_hwpoison_huge_page(page); | |
847ce401 WF |
1449 | } |
1450 | unlock_page(page); | |
1451 | ||
1452 | put_page(page); | |
3ba5eebc | 1453 | if (freeit && !(pfn == my_zero_pfn(0) && page_count(p) == 1)) |
847ce401 WF |
1454 | put_page(page); |
1455 | ||
1456 | return 0; | |
1457 | } | |
1458 | EXPORT_SYMBOL(unpoison_memory); | |
facb6011 AK |
1459 | |
1460 | static struct page *new_page(struct page *p, unsigned long private, int **x) | |
1461 | { | |
12686d15 | 1462 | int nid = page_to_nid(p); |
d950b958 NH |
1463 | if (PageHuge(p)) |
1464 | return alloc_huge_page_node(page_hstate(compound_head(p)), | |
1465 | nid); | |
1466 | else | |
1467 | return alloc_pages_exact_node(nid, GFP_HIGHUSER_MOVABLE, 0); | |
facb6011 AK |
1468 | } |
1469 | ||
1470 | /* | |
1471 | * Safely get reference count of an arbitrary page. | |
1472 | * Returns 0 for a free page, -EIO for a zero refcount page | |
1473 | * that is not free, and 1 for any other page type. | |
1474 | * For 1 the page is returned with increased page count, otherwise not. | |
1475 | */ | |
af8fae7c | 1476 | static int __get_any_page(struct page *p, unsigned long pfn, int flags) |
facb6011 AK |
1477 | { |
1478 | int ret; | |
1479 | ||
1480 | if (flags & MF_COUNT_INCREASED) | |
1481 | return 1; | |
1482 | ||
d950b958 NH |
1483 | /* |
1484 | * When the target page is a free hugepage, just remove it | |
1485 | * from free hugepage list. | |
1486 | */ | |
facb6011 | 1487 | if (!get_page_unless_zero(compound_head(p))) { |
d950b958 | 1488 | if (PageHuge(p)) { |
71dd0b8a | 1489 | pr_info("%s: %#lx free huge page\n", __func__, pfn); |
af8fae7c | 1490 | ret = 0; |
d950b958 | 1491 | } else if (is_free_buddy_page(p)) { |
71dd0b8a | 1492 | pr_info("%s: %#lx free buddy page\n", __func__, pfn); |
facb6011 AK |
1493 | ret = 0; |
1494 | } else { | |
71dd0b8a BP |
1495 | pr_info("%s: %#lx: unknown zero refcount page type %lx\n", |
1496 | __func__, pfn, p->flags); | |
facb6011 AK |
1497 | ret = -EIO; |
1498 | } | |
1499 | } else { | |
1500 | /* Not a free page */ | |
1501 | ret = 1; | |
1502 | } | |
facb6011 AK |
1503 | return ret; |
1504 | } | |
1505 | ||
af8fae7c NH |
1506 | static int get_any_page(struct page *page, unsigned long pfn, int flags) |
1507 | { | |
1508 | int ret = __get_any_page(page, pfn, flags); | |
1509 | ||
1510 | if (ret == 1 && !PageHuge(page) && !PageLRU(page)) { | |
1511 | /* | |
1512 | * Try to free it. | |
1513 | */ | |
1514 | put_page(page); | |
1515 | shake_page(page, 1); | |
1516 | ||
1517 | /* | |
1518 | * Did it turn free? | |
1519 | */ | |
1520 | ret = __get_any_page(page, pfn, 0); | |
1521 | if (!PageLRU(page)) { | |
1522 | pr_info("soft_offline: %#lx: unknown non LRU page type %lx\n", | |
1523 | pfn, page->flags); | |
1524 | return -EIO; | |
1525 | } | |
1526 | } | |
1527 | return ret; | |
1528 | } | |
1529 | ||
d950b958 NH |
1530 | static int soft_offline_huge_page(struct page *page, int flags) |
1531 | { | |
1532 | int ret; | |
1533 | unsigned long pfn = page_to_pfn(page); | |
1534 | struct page *hpage = compound_head(page); | |
b8ec1cee | 1535 | LIST_HEAD(pagelist); |
d950b958 | 1536 | |
af8fae7c NH |
1537 | /* |
1538 | * This double-check of PageHWPoison is to avoid the race with | |
1539 | * memory_failure(). See also comment in __soft_offline_page(). | |
1540 | */ | |
1541 | lock_page(hpage); | |
0ebff32c | 1542 | if (PageHWPoison(hpage)) { |
af8fae7c NH |
1543 | unlock_page(hpage); |
1544 | put_page(hpage); | |
0ebff32c | 1545 | pr_info("soft offline: %#lx hugepage already poisoned\n", pfn); |
af8fae7c | 1546 | return -EBUSY; |
0ebff32c | 1547 | } |
af8fae7c | 1548 | unlock_page(hpage); |
d950b958 | 1549 | |
d950b958 | 1550 | /* Keep page count to indicate a given hugepage is isolated. */ |
b8ec1cee | 1551 | list_move(&hpage->lru, &pagelist); |
68711a74 | 1552 | ret = migrate_pages(&pagelist, new_page, NULL, MPOL_MF_MOVE_ALL, |
b8ec1cee | 1553 | MIGRATE_SYNC, MR_MEMORY_FAILURE); |
d950b958 | 1554 | if (ret) { |
dd73e85f DN |
1555 | pr_info("soft offline: %#lx: migration failed %d, type %lx\n", |
1556 | pfn, ret, page->flags); | |
b8ec1cee NH |
1557 | /* |
1558 | * We know that soft_offline_huge_page() tries to migrate | |
1559 | * only one hugepage pointed to by hpage, so we need not | |
1560 | * run through the pagelist here. | |
1561 | */ | |
1562 | putback_active_hugepage(hpage); | |
1563 | if (ret > 0) | |
1564 | ret = -EIO; | |
af8fae7c | 1565 | } else { |
a49ecbcd JW |
1566 | /* overcommit hugetlb page will be freed to buddy */ |
1567 | if (PageHuge(page)) { | |
1568 | set_page_hwpoison_huge_page(hpage); | |
1569 | dequeue_hwpoisoned_huge_page(hpage); | |
1570 | atomic_long_add(1 << compound_order(hpage), | |
1571 | &num_poisoned_pages); | |
1572 | } else { | |
1573 | SetPageHWPoison(page); | |
1574 | atomic_long_inc(&num_poisoned_pages); | |
1575 | } | |
d950b958 | 1576 | } |
d950b958 NH |
1577 | return ret; |
1578 | } | |
1579 | ||
af8fae7c NH |
1580 | static int __soft_offline_page(struct page *page, int flags) |
1581 | { | |
1582 | int ret; | |
1583 | unsigned long pfn = page_to_pfn(page); | |
facb6011 | 1584 | |
facb6011 | 1585 | /* |
af8fae7c NH |
1586 | * Check PageHWPoison again inside page lock because PageHWPoison |
1587 | * is set by memory_failure() outside page lock. Note that | |
1588 | * memory_failure() also double-checks PageHWPoison inside page lock, | |
1589 | * so there's no race between soft_offline_page() and memory_failure(). | |
facb6011 | 1590 | */ |
0ebff32c XQ |
1591 | lock_page(page); |
1592 | wait_on_page_writeback(page); | |
af8fae7c NH |
1593 | if (PageHWPoison(page)) { |
1594 | unlock_page(page); | |
1595 | put_page(page); | |
1596 | pr_info("soft offline: %#lx page already poisoned\n", pfn); | |
1597 | return -EBUSY; | |
1598 | } | |
facb6011 AK |
1599 | /* |
1600 | * Try to invalidate first. This should work for | |
1601 | * non dirty unmapped page cache pages. | |
1602 | */ | |
1603 | ret = invalidate_inode_page(page); | |
1604 | unlock_page(page); | |
facb6011 | 1605 | /* |
facb6011 AK |
1606 | * RED-PEN would be better to keep it isolated here, but we |
1607 | * would need to fix isolation locking first. | |
1608 | */ | |
facb6011 | 1609 | if (ret == 1) { |
bd486285 | 1610 | put_page(page); |
fb46e735 | 1611 | pr_info("soft_offline: %#lx: invalidated\n", pfn); |
af8fae7c NH |
1612 | SetPageHWPoison(page); |
1613 | atomic_long_inc(&num_poisoned_pages); | |
1614 | return 0; | |
facb6011 AK |
1615 | } |
1616 | ||
1617 | /* | |
1618 | * Simple invalidation didn't work. | |
1619 | * Try to migrate to a new page instead. migrate.c | |
1620 | * handles a large number of cases for us. | |
1621 | */ | |
1622 | ret = isolate_lru_page(page); | |
bd486285 KK |
1623 | /* |
1624 | * Drop page reference which is came from get_any_page() | |
1625 | * successful isolate_lru_page() already took another one. | |
1626 | */ | |
1627 | put_page(page); | |
facb6011 AK |
1628 | if (!ret) { |
1629 | LIST_HEAD(pagelist); | |
5db8a73a | 1630 | inc_zone_page_state(page, NR_ISOLATED_ANON + |
9c620e2b | 1631 | page_is_file_cache(page)); |
facb6011 | 1632 | list_add(&page->lru, &pagelist); |
68711a74 | 1633 | ret = migrate_pages(&pagelist, new_page, NULL, MPOL_MF_MOVE_ALL, |
9c620e2b | 1634 | MIGRATE_SYNC, MR_MEMORY_FAILURE); |
facb6011 | 1635 | if (ret) { |
59c82b70 JK |
1636 | if (!list_empty(&pagelist)) { |
1637 | list_del(&page->lru); | |
1638 | dec_zone_page_state(page, NR_ISOLATED_ANON + | |
1639 | page_is_file_cache(page)); | |
1640 | putback_lru_page(page); | |
1641 | } | |
1642 | ||
fb46e735 | 1643 | pr_info("soft offline: %#lx: migration failed %d, type %lx\n", |
facb6011 AK |
1644 | pfn, ret, page->flags); |
1645 | if (ret > 0) | |
1646 | ret = -EIO; | |
af8fae7c | 1647 | } else { |
f15bdfa8 NH |
1648 | /* |
1649 | * After page migration succeeds, the source page can | |
1650 | * be trapped in pagevec and actual freeing is delayed. | |
1651 | * Freeing code works differently based on PG_hwpoison, | |
1652 | * so there's a race. We need to make sure that the | |
1653 | * source page should be freed back to buddy before | |
1654 | * setting PG_hwpoison. | |
1655 | */ | |
1656 | if (!is_free_buddy_page(page)) | |
1657 | lru_add_drain_all(); | |
1658 | if (!is_free_buddy_page(page)) | |
c0554329 | 1659 | drain_all_pages(page_zone(page)); |
af8fae7c | 1660 | SetPageHWPoison(page); |
f15bdfa8 NH |
1661 | if (!is_free_buddy_page(page)) |
1662 | pr_info("soft offline: %#lx: page leaked\n", | |
1663 | pfn); | |
af8fae7c | 1664 | atomic_long_inc(&num_poisoned_pages); |
facb6011 AK |
1665 | } |
1666 | } else { | |
fb46e735 | 1667 | pr_info("soft offline: %#lx: isolation failed: %d, page count %d, type %lx\n", |
dd73e85f | 1668 | pfn, ret, page_count(page), page->flags); |
facb6011 | 1669 | } |
facb6011 AK |
1670 | return ret; |
1671 | } | |
86e05773 WL |
1672 | |
1673 | /** | |
1674 | * soft_offline_page - Soft offline a page. | |
1675 | * @page: page to offline | |
1676 | * @flags: flags. Same as memory_failure(). | |
1677 | * | |
1678 | * Returns 0 on success, otherwise negated errno. | |
1679 | * | |
1680 | * Soft offline a page, by migration or invalidation, | |
1681 | * without killing anything. This is for the case when | |
1682 | * a page is not corrupted yet (so it's still valid to access), | |
1683 | * but has had a number of corrected errors and is better taken | |
1684 | * out. | |
1685 | * | |
1686 | * The actual policy on when to do that is maintained by | |
1687 | * user space. | |
1688 | * | |
1689 | * This should never impact any application or cause data loss, | |
1690 | * however it might take some time. | |
1691 | * | |
1692 | * This is not a 100% solution for all memory, but tries to be | |
1693 | * ``good enough'' for the majority of memory. | |
1694 | */ | |
1695 | int soft_offline_page(struct page *page, int flags) | |
1696 | { | |
1697 | int ret; | |
1698 | unsigned long pfn = page_to_pfn(page); | |
668f9abb | 1699 | struct page *hpage = compound_head(page); |
86e05773 WL |
1700 | |
1701 | if (PageHWPoison(page)) { | |
1702 | pr_info("soft offline: %#lx page already poisoned\n", pfn); | |
1703 | return -EBUSY; | |
1704 | } | |
1705 | if (!PageHuge(page) && PageTransHuge(hpage)) { | |
1706 | if (PageAnon(hpage) && unlikely(split_huge_page(hpage))) { | |
1707 | pr_info("soft offline: %#lx: failed to split THP\n", | |
1708 | pfn); | |
1709 | return -EBUSY; | |
1710 | } | |
1711 | } | |
1712 | ||
bfc8c901 | 1713 | get_online_mems(); |
03b61ff3 NH |
1714 | |
1715 | /* | |
1716 | * Isolate the page, so that it doesn't get reallocated if it | |
1717 | * was free. This flag should be kept set until the source page | |
1718 | * is freed and PG_hwpoison on it is set. | |
1719 | */ | |
1720 | if (get_pageblock_migratetype(page) != MIGRATE_ISOLATE) | |
1721 | set_migratetype_isolate(page, true); | |
1722 | ||
86e05773 | 1723 | ret = get_any_page(page, pfn, flags); |
bfc8c901 | 1724 | put_online_mems(); |
03b61ff3 | 1725 | if (ret > 0) { /* for in-use pages */ |
86e05773 WL |
1726 | if (PageHuge(page)) |
1727 | ret = soft_offline_huge_page(page, flags); | |
1728 | else | |
1729 | ret = __soft_offline_page(page, flags); | |
03b61ff3 | 1730 | } else if (ret == 0) { /* for free pages */ |
86e05773 WL |
1731 | if (PageHuge(page)) { |
1732 | set_page_hwpoison_huge_page(hpage); | |
1733 | dequeue_hwpoisoned_huge_page(hpage); | |
1734 | atomic_long_add(1 << compound_order(hpage), | |
1735 | &num_poisoned_pages); | |
1736 | } else { | |
1737 | SetPageHWPoison(page); | |
1738 | atomic_long_inc(&num_poisoned_pages); | |
1739 | } | |
1740 | } | |
86e05773 WL |
1741 | unset_migratetype_isolate(page, MIGRATE_MOVABLE); |
1742 | return ret; | |
1743 | } |