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Andi Kleen6a460792009-09-16 11:50:15 +02001/*
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
Andi Kleen1c80b992010-09-27 23:09:51 +020010 * hardware as being corrupted usually due to a multi-bit ECC memory or cache
Andi Kleen6a460792009-09-16 11:50:15 +020011 * failure.
Andi Kleen1c80b992010-09-27 23:09:51 +020012 *
13 * In addition there is a "soft offline" entry point that allows stop using
14 * not-yet-corrupted-by-suspicious pages without killing anything.
Andi Kleen6a460792009-09-16 11:50:15 +020015 *
16 * Handles page cache pages in various states. The tricky part
Andi Kleen1c80b992010-09-27 23:09:51 +020017 * 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.
Andi Kleene0de78d2015-06-24 16:56:02 -070023 *
24 * It can be very tempting to add handling for obscure cases here.
25 * In general any code for handling new cases should only be added iff:
26 * - You know how to test it.
27 * - You have a test that can be added to mce-test
28 * https://git.kernel.org/cgit/utils/cpu/mce/mce-test.git/
29 * - The case actually shows up as a frequent (top 10) page state in
30 * tools/vm/page-types when running a real workload.
Andi Kleen1c80b992010-09-27 23:09:51 +020031 *
32 * There are several operations here with exponential complexity because
33 * of unsuitable VM data structures. For example the operation to map back
34 * from RMAP chains to processes has to walk the complete process list and
35 * has non linear complexity with the number. But since memory corruptions
36 * are rare we hope to get away with this. This avoids impacting the core
37 * VM.
Andi Kleen6a460792009-09-16 11:50:15 +020038 */
Andi Kleen6a460792009-09-16 11:50:15 +020039#include <linux/kernel.h>
40#include <linux/mm.h>
41#include <linux/page-flags.h>
Wu Fengguang478c5ff2009-12-16 12:19:59 +010042#include <linux/kernel-page-flags.h>
Andi Kleen6a460792009-09-16 11:50:15 +020043#include <linux/sched.h>
Hugh Dickins01e00f82009-10-13 15:02:11 +010044#include <linux/ksm.h>
Andi Kleen6a460792009-09-16 11:50:15 +020045#include <linux/rmap.h>
Paul Gortmakerb9e15ba2011-05-26 16:00:52 -040046#include <linux/export.h>
Andi Kleen6a460792009-09-16 11:50:15 +020047#include <linux/pagemap.h>
48#include <linux/swap.h>
49#include <linux/backing-dev.h>
Andi Kleenfacb6012009-12-16 12:20:00 +010050#include <linux/migrate.h>
51#include <linux/page-isolation.h>
52#include <linux/suspend.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090053#include <linux/slab.h>
Huang Yingbf998152010-05-31 14:28:19 +080054#include <linux/swapops.h>
Naoya Horiguchi7af446a2010-05-28 09:29:17 +090055#include <linux/hugetlb.h>
KOSAKI Motohiro20d6c962010-12-02 14:31:19 -080056#include <linux/memory_hotplug.h>
Minchan Kim5db8a732011-06-15 15:08:48 -070057#include <linux/mm_inline.h>
Huang Yingea8f5fb2011-07-13 13:14:27 +080058#include <linux/kfifo.h>
Andi Kleen6a460792009-09-16 11:50:15 +020059#include "internal.h"
Xie XiuQi97f0b132015-06-24 16:57:36 -070060#include "ras/ras_event.h"
Andi Kleen6a460792009-09-16 11:50:15 +020061
62int sysctl_memory_failure_early_kill __read_mostly = 0;
63
64int sysctl_memory_failure_recovery __read_mostly = 1;
65
Xishi Qiu293c07e2013-02-22 16:34:02 -080066atomic_long_t num_poisoned_pages __read_mostly = ATOMIC_LONG_INIT(0);
Andi Kleen6a460792009-09-16 11:50:15 +020067
Andi Kleen27df5062009-12-21 19:56:42 +010068#if defined(CONFIG_HWPOISON_INJECT) || defined(CONFIG_HWPOISON_INJECT_MODULE)
69
Haicheng Li1bfe5fe2009-12-16 12:19:59 +010070u32 hwpoison_filter_enable = 0;
Wu Fengguang7c116f22009-12-16 12:19:59 +010071u32 hwpoison_filter_dev_major = ~0U;
72u32 hwpoison_filter_dev_minor = ~0U;
Wu Fengguang478c5ff2009-12-16 12:19:59 +010073u64 hwpoison_filter_flags_mask;
74u64 hwpoison_filter_flags_value;
Haicheng Li1bfe5fe2009-12-16 12:19:59 +010075EXPORT_SYMBOL_GPL(hwpoison_filter_enable);
Wu Fengguang7c116f22009-12-16 12:19:59 +010076EXPORT_SYMBOL_GPL(hwpoison_filter_dev_major);
77EXPORT_SYMBOL_GPL(hwpoison_filter_dev_minor);
Wu Fengguang478c5ff2009-12-16 12:19:59 +010078EXPORT_SYMBOL_GPL(hwpoison_filter_flags_mask);
79EXPORT_SYMBOL_GPL(hwpoison_filter_flags_value);
Wu Fengguang7c116f22009-12-16 12:19:59 +010080
81static int hwpoison_filter_dev(struct page *p)
82{
83 struct address_space *mapping;
84 dev_t dev;
85
86 if (hwpoison_filter_dev_major == ~0U &&
87 hwpoison_filter_dev_minor == ~0U)
88 return 0;
89
90 /*
Andi Kleen1c80b992010-09-27 23:09:51 +020091 * page_mapping() does not accept slab pages.
Wu Fengguang7c116f22009-12-16 12:19:59 +010092 */
93 if (PageSlab(p))
94 return -EINVAL;
95
96 mapping = page_mapping(p);
97 if (mapping == NULL || mapping->host == NULL)
98 return -EINVAL;
99
100 dev = mapping->host->i_sb->s_dev;
101 if (hwpoison_filter_dev_major != ~0U &&
102 hwpoison_filter_dev_major != MAJOR(dev))
103 return -EINVAL;
104 if (hwpoison_filter_dev_minor != ~0U &&
105 hwpoison_filter_dev_minor != MINOR(dev))
106 return -EINVAL;
107
108 return 0;
109}
110
Wu Fengguang478c5ff2009-12-16 12:19:59 +0100111static int hwpoison_filter_flags(struct page *p)
112{
113 if (!hwpoison_filter_flags_mask)
114 return 0;
115
116 if ((stable_page_flags(p) & hwpoison_filter_flags_mask) ==
117 hwpoison_filter_flags_value)
118 return 0;
119 else
120 return -EINVAL;
121}
122
Andi Kleen4fd466e2009-12-16 12:19:59 +0100123/*
124 * This allows stress tests to limit test scope to a collection of tasks
125 * by putting them under some memcg. This prevents killing unrelated/important
126 * processes such as /sbin/init. Note that the target task may share clean
127 * pages with init (eg. libc text), which is harmless. If the target task
128 * share _dirty_ pages with another task B, the test scheme must make sure B
129 * is also included in the memcg. At last, due to race conditions this filter
130 * can only guarantee that the page either belongs to the memcg tasks, or is
131 * a freed page.
132 */
Andrew Mortonc255a452012-07-31 16:43:02 -0700133#ifdef CONFIG_MEMCG_SWAP
Andi Kleen4fd466e2009-12-16 12:19:59 +0100134u64 hwpoison_filter_memcg;
135EXPORT_SYMBOL_GPL(hwpoison_filter_memcg);
136static int hwpoison_filter_task(struct page *p)
137{
138 struct mem_cgroup *mem;
139 struct cgroup_subsys_state *css;
140 unsigned long ino;
141
142 if (!hwpoison_filter_memcg)
143 return 0;
144
145 mem = try_get_mem_cgroup_from_page(p);
146 if (!mem)
147 return -EINVAL;
148
149 css = mem_cgroup_css(mem);
Tejun Heob1664922014-02-11 11:52:49 -0500150 ino = cgroup_ino(css->cgroup);
Andi Kleen4fd466e2009-12-16 12:19:59 +0100151 css_put(css);
152
Zefan Lif29374b2014-09-19 16:29:31 +0800153 if (ino != hwpoison_filter_memcg)
Andi Kleen4fd466e2009-12-16 12:19:59 +0100154 return -EINVAL;
155
156 return 0;
157}
158#else
159static int hwpoison_filter_task(struct page *p) { return 0; }
160#endif
161
Wu Fengguang7c116f22009-12-16 12:19:59 +0100162int hwpoison_filter(struct page *p)
163{
Haicheng Li1bfe5fe2009-12-16 12:19:59 +0100164 if (!hwpoison_filter_enable)
165 return 0;
166
Wu Fengguang7c116f22009-12-16 12:19:59 +0100167 if (hwpoison_filter_dev(p))
168 return -EINVAL;
169
Wu Fengguang478c5ff2009-12-16 12:19:59 +0100170 if (hwpoison_filter_flags(p))
171 return -EINVAL;
172
Andi Kleen4fd466e2009-12-16 12:19:59 +0100173 if (hwpoison_filter_task(p))
174 return -EINVAL;
175
Wu Fengguang7c116f22009-12-16 12:19:59 +0100176 return 0;
177}
Andi Kleen27df5062009-12-21 19:56:42 +0100178#else
179int hwpoison_filter(struct page *p)
180{
181 return 0;
182}
183#endif
184
Wu Fengguang7c116f22009-12-16 12:19:59 +0100185EXPORT_SYMBOL_GPL(hwpoison_filter);
186
Andi Kleen6a460792009-09-16 11:50:15 +0200187/*
Tony Luck7329bbe2011-12-13 09:27:58 -0800188 * Send all the processes who have the page mapped a signal.
189 * ``action optional'' if they are not immediately affected by the error
190 * ``action required'' if error happened in current execution context
Andi Kleen6a460792009-09-16 11:50:15 +0200191 */
Tony Luck7329bbe2011-12-13 09:27:58 -0800192static int kill_proc(struct task_struct *t, unsigned long addr, int trapno,
193 unsigned long pfn, struct page *page, int flags)
Andi Kleen6a460792009-09-16 11:50:15 +0200194{
195 struct siginfo si;
196 int ret;
197
198 printk(KERN_ERR
Tony Luck7329bbe2011-12-13 09:27:58 -0800199 "MCE %#lx: Killing %s:%d due to hardware memory corruption\n",
Andi Kleen6a460792009-09-16 11:50:15 +0200200 pfn, t->comm, t->pid);
201 si.si_signo = SIGBUS;
202 si.si_errno = 0;
Andi Kleen6a460792009-09-16 11:50:15 +0200203 si.si_addr = (void *)addr;
204#ifdef __ARCH_SI_TRAPNO
205 si.si_trapno = trapno;
206#endif
Wanpeng Lif9121152013-09-11 14:22:52 -0700207 si.si_addr_lsb = compound_order(compound_head(page)) + PAGE_SHIFT;
Tony Luck7329bbe2011-12-13 09:27:58 -0800208
Tony Lucka70ffca2014-06-04 16:10:59 -0700209 if ((flags & MF_ACTION_REQUIRED) && t->mm == current->mm) {
Tony Luck7329bbe2011-12-13 09:27:58 -0800210 si.si_code = BUS_MCEERR_AR;
Tony Lucka70ffca2014-06-04 16:10:59 -0700211 ret = force_sig_info(SIGBUS, &si, current);
Tony Luck7329bbe2011-12-13 09:27:58 -0800212 } else {
213 /*
214 * Don't use force here, it's convenient if the signal
215 * can be temporarily blocked.
216 * This could cause a loop when the user sets SIGBUS
217 * to SIG_IGN, but hopefully no one will do that?
218 */
219 si.si_code = BUS_MCEERR_AO;
220 ret = send_sig_info(SIGBUS, &si, t); /* synchronous? */
221 }
Andi Kleen6a460792009-09-16 11:50:15 +0200222 if (ret < 0)
223 printk(KERN_INFO "MCE: Error sending signal to %s:%d: %d\n",
224 t->comm, t->pid, ret);
225 return ret;
226}
227
228/*
Andi Kleen588f9ce2009-12-16 12:19:57 +0100229 * When a unknown page type is encountered drain as many buffers as possible
230 * in the hope to turn the page into a LRU or free page, which we can handle.
231 */
Andi Kleenfacb6012009-12-16 12:20:00 +0100232void shake_page(struct page *p, int access)
Andi Kleen588f9ce2009-12-16 12:19:57 +0100233{
234 if (!PageSlab(p)) {
235 lru_add_drain_all();
236 if (PageLRU(p))
237 return;
Vlastimil Babkac0554322014-12-10 15:43:10 -0800238 drain_all_pages(page_zone(p));
Andi Kleen588f9ce2009-12-16 12:19:57 +0100239 if (PageLRU(p) || is_free_buddy_page(p))
240 return;
241 }
Andi Kleenfacb6012009-12-16 12:20:00 +0100242
Andi Kleen588f9ce2009-12-16 12:19:57 +0100243 /*
Johannes Weiner6b4f7792014-12-12 16:56:13 -0800244 * Only call shrink_node_slabs here (which would also shrink
245 * other caches) if access is not potentially fatal.
Andi Kleen588f9ce2009-12-16 12:19:57 +0100246 */
Vladimir Davydovcb731d62015-02-12 14:58:54 -0800247 if (access)
248 drop_slab_node(page_to_nid(p));
Andi Kleen588f9ce2009-12-16 12:19:57 +0100249}
250EXPORT_SYMBOL_GPL(shake_page);
251
252/*
Andi Kleen6a460792009-09-16 11:50:15 +0200253 * Kill all processes that have a poisoned page mapped and then isolate
254 * the page.
255 *
256 * General strategy:
257 * Find all processes having the page mapped and kill them.
258 * But we keep a page reference around so that the page is not
259 * actually freed yet.
260 * Then stash the page away
261 *
262 * There's no convenient way to get back to mapped processes
263 * from the VMAs. So do a brute-force search over all
264 * running processes.
265 *
266 * Remember that machine checks are not common (or rather
267 * if they are common you have other problems), so this shouldn't
268 * be a performance issue.
269 *
270 * Also there are some races possible while we get from the
271 * error detection to actually handle it.
272 */
273
274struct to_kill {
275 struct list_head nd;
276 struct task_struct *tsk;
277 unsigned long addr;
Andi Kleen9033ae12010-09-27 23:36:05 +0200278 char addr_valid;
Andi Kleen6a460792009-09-16 11:50:15 +0200279};
280
281/*
282 * Failure handling: if we can't find or can't kill a process there's
283 * not much we can do. We just print a message and ignore otherwise.
284 */
285
286/*
287 * Schedule a process for later kill.
288 * Uses GFP_ATOMIC allocations to avoid potential recursions in the VM.
289 * TBD would GFP_NOIO be enough?
290 */
291static void add_to_kill(struct task_struct *tsk, struct page *p,
292 struct vm_area_struct *vma,
293 struct list_head *to_kill,
294 struct to_kill **tkc)
295{
296 struct to_kill *tk;
297
298 if (*tkc) {
299 tk = *tkc;
300 *tkc = NULL;
301 } else {
302 tk = kmalloc(sizeof(struct to_kill), GFP_ATOMIC);
303 if (!tk) {
304 printk(KERN_ERR
305 "MCE: Out of memory while machine check handling\n");
306 return;
307 }
308 }
309 tk->addr = page_address_in_vma(p, vma);
310 tk->addr_valid = 1;
311
312 /*
313 * In theory we don't have to kill when the page was
314 * munmaped. But it could be also a mremap. Since that's
315 * likely very rare kill anyways just out of paranoia, but use
316 * a SIGKILL because the error is not contained anymore.
317 */
318 if (tk->addr == -EFAULT) {
Andi Kleenfb46e732010-09-27 23:31:30 +0200319 pr_info("MCE: Unable to find user space address %lx in %s\n",
Andi Kleen6a460792009-09-16 11:50:15 +0200320 page_to_pfn(p), tsk->comm);
321 tk->addr_valid = 0;
322 }
323 get_task_struct(tsk);
324 tk->tsk = tsk;
325 list_add_tail(&tk->nd, to_kill);
326}
327
328/*
329 * Kill the processes that have been collected earlier.
330 *
331 * Only do anything when DOIT is set, otherwise just free the list
332 * (this is used for clean pages which do not need killing)
333 * Also when FAIL is set do a force kill because something went
334 * wrong earlier.
335 */
Tony Luck6751ed62012-07-11 10:20:47 -0700336static void kill_procs(struct list_head *to_kill, int forcekill, int trapno,
Tony Luck7329bbe2011-12-13 09:27:58 -0800337 int fail, struct page *page, unsigned long pfn,
338 int flags)
Andi Kleen6a460792009-09-16 11:50:15 +0200339{
340 struct to_kill *tk, *next;
341
342 list_for_each_entry_safe (tk, next, to_kill, nd) {
Tony Luck6751ed62012-07-11 10:20:47 -0700343 if (forcekill) {
Andi Kleen6a460792009-09-16 11:50:15 +0200344 /*
André Goddard Rosaaf901ca2009-11-14 13:09:05 -0200345 * In case something went wrong with munmapping
Andi Kleen6a460792009-09-16 11:50:15 +0200346 * make sure the process doesn't catch the
347 * signal and then access the memory. Just kill it.
Andi Kleen6a460792009-09-16 11:50:15 +0200348 */
349 if (fail || tk->addr_valid == 0) {
350 printk(KERN_ERR
351 "MCE %#lx: forcibly killing %s:%d because of failure to unmap corrupted page\n",
352 pfn, tk->tsk->comm, tk->tsk->pid);
353 force_sig(SIGKILL, tk->tsk);
354 }
355
356 /*
357 * In theory the process could have mapped
358 * something else on the address in-between. We could
359 * check for that, but we need to tell the
360 * process anyways.
361 */
Tony Luck7329bbe2011-12-13 09:27:58 -0800362 else if (kill_proc(tk->tsk, tk->addr, trapno,
363 pfn, page, flags) < 0)
Andi Kleen6a460792009-09-16 11:50:15 +0200364 printk(KERN_ERR
365 "MCE %#lx: Cannot send advisory machine check signal to %s:%d\n",
366 pfn, tk->tsk->comm, tk->tsk->pid);
367 }
368 put_task_struct(tk->tsk);
369 kfree(tk);
370 }
371}
372
Naoya Horiguchi3ba08122014-06-04 16:11:02 -0700373/*
374 * Find a dedicated thread which is supposed to handle SIGBUS(BUS_MCEERR_AO)
375 * on behalf of the thread group. Return task_struct of the (first found)
376 * dedicated thread if found, and return NULL otherwise.
377 *
378 * We already hold read_lock(&tasklist_lock) in the caller, so we don't
379 * have to call rcu_read_lock/unlock() in this function.
380 */
381static struct task_struct *find_early_kill_thread(struct task_struct *tsk)
Andi Kleen6a460792009-09-16 11:50:15 +0200382{
Naoya Horiguchi3ba08122014-06-04 16:11:02 -0700383 struct task_struct *t;
384
385 for_each_thread(tsk, t)
386 if ((t->flags & PF_MCE_PROCESS) && (t->flags & PF_MCE_EARLY))
387 return t;
388 return NULL;
389}
390
391/*
392 * Determine whether a given process is "early kill" process which expects
393 * to be signaled when some page under the process is hwpoisoned.
394 * Return task_struct of the dedicated thread (main thread unless explicitly
395 * specified) if the process is "early kill," and otherwise returns NULL.
396 */
397static struct task_struct *task_early_kill(struct task_struct *tsk,
398 int force_early)
399{
400 struct task_struct *t;
Andi Kleen6a460792009-09-16 11:50:15 +0200401 if (!tsk->mm)
Naoya Horiguchi3ba08122014-06-04 16:11:02 -0700402 return NULL;
Tony Luck74614de2014-06-04 16:11:01 -0700403 if (force_early)
Naoya Horiguchi3ba08122014-06-04 16:11:02 -0700404 return tsk;
405 t = find_early_kill_thread(tsk);
406 if (t)
407 return t;
408 if (sysctl_memory_failure_early_kill)
409 return tsk;
410 return NULL;
Andi Kleen6a460792009-09-16 11:50:15 +0200411}
412
413/*
414 * Collect processes when the error hit an anonymous page.
415 */
416static void collect_procs_anon(struct page *page, struct list_head *to_kill,
Tony Luck74614de2014-06-04 16:11:01 -0700417 struct to_kill **tkc, int force_early)
Andi Kleen6a460792009-09-16 11:50:15 +0200418{
419 struct vm_area_struct *vma;
420 struct task_struct *tsk;
421 struct anon_vma *av;
Michel Lespinassebf181b92012-10-08 16:31:39 -0700422 pgoff_t pgoff;
Andi Kleen6a460792009-09-16 11:50:15 +0200423
Ingo Molnar4fc3f1d2012-12-02 19:56:50 +0000424 av = page_lock_anon_vma_read(page);
Andi Kleen6a460792009-09-16 11:50:15 +0200425 if (av == NULL) /* Not actually mapped anymore */
Peter Zijlstra9b679322011-06-27 16:18:09 -0700426 return;
427
Naoya Horiguchia0f7a752014-07-23 14:00:01 -0700428 pgoff = page_to_pgoff(page);
Peter Zijlstra9b679322011-06-27 16:18:09 -0700429 read_lock(&tasklist_lock);
Andi Kleen6a460792009-09-16 11:50:15 +0200430 for_each_process (tsk) {
Rik van Riel5beb4932010-03-05 13:42:07 -0800431 struct anon_vma_chain *vmac;
Naoya Horiguchi3ba08122014-06-04 16:11:02 -0700432 struct task_struct *t = task_early_kill(tsk, force_early);
Rik van Riel5beb4932010-03-05 13:42:07 -0800433
Naoya Horiguchi3ba08122014-06-04 16:11:02 -0700434 if (!t)
Andi Kleen6a460792009-09-16 11:50:15 +0200435 continue;
Michel Lespinassebf181b92012-10-08 16:31:39 -0700436 anon_vma_interval_tree_foreach(vmac, &av->rb_root,
437 pgoff, pgoff) {
Rik van Riel5beb4932010-03-05 13:42:07 -0800438 vma = vmac->vma;
Andi Kleen6a460792009-09-16 11:50:15 +0200439 if (!page_mapped_in_vma(page, vma))
440 continue;
Naoya Horiguchi3ba08122014-06-04 16:11:02 -0700441 if (vma->vm_mm == t->mm)
442 add_to_kill(t, page, vma, to_kill, tkc);
Andi Kleen6a460792009-09-16 11:50:15 +0200443 }
444 }
Andi Kleen6a460792009-09-16 11:50:15 +0200445 read_unlock(&tasklist_lock);
Ingo Molnar4fc3f1d2012-12-02 19:56:50 +0000446 page_unlock_anon_vma_read(av);
Andi Kleen6a460792009-09-16 11:50:15 +0200447}
448
449/*
450 * Collect processes when the error hit a file mapped page.
451 */
452static void collect_procs_file(struct page *page, struct list_head *to_kill,
Tony Luck74614de2014-06-04 16:11:01 -0700453 struct to_kill **tkc, int force_early)
Andi Kleen6a460792009-09-16 11:50:15 +0200454{
455 struct vm_area_struct *vma;
456 struct task_struct *tsk;
Andi Kleen6a460792009-09-16 11:50:15 +0200457 struct address_space *mapping = page->mapping;
458
Davidlohr Buesod28eb9c2014-12-12 16:54:36 -0800459 i_mmap_lock_read(mapping);
Peter Zijlstra9b679322011-06-27 16:18:09 -0700460 read_lock(&tasklist_lock);
Andi Kleen6a460792009-09-16 11:50:15 +0200461 for_each_process(tsk) {
Naoya Horiguchia0f7a752014-07-23 14:00:01 -0700462 pgoff_t pgoff = page_to_pgoff(page);
Naoya Horiguchi3ba08122014-06-04 16:11:02 -0700463 struct task_struct *t = task_early_kill(tsk, force_early);
Andi Kleen6a460792009-09-16 11:50:15 +0200464
Naoya Horiguchi3ba08122014-06-04 16:11:02 -0700465 if (!t)
Andi Kleen6a460792009-09-16 11:50:15 +0200466 continue;
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700467 vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff,
Andi Kleen6a460792009-09-16 11:50:15 +0200468 pgoff) {
469 /*
470 * Send early kill signal to tasks where a vma covers
471 * the page but the corrupted page is not necessarily
472 * mapped it in its pte.
473 * Assume applications who requested early kill want
474 * to be informed of all such data corruptions.
475 */
Naoya Horiguchi3ba08122014-06-04 16:11:02 -0700476 if (vma->vm_mm == t->mm)
477 add_to_kill(t, page, vma, to_kill, tkc);
Andi Kleen6a460792009-09-16 11:50:15 +0200478 }
479 }
Andi Kleen6a460792009-09-16 11:50:15 +0200480 read_unlock(&tasklist_lock);
Davidlohr Buesod28eb9c2014-12-12 16:54:36 -0800481 i_mmap_unlock_read(mapping);
Andi Kleen6a460792009-09-16 11:50:15 +0200482}
483
484/*
485 * Collect the processes who have the corrupted page mapped to kill.
486 * This is done in two steps for locking reasons.
487 * First preallocate one tokill structure outside the spin locks,
488 * so that we can kill at least one process reasonably reliable.
489 */
Tony Luck74614de2014-06-04 16:11:01 -0700490static void collect_procs(struct page *page, struct list_head *tokill,
491 int force_early)
Andi Kleen6a460792009-09-16 11:50:15 +0200492{
493 struct to_kill *tk;
494
495 if (!page->mapping)
496 return;
497
498 tk = kmalloc(sizeof(struct to_kill), GFP_NOIO);
499 if (!tk)
500 return;
501 if (PageAnon(page))
Tony Luck74614de2014-06-04 16:11:01 -0700502 collect_procs_anon(page, tokill, &tk, force_early);
Andi Kleen6a460792009-09-16 11:50:15 +0200503 else
Tony Luck74614de2014-06-04 16:11:01 -0700504 collect_procs_file(page, tokill, &tk, force_early);
Andi Kleen6a460792009-09-16 11:50:15 +0200505 kfree(tk);
506}
507
Andi Kleen6a460792009-09-16 11:50:15 +0200508static const char *action_name[] = {
Xie XiuQicc637b12015-06-24 16:57:30 -0700509 [MF_IGNORED] = "Ignored",
510 [MF_FAILED] = "Failed",
511 [MF_DELAYED] = "Delayed",
512 [MF_RECOVERED] = "Recovered",
Naoya Horiguchi64d37a22015-04-15 16:13:05 -0700513};
514
515static const char * const action_page_types[] = {
Xie XiuQicc637b12015-06-24 16:57:30 -0700516 [MF_MSG_KERNEL] = "reserved kernel page",
517 [MF_MSG_KERNEL_HIGH_ORDER] = "high-order kernel page",
518 [MF_MSG_SLAB] = "kernel slab page",
519 [MF_MSG_DIFFERENT_COMPOUND] = "different compound page after locking",
520 [MF_MSG_POISONED_HUGE] = "huge page already hardware poisoned",
521 [MF_MSG_HUGE] = "huge page",
522 [MF_MSG_FREE_HUGE] = "free huge page",
523 [MF_MSG_UNMAP_FAILED] = "unmapping failed page",
524 [MF_MSG_DIRTY_SWAPCACHE] = "dirty swapcache page",
525 [MF_MSG_CLEAN_SWAPCACHE] = "clean swapcache page",
526 [MF_MSG_DIRTY_MLOCKED_LRU] = "dirty mlocked LRU page",
527 [MF_MSG_CLEAN_MLOCKED_LRU] = "clean mlocked LRU page",
528 [MF_MSG_DIRTY_UNEVICTABLE_LRU] = "dirty unevictable LRU page",
529 [MF_MSG_CLEAN_UNEVICTABLE_LRU] = "clean unevictable LRU page",
530 [MF_MSG_DIRTY_LRU] = "dirty LRU page",
531 [MF_MSG_CLEAN_LRU] = "clean LRU page",
532 [MF_MSG_TRUNCATED_LRU] = "already truncated LRU page",
533 [MF_MSG_BUDDY] = "free buddy page",
534 [MF_MSG_BUDDY_2ND] = "free buddy page (2nd try)",
535 [MF_MSG_UNKNOWN] = "unknown page",
Naoya Horiguchi64d37a22015-04-15 16:13:05 -0700536};
537
Andi Kleen6a460792009-09-16 11:50:15 +0200538/*
Wu Fengguangdc2a1cb2009-12-16 12:19:58 +0100539 * XXX: It is possible that a page is isolated from LRU cache,
540 * and then kept in swap cache or failed to remove from page cache.
541 * The page count will stop it from being freed by unpoison.
542 * Stress tests should be aware of this memory leak problem.
543 */
544static int delete_from_lru_cache(struct page *p)
545{
546 if (!isolate_lru_page(p)) {
547 /*
548 * Clear sensible page flags, so that the buddy system won't
549 * complain when the page is unpoison-and-freed.
550 */
551 ClearPageActive(p);
552 ClearPageUnevictable(p);
553 /*
554 * drop the page count elevated by isolate_lru_page()
555 */
556 page_cache_release(p);
557 return 0;
558 }
559 return -EIO;
560}
561
562/*
Andi Kleen6a460792009-09-16 11:50:15 +0200563 * Error hit kernel page.
564 * Do nothing, try to be lucky and not touch this instead. For a few cases we
565 * could be more sophisticated.
566 */
567static int me_kernel(struct page *p, unsigned long pfn)
568{
Xie XiuQicc637b12015-06-24 16:57:30 -0700569 return MF_IGNORED;
Andi Kleen6a460792009-09-16 11:50:15 +0200570}
571
572/*
573 * Page in unknown state. Do nothing.
574 */
575static int me_unknown(struct page *p, unsigned long pfn)
576{
577 printk(KERN_ERR "MCE %#lx: Unknown page state\n", pfn);
Xie XiuQicc637b12015-06-24 16:57:30 -0700578 return MF_FAILED;
Andi Kleen6a460792009-09-16 11:50:15 +0200579}
580
581/*
Andi Kleen6a460792009-09-16 11:50:15 +0200582 * Clean (or cleaned) page cache page.
583 */
584static int me_pagecache_clean(struct page *p, unsigned long pfn)
585{
586 int err;
Xie XiuQicc637b12015-06-24 16:57:30 -0700587 int ret = MF_FAILED;
Andi Kleen6a460792009-09-16 11:50:15 +0200588 struct address_space *mapping;
589
Wu Fengguangdc2a1cb2009-12-16 12:19:58 +0100590 delete_from_lru_cache(p);
591
Andi Kleen6a460792009-09-16 11:50:15 +0200592 /*
593 * For anonymous pages we're done the only reference left
594 * should be the one m_f() holds.
595 */
596 if (PageAnon(p))
Xie XiuQicc637b12015-06-24 16:57:30 -0700597 return MF_RECOVERED;
Andi Kleen6a460792009-09-16 11:50:15 +0200598
599 /*
600 * Now truncate the page in the page cache. This is really
601 * more like a "temporary hole punch"
602 * Don't do this for block devices when someone else
603 * has a reference, because it could be file system metadata
604 * and that's not safe to truncate.
605 */
606 mapping = page_mapping(p);
607 if (!mapping) {
608 /*
609 * Page has been teared down in the meanwhile
610 */
Xie XiuQicc637b12015-06-24 16:57:30 -0700611 return MF_FAILED;
Andi Kleen6a460792009-09-16 11:50:15 +0200612 }
613
614 /*
615 * Truncation is a bit tricky. Enable it per file system for now.
616 *
617 * Open: to take i_mutex or not for this? Right now we don't.
618 */
619 if (mapping->a_ops->error_remove_page) {
620 err = mapping->a_ops->error_remove_page(mapping, p);
621 if (err != 0) {
622 printk(KERN_INFO "MCE %#lx: Failed to punch page: %d\n",
623 pfn, err);
624 } else if (page_has_private(p) &&
625 !try_to_release_page(p, GFP_NOIO)) {
Andi Kleenfb46e732010-09-27 23:31:30 +0200626 pr_info("MCE %#lx: failed to release buffers\n", pfn);
Andi Kleen6a460792009-09-16 11:50:15 +0200627 } else {
Xie XiuQicc637b12015-06-24 16:57:30 -0700628 ret = MF_RECOVERED;
Andi Kleen6a460792009-09-16 11:50:15 +0200629 }
630 } else {
631 /*
632 * If the file system doesn't support it just invalidate
633 * This fails on dirty or anything with private pages
634 */
635 if (invalidate_inode_page(p))
Xie XiuQicc637b12015-06-24 16:57:30 -0700636 ret = MF_RECOVERED;
Andi Kleen6a460792009-09-16 11:50:15 +0200637 else
638 printk(KERN_INFO "MCE %#lx: Failed to invalidate\n",
639 pfn);
640 }
641 return ret;
642}
643
644/*
Zhi Yong Wu549543d2014-01-21 15:49:08 -0800645 * Dirty pagecache page
Andi Kleen6a460792009-09-16 11:50:15 +0200646 * Issues: when the error hit a hole page the error is not properly
647 * propagated.
648 */
649static int me_pagecache_dirty(struct page *p, unsigned long pfn)
650{
651 struct address_space *mapping = page_mapping(p);
652
653 SetPageError(p);
654 /* TBD: print more information about the file. */
655 if (mapping) {
656 /*
657 * IO error will be reported by write(), fsync(), etc.
658 * who check the mapping.
659 * This way the application knows that something went
660 * wrong with its dirty file data.
661 *
662 * There's one open issue:
663 *
664 * The EIO will be only reported on the next IO
665 * operation and then cleared through the IO map.
666 * Normally Linux has two mechanisms to pass IO error
667 * first through the AS_EIO flag in the address space
668 * and then through the PageError flag in the page.
669 * Since we drop pages on memory failure handling the
670 * only mechanism open to use is through AS_AIO.
671 *
672 * This has the disadvantage that it gets cleared on
673 * the first operation that returns an error, while
674 * the PageError bit is more sticky and only cleared
675 * when the page is reread or dropped. If an
676 * application assumes it will always get error on
677 * fsync, but does other operations on the fd before
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300678 * and the page is dropped between then the error
Andi Kleen6a460792009-09-16 11:50:15 +0200679 * will not be properly reported.
680 *
681 * This can already happen even without hwpoisoned
682 * pages: first on metadata IO errors (which only
683 * report through AS_EIO) or when the page is dropped
684 * at the wrong time.
685 *
686 * So right now we assume that the application DTRT on
687 * the first EIO, but we're not worse than other parts
688 * of the kernel.
689 */
690 mapping_set_error(mapping, EIO);
691 }
692
693 return me_pagecache_clean(p, pfn);
694}
695
696/*
697 * Clean and dirty swap cache.
698 *
699 * Dirty swap cache page is tricky to handle. The page could live both in page
700 * cache and swap cache(ie. page is freshly swapped in). So it could be
701 * referenced concurrently by 2 types of PTEs:
702 * normal PTEs and swap PTEs. We try to handle them consistently by calling
703 * try_to_unmap(TTU_IGNORE_HWPOISON) to convert the normal PTEs to swap PTEs,
704 * and then
705 * - clear dirty bit to prevent IO
706 * - remove from LRU
707 * - but keep in the swap cache, so that when we return to it on
708 * a later page fault, we know the application is accessing
709 * corrupted data and shall be killed (we installed simple
710 * interception code in do_swap_page to catch it).
711 *
712 * Clean swap cache pages can be directly isolated. A later page fault will
713 * bring in the known good data from disk.
714 */
715static int me_swapcache_dirty(struct page *p, unsigned long pfn)
716{
Andi Kleen6a460792009-09-16 11:50:15 +0200717 ClearPageDirty(p);
718 /* Trigger EIO in shmem: */
719 ClearPageUptodate(p);
720
Wu Fengguangdc2a1cb2009-12-16 12:19:58 +0100721 if (!delete_from_lru_cache(p))
Xie XiuQicc637b12015-06-24 16:57:30 -0700722 return MF_DELAYED;
Wu Fengguangdc2a1cb2009-12-16 12:19:58 +0100723 else
Xie XiuQicc637b12015-06-24 16:57:30 -0700724 return MF_FAILED;
Andi Kleen6a460792009-09-16 11:50:15 +0200725}
726
727static int me_swapcache_clean(struct page *p, unsigned long pfn)
728{
Andi Kleen6a460792009-09-16 11:50:15 +0200729 delete_from_swap_cache(p);
Wu Fengguange43c3af2009-09-29 13:16:20 +0800730
Wu Fengguangdc2a1cb2009-12-16 12:19:58 +0100731 if (!delete_from_lru_cache(p))
Xie XiuQicc637b12015-06-24 16:57:30 -0700732 return MF_RECOVERED;
Wu Fengguangdc2a1cb2009-12-16 12:19:58 +0100733 else
Xie XiuQicc637b12015-06-24 16:57:30 -0700734 return MF_FAILED;
Andi Kleen6a460792009-09-16 11:50:15 +0200735}
736
737/*
738 * Huge pages. Needs work.
739 * Issues:
Naoya Horiguchi93f70f92010-05-28 09:29:20 +0900740 * - Error on hugepage is contained in hugepage unit (not in raw page unit.)
741 * To narrow down kill region to one page, we need to break up pmd.
Andi Kleen6a460792009-09-16 11:50:15 +0200742 */
743static int me_huge_page(struct page *p, unsigned long pfn)
744{
Naoya Horiguchi6de2b1a2010-09-08 10:19:36 +0900745 int res = 0;
Naoya Horiguchi93f70f92010-05-28 09:29:20 +0900746 struct page *hpage = compound_head(p);
Naoya Horiguchi2491ffe2015-06-24 16:56:53 -0700747
748 if (!PageHuge(hpage))
749 return MF_DELAYED;
750
Naoya Horiguchi93f70f92010-05-28 09:29:20 +0900751 /*
752 * We can safely recover from error on free or reserved (i.e.
753 * not in-use) hugepage by dequeuing it from freelist.
754 * To check whether a hugepage is in-use or not, we can't use
755 * page->lru because it can be used in other hugepage operations,
756 * such as __unmap_hugepage_range() and gather_surplus_pages().
757 * So instead we use page_mapping() and PageAnon().
758 * We assume that this function is called with page lock held,
759 * so there is no race between isolation and mapping/unmapping.
760 */
761 if (!(page_mapping(hpage) || PageAnon(hpage))) {
Naoya Horiguchi6de2b1a2010-09-08 10:19:36 +0900762 res = dequeue_hwpoisoned_huge_page(hpage);
763 if (!res)
Xie XiuQicc637b12015-06-24 16:57:30 -0700764 return MF_RECOVERED;
Naoya Horiguchi93f70f92010-05-28 09:29:20 +0900765 }
Xie XiuQicc637b12015-06-24 16:57:30 -0700766 return MF_DELAYED;
Andi Kleen6a460792009-09-16 11:50:15 +0200767}
768
769/*
770 * Various page states we can handle.
771 *
772 * A page state is defined by its current page->flags bits.
773 * The table matches them in order and calls the right handler.
774 *
775 * This is quite tricky because we can access page at any time
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300776 * in its live cycle, so all accesses have to be extremely careful.
Andi Kleen6a460792009-09-16 11:50:15 +0200777 *
778 * This is not complete. More states could be added.
779 * For any missing state don't attempt recovery.
780 */
781
782#define dirty (1UL << PG_dirty)
783#define sc (1UL << PG_swapcache)
784#define unevict (1UL << PG_unevictable)
785#define mlock (1UL << PG_mlocked)
786#define writeback (1UL << PG_writeback)
787#define lru (1UL << PG_lru)
788#define swapbacked (1UL << PG_swapbacked)
789#define head (1UL << PG_head)
790#define tail (1UL << PG_tail)
791#define compound (1UL << PG_compound)
792#define slab (1UL << PG_slab)
Andi Kleen6a460792009-09-16 11:50:15 +0200793#define reserved (1UL << PG_reserved)
794
795static struct page_state {
796 unsigned long mask;
797 unsigned long res;
Xie XiuQicc637b12015-06-24 16:57:30 -0700798 enum mf_action_page_type type;
Andi Kleen6a460792009-09-16 11:50:15 +0200799 int (*action)(struct page *p, unsigned long pfn);
800} error_states[] = {
Xie XiuQicc637b12015-06-24 16:57:30 -0700801 { reserved, reserved, MF_MSG_KERNEL, me_kernel },
Wu Fengguang95d01fc2009-12-16 12:19:58 +0100802 /*
803 * free pages are specially detected outside this table:
804 * PG_buddy pages only make a small fraction of all free pages.
805 */
Andi Kleen6a460792009-09-16 11:50:15 +0200806
807 /*
808 * Could in theory check if slab page is free or if we can drop
809 * currently unused objects without touching them. But just
810 * treat it as standard kernel for now.
811 */
Xie XiuQicc637b12015-06-24 16:57:30 -0700812 { slab, slab, MF_MSG_SLAB, me_kernel },
Andi Kleen6a460792009-09-16 11:50:15 +0200813
814#ifdef CONFIG_PAGEFLAGS_EXTENDED
Xie XiuQicc637b12015-06-24 16:57:30 -0700815 { head, head, MF_MSG_HUGE, me_huge_page },
816 { tail, tail, MF_MSG_HUGE, me_huge_page },
Andi Kleen6a460792009-09-16 11:50:15 +0200817#else
Xie XiuQicc637b12015-06-24 16:57:30 -0700818 { compound, compound, MF_MSG_HUGE, me_huge_page },
Andi Kleen6a460792009-09-16 11:50:15 +0200819#endif
820
Xie XiuQicc637b12015-06-24 16:57:30 -0700821 { sc|dirty, sc|dirty, MF_MSG_DIRTY_SWAPCACHE, me_swapcache_dirty },
822 { sc|dirty, sc, MF_MSG_CLEAN_SWAPCACHE, me_swapcache_clean },
Andi Kleen6a460792009-09-16 11:50:15 +0200823
Xie XiuQicc637b12015-06-24 16:57:30 -0700824 { mlock|dirty, mlock|dirty, MF_MSG_DIRTY_MLOCKED_LRU, me_pagecache_dirty },
825 { mlock|dirty, mlock, MF_MSG_CLEAN_MLOCKED_LRU, me_pagecache_clean },
Andi Kleen6a460792009-09-16 11:50:15 +0200826
Xie XiuQicc637b12015-06-24 16:57:30 -0700827 { unevict|dirty, unevict|dirty, MF_MSG_DIRTY_UNEVICTABLE_LRU, me_pagecache_dirty },
828 { unevict|dirty, unevict, MF_MSG_CLEAN_UNEVICTABLE_LRU, me_pagecache_clean },
Naoya Horiguchi5f4b9fc2013-02-22 16:35:53 -0800829
Xie XiuQicc637b12015-06-24 16:57:30 -0700830 { lru|dirty, lru|dirty, MF_MSG_DIRTY_LRU, me_pagecache_dirty },
831 { lru|dirty, lru, MF_MSG_CLEAN_LRU, me_pagecache_clean },
Andi Kleen6a460792009-09-16 11:50:15 +0200832
833 /*
834 * Catchall entry: must be at end.
835 */
Xie XiuQicc637b12015-06-24 16:57:30 -0700836 { 0, 0, MF_MSG_UNKNOWN, me_unknown },
Andi Kleen6a460792009-09-16 11:50:15 +0200837};
838
Andi Kleen2326c462009-12-16 12:20:00 +0100839#undef dirty
840#undef sc
841#undef unevict
842#undef mlock
843#undef writeback
844#undef lru
845#undef swapbacked
846#undef head
847#undef tail
848#undef compound
849#undef slab
850#undef reserved
851
Naoya Horiguchiff604cf2012-12-11 16:01:32 -0800852/*
853 * "Dirty/Clean" indication is not 100% accurate due to the possibility of
854 * setting PG_dirty outside page lock. See also comment above set_page_dirty().
855 */
Xie XiuQicc3e2af2015-06-24 16:57:33 -0700856static void action_result(unsigned long pfn, enum mf_action_page_type type,
857 enum mf_result result)
Andi Kleen6a460792009-09-16 11:50:15 +0200858{
Xie XiuQi97f0b132015-06-24 16:57:36 -0700859 trace_memory_failure_event(pfn, type, result);
860
Naoya Horiguchi64d37a22015-04-15 16:13:05 -0700861 pr_err("MCE %#lx: recovery action for %s: %s\n",
862 pfn, action_page_types[type], action_name[result]);
Andi Kleen6a460792009-09-16 11:50:15 +0200863}
864
865static int page_action(struct page_state *ps, struct page *p,
Wu Fengguangbd1ce5f2009-12-16 12:19:57 +0100866 unsigned long pfn)
Andi Kleen6a460792009-09-16 11:50:15 +0200867{
868 int result;
Wu Fengguang7456b042009-10-19 08:15:01 +0200869 int count;
Andi Kleen6a460792009-09-16 11:50:15 +0200870
871 result = ps->action(p, pfn);
Wu Fengguang7456b042009-10-19 08:15:01 +0200872
Wu Fengguangbd1ce5f2009-12-16 12:19:57 +0100873 count = page_count(p) - 1;
Xie XiuQicc637b12015-06-24 16:57:30 -0700874 if (ps->action == me_swapcache_dirty && result == MF_DELAYED)
Wu Fengguang138ce282009-12-16 12:19:58 +0100875 count--;
876 if (count != 0) {
Andi Kleen6a460792009-09-16 11:50:15 +0200877 printk(KERN_ERR
Naoya Horiguchi64d37a22015-04-15 16:13:05 -0700878 "MCE %#lx: %s still referenced by %d users\n",
879 pfn, action_page_types[ps->type], count);
Xie XiuQicc637b12015-06-24 16:57:30 -0700880 result = MF_FAILED;
Wu Fengguang138ce282009-12-16 12:19:58 +0100881 }
Naoya Horiguchi64d37a22015-04-15 16:13:05 -0700882 action_result(pfn, ps->type, result);
Andi Kleen6a460792009-09-16 11:50:15 +0200883
884 /* Could do more checks here if page looks ok */
885 /*
886 * Could adjust zone counters here to correct for the missing page.
887 */
888
Xie XiuQicc637b12015-06-24 16:57:30 -0700889 return (result == MF_RECOVERED || result == MF_DELAYED) ? 0 : -EBUSY;
Andi Kleen6a460792009-09-16 11:50:15 +0200890}
891
Naoya Horiguchiead07f62015-06-24 16:56:48 -0700892/**
893 * get_hwpoison_page() - Get refcount for memory error handling:
894 * @page: raw error page (hit by memory error)
895 *
896 * Return: return 0 if failed to grab the refcount, otherwise true (some
897 * non-zero value.)
898 */
899int get_hwpoison_page(struct page *page)
900{
901 struct page *head = compound_head(page);
902
903 if (PageHuge(head))
904 return get_page_unless_zero(head);
905
906 /*
907 * Thp tail page has special refcounting rule (refcount of tail pages
908 * is stored in ->_mapcount,) so we can't call get_page_unless_zero()
909 * directly for tail pages.
910 */
911 if (PageTransHuge(head)) {
912 if (get_page_unless_zero(head)) {
913 if (PageTail(page))
914 get_page(page);
915 return 1;
916 } else {
917 return 0;
918 }
919 }
920
921 return get_page_unless_zero(page);
922}
923EXPORT_SYMBOL_GPL(get_hwpoison_page);
924
Andi Kleen6a460792009-09-16 11:50:15 +0200925/*
926 * Do all that is necessary to remove user space mappings. Unmap
927 * the pages and send SIGBUS to the processes if the data was dirty.
928 */
Wu Fengguang1668bfd2009-12-16 12:19:58 +0100929static int hwpoison_user_mappings(struct page *p, unsigned long pfn,
Naoya Horiguchi54b9dd12014-01-23 15:53:14 -0800930 int trapno, int flags, struct page **hpagep)
Andi Kleen6a460792009-09-16 11:50:15 +0200931{
932 enum ttu_flags ttu = TTU_UNMAP | TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS;
933 struct address_space *mapping;
934 LIST_HEAD(tokill);
935 int ret;
Tony Luck6751ed62012-07-11 10:20:47 -0700936 int kill = 1, forcekill;
Naoya Horiguchi54b9dd12014-01-23 15:53:14 -0800937 struct page *hpage = *hpagep;
Andi Kleen6a460792009-09-16 11:50:15 +0200938
Naoya Horiguchi93a9eb32014-07-30 16:08:28 -0700939 /*
940 * Here we are interested only in user-mapped pages, so skip any
941 * other types of pages.
942 */
943 if (PageReserved(p) || PageSlab(p))
944 return SWAP_SUCCESS;
945 if (!(PageLRU(hpage) || PageHuge(p)))
Wu Fengguang1668bfd2009-12-16 12:19:58 +0100946 return SWAP_SUCCESS;
Andi Kleen6a460792009-09-16 11:50:15 +0200947
Andi Kleen6a460792009-09-16 11:50:15 +0200948 /*
949 * This check implies we don't kill processes if their pages
950 * are in the swap cache early. Those are always late kills.
951 */
Naoya Horiguchi7af446a2010-05-28 09:29:17 +0900952 if (!page_mapped(hpage))
Wu Fengguang1668bfd2009-12-16 12:19:58 +0100953 return SWAP_SUCCESS;
954
Naoya Horiguchi52089b12014-07-30 16:08:30 -0700955 if (PageKsm(p)) {
956 pr_err("MCE %#lx: can't handle KSM pages.\n", pfn);
Wu Fengguang1668bfd2009-12-16 12:19:58 +0100957 return SWAP_FAIL;
Naoya Horiguchi52089b12014-07-30 16:08:30 -0700958 }
Andi Kleen6a460792009-09-16 11:50:15 +0200959
960 if (PageSwapCache(p)) {
961 printk(KERN_ERR
962 "MCE %#lx: keeping poisoned page in swap cache\n", pfn);
963 ttu |= TTU_IGNORE_HWPOISON;
964 }
965
966 /*
967 * Propagate the dirty bit from PTEs to struct page first, because we
968 * need this to decide if we should kill or just drop the page.
Wu Fengguangdb0480b2009-12-16 12:19:58 +0100969 * XXX: the dirty test could be racy: set_page_dirty() may not always
970 * be called inside page lock (it's recommended but not enforced).
Andi Kleen6a460792009-09-16 11:50:15 +0200971 */
Naoya Horiguchi7af446a2010-05-28 09:29:17 +0900972 mapping = page_mapping(hpage);
Tony Luck6751ed62012-07-11 10:20:47 -0700973 if (!(flags & MF_MUST_KILL) && !PageDirty(hpage) && mapping &&
Naoya Horiguchi7af446a2010-05-28 09:29:17 +0900974 mapping_cap_writeback_dirty(mapping)) {
975 if (page_mkclean(hpage)) {
976 SetPageDirty(hpage);
Andi Kleen6a460792009-09-16 11:50:15 +0200977 } else {
978 kill = 0;
979 ttu |= TTU_IGNORE_HWPOISON;
980 printk(KERN_INFO
981 "MCE %#lx: corrupted page was clean: dropped without side effects\n",
982 pfn);
983 }
984 }
985
Jin Dongminga6d30dd2011-02-01 15:52:40 -0800986 /*
Andi Kleen6a460792009-09-16 11:50:15 +0200987 * First collect all the processes that have the page
988 * mapped in dirty form. This has to be done before try_to_unmap,
989 * because ttu takes the rmap data structures down.
990 *
991 * Error handling: We ignore errors here because
992 * there's nothing that can be done.
993 */
994 if (kill)
Naoya Horiguchi415c64c2015-06-24 16:56:45 -0700995 collect_procs(hpage, &tokill, flags & MF_ACTION_REQUIRED);
Andi Kleen6a460792009-09-16 11:50:15 +0200996
Naoya Horiguchi415c64c2015-06-24 16:56:45 -0700997 ret = try_to_unmap(hpage, ttu);
Andi Kleen6a460792009-09-16 11:50:15 +0200998 if (ret != SWAP_SUCCESS)
999 printk(KERN_ERR "MCE %#lx: failed to unmap page (mapcount=%d)\n",
Naoya Horiguchi415c64c2015-06-24 16:56:45 -07001000 pfn, page_mapcount(hpage));
Jin Dongminga6d30dd2011-02-01 15:52:40 -08001001
Andi Kleen6a460792009-09-16 11:50:15 +02001002 /*
1003 * Now that the dirty bit has been propagated to the
1004 * struct page and all unmaps done we can decide if
1005 * killing is needed or not. Only kill when the page
Tony Luck6751ed62012-07-11 10:20:47 -07001006 * was dirty or the process is not restartable,
1007 * otherwise the tokill list is merely
Andi Kleen6a460792009-09-16 11:50:15 +02001008 * freed. When there was a problem unmapping earlier
1009 * use a more force-full uncatchable kill to prevent
1010 * any accesses to the poisoned memory.
1011 */
Naoya Horiguchi415c64c2015-06-24 16:56:45 -07001012 forcekill = PageDirty(hpage) || (flags & MF_MUST_KILL);
Tony Luck6751ed62012-07-11 10:20:47 -07001013 kill_procs(&tokill, forcekill, trapno,
Tony Luck7329bbe2011-12-13 09:27:58 -08001014 ret != SWAP_SUCCESS, p, pfn, flags);
Wu Fengguang1668bfd2009-12-16 12:19:58 +01001015
1016 return ret;
Andi Kleen6a460792009-09-16 11:50:15 +02001017}
1018
Naoya Horiguchi7013feb2010-05-28 09:29:18 +09001019static void set_page_hwpoison_huge_page(struct page *hpage)
1020{
1021 int i;
Wanpeng Lif9121152013-09-11 14:22:52 -07001022 int nr_pages = 1 << compound_order(hpage);
Naoya Horiguchi7013feb2010-05-28 09:29:18 +09001023 for (i = 0; i < nr_pages; i++)
1024 SetPageHWPoison(hpage + i);
1025}
1026
1027static void clear_page_hwpoison_huge_page(struct page *hpage)
1028{
1029 int i;
Wanpeng Lif9121152013-09-11 14:22:52 -07001030 int nr_pages = 1 << compound_order(hpage);
Naoya Horiguchi7013feb2010-05-28 09:29:18 +09001031 for (i = 0; i < nr_pages; i++)
1032 ClearPageHWPoison(hpage + i);
1033}
1034
Tony Luckcd42f4a2011-12-15 10:48:12 -08001035/**
1036 * memory_failure - Handle memory failure of a page.
1037 * @pfn: Page Number of the corrupted page
1038 * @trapno: Trap number reported in the signal to user space.
1039 * @flags: fine tune action taken
1040 *
1041 * This function is called by the low level machine check code
1042 * of an architecture when it detects hardware memory corruption
1043 * of a page. It tries its best to recover, which includes
1044 * dropping pages, killing processes etc.
1045 *
1046 * The function is primarily of use for corruptions that
1047 * happen outside the current execution context (e.g. when
1048 * detected by a background scrubber)
1049 *
1050 * Must run in process context (e.g. a work queue) with interrupts
1051 * enabled and no spinlocks hold.
1052 */
1053int memory_failure(unsigned long pfn, int trapno, int flags)
Andi Kleen6a460792009-09-16 11:50:15 +02001054{
1055 struct page_state *ps;
1056 struct page *p;
Naoya Horiguchi7af446a2010-05-28 09:29:17 +09001057 struct page *hpage;
Naoya Horiguchi415c64c2015-06-24 16:56:45 -07001058 struct page *orig_head;
Andi Kleen6a460792009-09-16 11:50:15 +02001059 int res;
Naoya Horiguchic9fbdd52010-05-28 09:29:19 +09001060 unsigned int nr_pages;
Naoya Horiguchi524fca12013-02-22 16:35:51 -08001061 unsigned long page_flags;
Andi Kleen6a460792009-09-16 11:50:15 +02001062
1063 if (!sysctl_memory_failure_recovery)
1064 panic("Memory failure from trap %d on page %lx", trapno, pfn);
1065
1066 if (!pfn_valid(pfn)) {
Wu Fengguanga7560fc2009-12-16 12:19:57 +01001067 printk(KERN_ERR
1068 "MCE %#lx: memory outside kernel control\n",
1069 pfn);
1070 return -ENXIO;
Andi Kleen6a460792009-09-16 11:50:15 +02001071 }
1072
1073 p = pfn_to_page(pfn);
Naoya Horiguchi415c64c2015-06-24 16:56:45 -07001074 orig_head = hpage = compound_head(p);
Andi Kleen6a460792009-09-16 11:50:15 +02001075 if (TestSetPageHWPoison(p)) {
Wu Fengguangd95ea512009-12-16 12:19:58 +01001076 printk(KERN_ERR "MCE %#lx: already hardware poisoned\n", pfn);
Andi Kleen6a460792009-09-16 11:50:15 +02001077 return 0;
1078 }
1079
Naoya Horiguchi4db0e952013-02-22 16:34:05 -08001080 /*
1081 * Currently errors on hugetlbfs pages are measured in hugepage units,
1082 * so nr_pages should be 1 << compound_order. OTOH when errors are on
1083 * transparent hugepages, they are supposed to be split and error
1084 * measurement is done in normal page units. So nr_pages should be one
1085 * in this case.
1086 */
1087 if (PageHuge(p))
1088 nr_pages = 1 << compound_order(hpage);
1089 else /* normal page or thp */
1090 nr_pages = 1;
Xishi Qiu293c07e2013-02-22 16:34:02 -08001091 atomic_long_add(nr_pages, &num_poisoned_pages);
Andi Kleen6a460792009-09-16 11:50:15 +02001092
1093 /*
1094 * We need/can do nothing about count=0 pages.
1095 * 1) it's a free page, and therefore in safe hand:
1096 * prep_new_page() will be the gate keeper.
Naoya Horiguchi8c6c2ec2010-09-08 10:19:38 +09001097 * 2) it's a free hugepage, which is also safe:
1098 * an affected hugepage will be dequeued from hugepage freelist,
1099 * so there's no concern about reusing it ever after.
1100 * 3) it's part of a non-compound high order page.
Andi Kleen6a460792009-09-16 11:50:15 +02001101 * Implies some kernel user: cannot stop them from
1102 * R/W the page; let's pray that the page has been
1103 * used and will be freed some time later.
1104 * In fact it's dangerous to directly bump up page count from 0,
1105 * that may make page_freeze_refs()/page_unfreeze_refs() mismatch.
1106 */
Naoya Horiguchiead07f62015-06-24 16:56:48 -07001107 if (!(flags & MF_COUNT_INCREASED) && !get_hwpoison_page(p)) {
Wu Fengguang8d22ba12009-12-16 12:19:58 +01001108 if (is_free_buddy_page(p)) {
Xie XiuQicc637b12015-06-24 16:57:30 -07001109 action_result(pfn, MF_MSG_BUDDY, MF_DELAYED);
Wu Fengguang8d22ba12009-12-16 12:19:58 +01001110 return 0;
Naoya Horiguchi8c6c2ec2010-09-08 10:19:38 +09001111 } else if (PageHuge(hpage)) {
1112 /*
Chen Yucongb9851942014-05-22 11:54:15 -07001113 * Check "filter hit" and "race with other subpage."
Naoya Horiguchi8c6c2ec2010-09-08 10:19:38 +09001114 */
Jens Axboe7eaceac2011-03-10 08:52:07 +01001115 lock_page(hpage);
Chen Yucongb9851942014-05-22 11:54:15 -07001116 if (PageHWPoison(hpage)) {
1117 if ((hwpoison_filter(p) && TestClearPageHWPoison(p))
1118 || (p != hpage && TestSetPageHWPoison(hpage))) {
1119 atomic_long_sub(nr_pages, &num_poisoned_pages);
1120 unlock_page(hpage);
1121 return 0;
1122 }
Naoya Horiguchi8c6c2ec2010-09-08 10:19:38 +09001123 }
1124 set_page_hwpoison_huge_page(hpage);
1125 res = dequeue_hwpoisoned_huge_page(hpage);
Xie XiuQicc637b12015-06-24 16:57:30 -07001126 action_result(pfn, MF_MSG_FREE_HUGE,
1127 res ? MF_IGNORED : MF_DELAYED);
Naoya Horiguchi8c6c2ec2010-09-08 10:19:38 +09001128 unlock_page(hpage);
1129 return res;
Wu Fengguang8d22ba12009-12-16 12:19:58 +01001130 } else {
Xie XiuQicc637b12015-06-24 16:57:30 -07001131 action_result(pfn, MF_MSG_KERNEL_HIGH_ORDER, MF_IGNORED);
Wu Fengguang8d22ba12009-12-16 12:19:58 +01001132 return -EBUSY;
1133 }
Andi Kleen6a460792009-09-16 11:50:15 +02001134 }
1135
Naoya Horiguchi415c64c2015-06-24 16:56:45 -07001136 if (!PageHuge(p) && PageTransHuge(hpage)) {
1137 if (!PageAnon(hpage)) {
1138 pr_err("MCE: %#lx: non anonymous thp\n", pfn);
Naoya Horiguchiead07f62015-06-24 16:56:48 -07001139 if (TestClearPageHWPoison(p))
1140 atomic_long_sub(nr_pages, &num_poisoned_pages);
Naoya Horiguchi415c64c2015-06-24 16:56:45 -07001141 put_page(p);
Naoya Horiguchiead07f62015-06-24 16:56:48 -07001142 if (p != hpage)
1143 put_page(hpage);
Naoya Horiguchi415c64c2015-06-24 16:56:45 -07001144 return -EBUSY;
1145 }
1146 if (unlikely(split_huge_page(hpage))) {
1147 pr_err("MCE: %#lx: thp split failed\n", pfn);
Naoya Horiguchiead07f62015-06-24 16:56:48 -07001148 if (TestClearPageHWPoison(p))
1149 atomic_long_sub(nr_pages, &num_poisoned_pages);
Naoya Horiguchi415c64c2015-06-24 16:56:45 -07001150 put_page(p);
Naoya Horiguchiead07f62015-06-24 16:56:48 -07001151 if (p != hpage)
1152 put_page(hpage);
Naoya Horiguchi415c64c2015-06-24 16:56:45 -07001153 return -EBUSY;
1154 }
1155 VM_BUG_ON_PAGE(!page_count(p), p);
1156 hpage = compound_head(p);
1157 }
1158
Andi Kleen6a460792009-09-16 11:50:15 +02001159 /*
Wu Fengguange43c3af2009-09-29 13:16:20 +08001160 * We ignore non-LRU pages for good reasons.
1161 * - PG_locked is only well defined for LRU pages and a few others
1162 * - to avoid races with __set_page_locked()
1163 * - to avoid races with __SetPageSlab*() (and more non-atomic ops)
1164 * The check (unnecessarily) ignores LRU pages being isolated and
1165 * walked by the page reclaim code, however that's not a big loss.
1166 */
Naoya Horiguchi09789e52015-05-05 16:23:35 -07001167 if (!PageHuge(p)) {
Naoya Horiguchi415c64c2015-06-24 16:56:45 -07001168 if (!PageLRU(p))
1169 shake_page(p, 0);
1170 if (!PageLRU(p)) {
Jin Dongmingaf241a02011-02-01 15:52:41 -08001171 /*
1172 * shake_page could have turned it free.
1173 */
1174 if (is_free_buddy_page(p)) {
Wanpeng Li2d421ac2013-09-30 13:45:23 -07001175 if (flags & MF_COUNT_INCREASED)
Xie XiuQicc637b12015-06-24 16:57:30 -07001176 action_result(pfn, MF_MSG_BUDDY, MF_DELAYED);
Wanpeng Li2d421ac2013-09-30 13:45:23 -07001177 else
Xie XiuQicc637b12015-06-24 16:57:30 -07001178 action_result(pfn, MF_MSG_BUDDY_2ND,
1179 MF_DELAYED);
Jin Dongmingaf241a02011-02-01 15:52:41 -08001180 return 0;
1181 }
Andi Kleen0474a602009-12-16 12:20:00 +01001182 }
Wu Fengguange43c3af2009-09-29 13:16:20 +08001183 }
Wu Fengguange43c3af2009-09-29 13:16:20 +08001184
Jens Axboe7eaceac2011-03-10 08:52:07 +01001185 lock_page(hpage);
Wu Fengguang847ce402009-12-16 12:19:58 +01001186
1187 /*
Andi Kleenf37d4292014-08-06 16:06:49 -07001188 * The page could have changed compound pages during the locking.
1189 * If this happens just bail out.
1190 */
Naoya Horiguchi415c64c2015-06-24 16:56:45 -07001191 if (PageCompound(p) && compound_head(p) != orig_head) {
Xie XiuQicc637b12015-06-24 16:57:30 -07001192 action_result(pfn, MF_MSG_DIFFERENT_COMPOUND, MF_IGNORED);
Andi Kleenf37d4292014-08-06 16:06:49 -07001193 res = -EBUSY;
1194 goto out;
1195 }
1196
1197 /*
Naoya Horiguchi524fca12013-02-22 16:35:51 -08001198 * We use page flags to determine what action should be taken, but
1199 * the flags can be modified by the error containment action. One
1200 * example is an mlocked page, where PG_mlocked is cleared by
1201 * page_remove_rmap() in try_to_unmap_one(). So to determine page status
1202 * correctly, we save a copy of the page flags at this time.
1203 */
1204 page_flags = p->flags;
1205
1206 /*
Wu Fengguang847ce402009-12-16 12:19:58 +01001207 * unpoison always clear PG_hwpoison inside page lock
1208 */
1209 if (!PageHWPoison(p)) {
Wu Fengguangd95ea512009-12-16 12:19:58 +01001210 printk(KERN_ERR "MCE %#lx: just unpoisoned\n", pfn);
Naoya Horiguchi3e030ec2014-05-22 11:54:21 -07001211 atomic_long_sub(nr_pages, &num_poisoned_pages);
1212 put_page(hpage);
Wu Fengguang847ce402009-12-16 12:19:58 +01001213 res = 0;
1214 goto out;
1215 }
Wu Fengguang7c116f22009-12-16 12:19:59 +01001216 if (hwpoison_filter(p)) {
1217 if (TestClearPageHWPoison(p))
Xishi Qiu293c07e2013-02-22 16:34:02 -08001218 atomic_long_sub(nr_pages, &num_poisoned_pages);
Naoya Horiguchi7af446a2010-05-28 09:29:17 +09001219 unlock_page(hpage);
1220 put_page(hpage);
Wu Fengguang7c116f22009-12-16 12:19:59 +01001221 return 0;
1222 }
Wu Fengguang847ce402009-12-16 12:19:58 +01001223
Chen Yucong0bc1f8b2014-07-02 15:22:37 -07001224 if (!PageHuge(p) && !PageTransTail(p) && !PageLRU(p))
1225 goto identify_page_state;
1226
Naoya Horiguchi7013feb2010-05-28 09:29:18 +09001227 /*
1228 * For error on the tail page, we should set PG_hwpoison
1229 * on the head page to show that the hugepage is hwpoisoned
1230 */
Jin Dongminga6d30dd2011-02-01 15:52:40 -08001231 if (PageHuge(p) && PageTail(p) && TestSetPageHWPoison(hpage)) {
Xie XiuQicc637b12015-06-24 16:57:30 -07001232 action_result(pfn, MF_MSG_POISONED_HUGE, MF_IGNORED);
Naoya Horiguchi7013feb2010-05-28 09:29:18 +09001233 unlock_page(hpage);
1234 put_page(hpage);
1235 return 0;
1236 }
1237 /*
1238 * Set PG_hwpoison on all pages in an error hugepage,
1239 * because containment is done in hugepage unit for now.
1240 * Since we have done TestSetPageHWPoison() for the head page with
1241 * page lock held, we can safely set PG_hwpoison bits on tail pages.
1242 */
1243 if (PageHuge(p))
1244 set_page_hwpoison_huge_page(hpage);
1245
Naoya Horiguchi6edd6cc2014-06-04 16:10:35 -07001246 /*
1247 * It's very difficult to mess with pages currently under IO
1248 * and in many cases impossible, so we just avoid it here.
1249 */
Andi Kleen6a460792009-09-16 11:50:15 +02001250 wait_on_page_writeback(p);
1251
1252 /*
1253 * Now take care of user space mappings.
Minchan Kime64a7822011-03-22 16:32:44 -07001254 * Abort on fail: __delete_from_page_cache() assumes unmapped page.
Naoya Horiguchi54b9dd12014-01-23 15:53:14 -08001255 *
1256 * When the raw error page is thp tail page, hpage points to the raw
1257 * page after thp split.
Andi Kleen6a460792009-09-16 11:50:15 +02001258 */
Naoya Horiguchi54b9dd12014-01-23 15:53:14 -08001259 if (hwpoison_user_mappings(p, pfn, trapno, flags, &hpage)
1260 != SWAP_SUCCESS) {
Xie XiuQicc637b12015-06-24 16:57:30 -07001261 action_result(pfn, MF_MSG_UNMAP_FAILED, MF_IGNORED);
Wu Fengguang1668bfd2009-12-16 12:19:58 +01001262 res = -EBUSY;
1263 goto out;
1264 }
Andi Kleen6a460792009-09-16 11:50:15 +02001265
1266 /*
1267 * Torn down by someone else?
1268 */
Wu Fengguangdc2a1cb2009-12-16 12:19:58 +01001269 if (PageLRU(p) && !PageSwapCache(p) && p->mapping == NULL) {
Xie XiuQicc637b12015-06-24 16:57:30 -07001270 action_result(pfn, MF_MSG_TRUNCATED_LRU, MF_IGNORED);
Wu Fengguangd95ea512009-12-16 12:19:58 +01001271 res = -EBUSY;
Andi Kleen6a460792009-09-16 11:50:15 +02001272 goto out;
1273 }
1274
Chen Yucong0bc1f8b2014-07-02 15:22:37 -07001275identify_page_state:
Andi Kleen6a460792009-09-16 11:50:15 +02001276 res = -EBUSY;
Naoya Horiguchi524fca12013-02-22 16:35:51 -08001277 /*
1278 * The first check uses the current page flags which may not have any
1279 * relevant information. The second check with the saved page flagss is
1280 * carried out only if the first check can't determine the page status.
1281 */
1282 for (ps = error_states;; ps++)
1283 if ((p->flags & ps->mask) == ps->res)
Andi Kleen6a460792009-09-16 11:50:15 +02001284 break;
Wanpeng Li841fcc52013-09-11 14:22:50 -07001285
1286 page_flags |= (p->flags & (1UL << PG_dirty));
1287
Naoya Horiguchi524fca12013-02-22 16:35:51 -08001288 if (!ps->mask)
1289 for (ps = error_states;; ps++)
1290 if ((page_flags & ps->mask) == ps->res)
1291 break;
1292 res = page_action(ps, p, pfn);
Andi Kleen6a460792009-09-16 11:50:15 +02001293out:
Naoya Horiguchi7af446a2010-05-28 09:29:17 +09001294 unlock_page(hpage);
Andi Kleen6a460792009-09-16 11:50:15 +02001295 return res;
1296}
Tony Luckcd42f4a2011-12-15 10:48:12 -08001297EXPORT_SYMBOL_GPL(memory_failure);
Wu Fengguang847ce402009-12-16 12:19:58 +01001298
Huang Yingea8f5fb2011-07-13 13:14:27 +08001299#define MEMORY_FAILURE_FIFO_ORDER 4
1300#define MEMORY_FAILURE_FIFO_SIZE (1 << MEMORY_FAILURE_FIFO_ORDER)
1301
1302struct memory_failure_entry {
1303 unsigned long pfn;
1304 int trapno;
1305 int flags;
1306};
1307
1308struct memory_failure_cpu {
1309 DECLARE_KFIFO(fifo, struct memory_failure_entry,
1310 MEMORY_FAILURE_FIFO_SIZE);
1311 spinlock_t lock;
1312 struct work_struct work;
1313};
1314
1315static DEFINE_PER_CPU(struct memory_failure_cpu, memory_failure_cpu);
1316
1317/**
1318 * memory_failure_queue - Schedule handling memory failure of a page.
1319 * @pfn: Page Number of the corrupted page
1320 * @trapno: Trap number reported in the signal to user space.
1321 * @flags: Flags for memory failure handling
1322 *
1323 * This function is called by the low level hardware error handler
1324 * when it detects hardware memory corruption of a page. It schedules
1325 * the recovering of error page, including dropping pages, killing
1326 * processes etc.
1327 *
1328 * The function is primarily of use for corruptions that
1329 * happen outside the current execution context (e.g. when
1330 * detected by a background scrubber)
1331 *
1332 * Can run in IRQ context.
1333 */
1334void memory_failure_queue(unsigned long pfn, int trapno, int flags)
1335{
1336 struct memory_failure_cpu *mf_cpu;
1337 unsigned long proc_flags;
1338 struct memory_failure_entry entry = {
1339 .pfn = pfn,
1340 .trapno = trapno,
1341 .flags = flags,
1342 };
1343
1344 mf_cpu = &get_cpu_var(memory_failure_cpu);
1345 spin_lock_irqsave(&mf_cpu->lock, proc_flags);
Stefani Seibold498d3192013-11-14 14:32:17 -08001346 if (kfifo_put(&mf_cpu->fifo, entry))
Huang Yingea8f5fb2011-07-13 13:14:27 +08001347 schedule_work_on(smp_processor_id(), &mf_cpu->work);
1348 else
Joe Perches8e33a522013-07-25 11:53:25 -07001349 pr_err("Memory failure: buffer overflow when queuing memory failure at %#lx\n",
Huang Yingea8f5fb2011-07-13 13:14:27 +08001350 pfn);
1351 spin_unlock_irqrestore(&mf_cpu->lock, proc_flags);
1352 put_cpu_var(memory_failure_cpu);
1353}
1354EXPORT_SYMBOL_GPL(memory_failure_queue);
1355
1356static void memory_failure_work_func(struct work_struct *work)
1357{
1358 struct memory_failure_cpu *mf_cpu;
1359 struct memory_failure_entry entry = { 0, };
1360 unsigned long proc_flags;
1361 int gotten;
1362
Christoph Lameter7c8e0182014-06-04 16:07:56 -07001363 mf_cpu = this_cpu_ptr(&memory_failure_cpu);
Huang Yingea8f5fb2011-07-13 13:14:27 +08001364 for (;;) {
1365 spin_lock_irqsave(&mf_cpu->lock, proc_flags);
1366 gotten = kfifo_get(&mf_cpu->fifo, &entry);
1367 spin_unlock_irqrestore(&mf_cpu->lock, proc_flags);
1368 if (!gotten)
1369 break;
Naveen N. Raocf870c72013-07-10 14:57:01 +05301370 if (entry.flags & MF_SOFT_OFFLINE)
1371 soft_offline_page(pfn_to_page(entry.pfn), entry.flags);
1372 else
1373 memory_failure(entry.pfn, entry.trapno, entry.flags);
Huang Yingea8f5fb2011-07-13 13:14:27 +08001374 }
1375}
1376
1377static int __init memory_failure_init(void)
1378{
1379 struct memory_failure_cpu *mf_cpu;
1380 int cpu;
1381
1382 for_each_possible_cpu(cpu) {
1383 mf_cpu = &per_cpu(memory_failure_cpu, cpu);
1384 spin_lock_init(&mf_cpu->lock);
1385 INIT_KFIFO(mf_cpu->fifo);
1386 INIT_WORK(&mf_cpu->work, memory_failure_work_func);
1387 }
1388
1389 return 0;
1390}
1391core_initcall(memory_failure_init);
1392
Wu Fengguang847ce402009-12-16 12:19:58 +01001393/**
1394 * unpoison_memory - Unpoison a previously poisoned page
1395 * @pfn: Page number of the to be unpoisoned page
1396 *
1397 * Software-unpoison a page that has been poisoned by
1398 * memory_failure() earlier.
1399 *
1400 * This is only done on the software-level, so it only works
1401 * for linux injected failures, not real hardware failures
1402 *
1403 * Returns 0 for success, otherwise -errno.
1404 */
1405int unpoison_memory(unsigned long pfn)
1406{
1407 struct page *page;
1408 struct page *p;
1409 int freeit = 0;
Naoya Horiguchic9fbdd52010-05-28 09:29:19 +09001410 unsigned int nr_pages;
Wu Fengguang847ce402009-12-16 12:19:58 +01001411
1412 if (!pfn_valid(pfn))
1413 return -ENXIO;
1414
1415 p = pfn_to_page(pfn);
1416 page = compound_head(p);
1417
1418 if (!PageHWPoison(p)) {
Andi Kleenfb46e732010-09-27 23:31:30 +02001419 pr_info("MCE: Page was already unpoisoned %#lx\n", pfn);
Wu Fengguang847ce402009-12-16 12:19:58 +01001420 return 0;
1421 }
1422
Wanpeng Li0cea3fd2013-09-11 14:22:53 -07001423 /*
1424 * unpoison_memory() can encounter thp only when the thp is being
1425 * worked by memory_failure() and the page lock is not held yet.
1426 * In such case, we yield to memory_failure() and make unpoison fail.
1427 */
Wanpeng Lie76d30e2013-09-30 13:45:22 -07001428 if (!PageHuge(page) && PageTransHuge(page)) {
Wanpeng Li0cea3fd2013-09-11 14:22:53 -07001429 pr_info("MCE: Memory failure is now running on %#lx\n", pfn);
Naoya Horiguchiead07f62015-06-24 16:56:48 -07001430 return 0;
Wanpeng Li0cea3fd2013-09-11 14:22:53 -07001431 }
1432
Wanpeng Lif9121152013-09-11 14:22:52 -07001433 nr_pages = 1 << compound_order(page);
Naoya Horiguchic9fbdd52010-05-28 09:29:19 +09001434
Naoya Horiguchiead07f62015-06-24 16:56:48 -07001435 if (!get_hwpoison_page(p)) {
Naoya Horiguchi8c6c2ec2010-09-08 10:19:38 +09001436 /*
1437 * Since HWPoisoned hugepage should have non-zero refcount,
1438 * race between memory failure and unpoison seems to happen.
1439 * In such case unpoison fails and memory failure runs
1440 * to the end.
1441 */
1442 if (PageHuge(page)) {
Dean Nelsondd73e852011-10-31 17:09:04 -07001443 pr_info("MCE: Memory failure is now running on free hugepage %#lx\n", pfn);
Naoya Horiguchi8c6c2ec2010-09-08 10:19:38 +09001444 return 0;
1445 }
Wu Fengguang847ce402009-12-16 12:19:58 +01001446 if (TestClearPageHWPoison(p))
Wanpeng Lidd9538a2013-09-11 14:22:54 -07001447 atomic_long_dec(&num_poisoned_pages);
Andi Kleenfb46e732010-09-27 23:31:30 +02001448 pr_info("MCE: Software-unpoisoned free page %#lx\n", pfn);
Wu Fengguang847ce402009-12-16 12:19:58 +01001449 return 0;
1450 }
1451
Jens Axboe7eaceac2011-03-10 08:52:07 +01001452 lock_page(page);
Wu Fengguang847ce402009-12-16 12:19:58 +01001453 /*
1454 * This test is racy because PG_hwpoison is set outside of page lock.
1455 * That's acceptable because that won't trigger kernel panic. Instead,
1456 * the PG_hwpoison page will be caught and isolated on the entrance to
1457 * the free buddy page pool.
1458 */
Naoya Horiguchic9fbdd52010-05-28 09:29:19 +09001459 if (TestClearPageHWPoison(page)) {
Andi Kleenfb46e732010-09-27 23:31:30 +02001460 pr_info("MCE: Software-unpoisoned page %#lx\n", pfn);
Xishi Qiu293c07e2013-02-22 16:34:02 -08001461 atomic_long_sub(nr_pages, &num_poisoned_pages);
Wu Fengguang847ce402009-12-16 12:19:58 +01001462 freeit = 1;
Naoya Horiguchi6a901812010-09-08 10:19:40 +09001463 if (PageHuge(page))
1464 clear_page_hwpoison_huge_page(page);
Wu Fengguang847ce402009-12-16 12:19:58 +01001465 }
1466 unlock_page(page);
1467
1468 put_page(page);
Wanpeng Li3ba5eeb2013-09-11 14:23:01 -07001469 if (freeit && !(pfn == my_zero_pfn(0) && page_count(p) == 1))
Wu Fengguang847ce402009-12-16 12:19:58 +01001470 put_page(page);
1471
1472 return 0;
1473}
1474EXPORT_SYMBOL(unpoison_memory);
Andi Kleenfacb6012009-12-16 12:20:00 +01001475
1476static struct page *new_page(struct page *p, unsigned long private, int **x)
1477{
Andi Kleen12686d12009-12-16 12:20:01 +01001478 int nid = page_to_nid(p);
Naoya Horiguchid950b952010-09-08 10:19:39 +09001479 if (PageHuge(p))
1480 return alloc_huge_page_node(page_hstate(compound_head(p)),
1481 nid);
1482 else
1483 return alloc_pages_exact_node(nid, GFP_HIGHUSER_MOVABLE, 0);
Andi Kleenfacb6012009-12-16 12:20:00 +01001484}
1485
1486/*
1487 * Safely get reference count of an arbitrary page.
1488 * Returns 0 for a free page, -EIO for a zero refcount page
1489 * that is not free, and 1 for any other page type.
1490 * For 1 the page is returned with increased page count, otherwise not.
1491 */
Naoya Horiguchiaf8fae72013-02-22 16:34:03 -08001492static int __get_any_page(struct page *p, unsigned long pfn, int flags)
Andi Kleenfacb6012009-12-16 12:20:00 +01001493{
1494 int ret;
1495
1496 if (flags & MF_COUNT_INCREASED)
1497 return 1;
1498
1499 /*
Naoya Horiguchid950b952010-09-08 10:19:39 +09001500 * When the target page is a free hugepage, just remove it
1501 * from free hugepage list.
1502 */
Naoya Horiguchiead07f62015-06-24 16:56:48 -07001503 if (!get_hwpoison_page(p)) {
Naoya Horiguchid950b952010-09-08 10:19:39 +09001504 if (PageHuge(p)) {
Borislav Petkov71dd0b82012-05-29 15:06:16 -07001505 pr_info("%s: %#lx free huge page\n", __func__, pfn);
Naoya Horiguchiaf8fae72013-02-22 16:34:03 -08001506 ret = 0;
Naoya Horiguchid950b952010-09-08 10:19:39 +09001507 } else if (is_free_buddy_page(p)) {
Borislav Petkov71dd0b82012-05-29 15:06:16 -07001508 pr_info("%s: %#lx free buddy page\n", __func__, pfn);
Andi Kleenfacb6012009-12-16 12:20:00 +01001509 ret = 0;
1510 } else {
Borislav Petkov71dd0b82012-05-29 15:06:16 -07001511 pr_info("%s: %#lx: unknown zero refcount page type %lx\n",
1512 __func__, pfn, p->flags);
Andi Kleenfacb6012009-12-16 12:20:00 +01001513 ret = -EIO;
1514 }
1515 } else {
1516 /* Not a free page */
1517 ret = 1;
1518 }
Andi Kleenfacb6012009-12-16 12:20:00 +01001519 return ret;
1520}
1521
Naoya Horiguchiaf8fae72013-02-22 16:34:03 -08001522static int get_any_page(struct page *page, unsigned long pfn, int flags)
1523{
1524 int ret = __get_any_page(page, pfn, flags);
1525
1526 if (ret == 1 && !PageHuge(page) && !PageLRU(page)) {
1527 /*
1528 * Try to free it.
1529 */
1530 put_page(page);
1531 shake_page(page, 1);
1532
1533 /*
1534 * Did it turn free?
1535 */
1536 ret = __get_any_page(page, pfn, 0);
1537 if (!PageLRU(page)) {
1538 pr_info("soft_offline: %#lx: unknown non LRU page type %lx\n",
1539 pfn, page->flags);
1540 return -EIO;
1541 }
1542 }
1543 return ret;
1544}
1545
Naoya Horiguchid950b952010-09-08 10:19:39 +09001546static int soft_offline_huge_page(struct page *page, int flags)
1547{
1548 int ret;
1549 unsigned long pfn = page_to_pfn(page);
1550 struct page *hpage = compound_head(page);
Naoya Horiguchib8ec1ce2013-09-11 14:22:01 -07001551 LIST_HEAD(pagelist);
Naoya Horiguchid950b952010-09-08 10:19:39 +09001552
Naoya Horiguchiaf8fae72013-02-22 16:34:03 -08001553 /*
1554 * This double-check of PageHWPoison is to avoid the race with
1555 * memory_failure(). See also comment in __soft_offline_page().
1556 */
1557 lock_page(hpage);
Xishi Qiu0ebff322013-02-22 16:33:59 -08001558 if (PageHWPoison(hpage)) {
Naoya Horiguchiaf8fae72013-02-22 16:34:03 -08001559 unlock_page(hpage);
1560 put_page(hpage);
Xishi Qiu0ebff322013-02-22 16:33:59 -08001561 pr_info("soft offline: %#lx hugepage already poisoned\n", pfn);
Naoya Horiguchiaf8fae72013-02-22 16:34:03 -08001562 return -EBUSY;
Xishi Qiu0ebff322013-02-22 16:33:59 -08001563 }
Naoya Horiguchiaf8fae72013-02-22 16:34:03 -08001564 unlock_page(hpage);
Naoya Horiguchid950b952010-09-08 10:19:39 +09001565
Naoya Horiguchibcc54222015-04-15 16:14:38 -07001566 ret = isolate_huge_page(hpage, &pagelist);
1567 if (ret) {
1568 /*
1569 * get_any_page() and isolate_huge_page() takes a refcount each,
1570 * so need to drop one here.
1571 */
1572 put_page(hpage);
1573 } else {
1574 pr_info("soft offline: %#lx hugepage failed to isolate\n", pfn);
1575 return -EBUSY;
1576 }
1577
David Rientjes68711a72014-06-04 16:08:25 -07001578 ret = migrate_pages(&pagelist, new_page, NULL, MPOL_MF_MOVE_ALL,
Naoya Horiguchib8ec1ce2013-09-11 14:22:01 -07001579 MIGRATE_SYNC, MR_MEMORY_FAILURE);
Naoya Horiguchid950b952010-09-08 10:19:39 +09001580 if (ret) {
Dean Nelsondd73e852011-10-31 17:09:04 -07001581 pr_info("soft offline: %#lx: migration failed %d, type %lx\n",
1582 pfn, ret, page->flags);
Naoya Horiguchib8ec1ce2013-09-11 14:22:01 -07001583 /*
1584 * We know that soft_offline_huge_page() tries to migrate
1585 * only one hugepage pointed to by hpage, so we need not
1586 * run through the pagelist here.
1587 */
1588 putback_active_hugepage(hpage);
1589 if (ret > 0)
1590 ret = -EIO;
Naoya Horiguchiaf8fae72013-02-22 16:34:03 -08001591 } else {
Jianguo Wua49ecbc2013-12-18 17:08:54 -08001592 /* overcommit hugetlb page will be freed to buddy */
1593 if (PageHuge(page)) {
1594 set_page_hwpoison_huge_page(hpage);
1595 dequeue_hwpoisoned_huge_page(hpage);
1596 atomic_long_add(1 << compound_order(hpage),
1597 &num_poisoned_pages);
1598 } else {
1599 SetPageHWPoison(page);
1600 atomic_long_inc(&num_poisoned_pages);
1601 }
Naoya Horiguchid950b952010-09-08 10:19:39 +09001602 }
Naoya Horiguchid950b952010-09-08 10:19:39 +09001603 return ret;
1604}
1605
Naoya Horiguchiaf8fae72013-02-22 16:34:03 -08001606static int __soft_offline_page(struct page *page, int flags)
1607{
1608 int ret;
1609 unsigned long pfn = page_to_pfn(page);
Andi Kleenfacb6012009-12-16 12:20:00 +01001610
1611 /*
Naoya Horiguchiaf8fae72013-02-22 16:34:03 -08001612 * Check PageHWPoison again inside page lock because PageHWPoison
1613 * is set by memory_failure() outside page lock. Note that
1614 * memory_failure() also double-checks PageHWPoison inside page lock,
1615 * so there's no race between soft_offline_page() and memory_failure().
Andi Kleenfacb6012009-12-16 12:20:00 +01001616 */
Xishi Qiu0ebff322013-02-22 16:33:59 -08001617 lock_page(page);
1618 wait_on_page_writeback(page);
Naoya Horiguchiaf8fae72013-02-22 16:34:03 -08001619 if (PageHWPoison(page)) {
1620 unlock_page(page);
1621 put_page(page);
1622 pr_info("soft offline: %#lx page already poisoned\n", pfn);
1623 return -EBUSY;
1624 }
Andi Kleenfacb6012009-12-16 12:20:00 +01001625 /*
1626 * Try to invalidate first. This should work for
1627 * non dirty unmapped page cache pages.
1628 */
1629 ret = invalidate_inode_page(page);
1630 unlock_page(page);
Andi Kleenfacb6012009-12-16 12:20:00 +01001631 /*
Andi Kleenfacb6012009-12-16 12:20:00 +01001632 * RED-PEN would be better to keep it isolated here, but we
1633 * would need to fix isolation locking first.
1634 */
Andi Kleenfacb6012009-12-16 12:20:00 +01001635 if (ret == 1) {
Konstantin Khlebnikovbd486282011-05-24 17:12:20 -07001636 put_page(page);
Andi Kleenfb46e732010-09-27 23:31:30 +02001637 pr_info("soft_offline: %#lx: invalidated\n", pfn);
Naoya Horiguchiaf8fae72013-02-22 16:34:03 -08001638 SetPageHWPoison(page);
1639 atomic_long_inc(&num_poisoned_pages);
1640 return 0;
Andi Kleenfacb6012009-12-16 12:20:00 +01001641 }
1642
1643 /*
1644 * Simple invalidation didn't work.
1645 * Try to migrate to a new page instead. migrate.c
1646 * handles a large number of cases for us.
1647 */
1648 ret = isolate_lru_page(page);
Konstantin Khlebnikovbd486282011-05-24 17:12:20 -07001649 /*
1650 * Drop page reference which is came from get_any_page()
1651 * successful isolate_lru_page() already took another one.
1652 */
1653 put_page(page);
Andi Kleenfacb6012009-12-16 12:20:00 +01001654 if (!ret) {
1655 LIST_HEAD(pagelist);
Minchan Kim5db8a732011-06-15 15:08:48 -07001656 inc_zone_page_state(page, NR_ISOLATED_ANON +
Hugh Dickins9c620e22013-02-22 16:35:14 -08001657 page_is_file_cache(page));
Andi Kleenfacb6012009-12-16 12:20:00 +01001658 list_add(&page->lru, &pagelist);
David Rientjes68711a72014-06-04 16:08:25 -07001659 ret = migrate_pages(&pagelist, new_page, NULL, MPOL_MF_MOVE_ALL,
Hugh Dickins9c620e22013-02-22 16:35:14 -08001660 MIGRATE_SYNC, MR_MEMORY_FAILURE);
Andi Kleenfacb6012009-12-16 12:20:00 +01001661 if (ret) {
Joonsoo Kim59c82b72014-01-21 15:51:17 -08001662 if (!list_empty(&pagelist)) {
1663 list_del(&page->lru);
1664 dec_zone_page_state(page, NR_ISOLATED_ANON +
1665 page_is_file_cache(page));
1666 putback_lru_page(page);
1667 }
1668
Andi Kleenfb46e732010-09-27 23:31:30 +02001669 pr_info("soft offline: %#lx: migration failed %d, type %lx\n",
Andi Kleenfacb6012009-12-16 12:20:00 +01001670 pfn, ret, page->flags);
1671 if (ret > 0)
1672 ret = -EIO;
Naoya Horiguchiaf8fae72013-02-22 16:34:03 -08001673 } else {
1674 SetPageHWPoison(page);
1675 atomic_long_inc(&num_poisoned_pages);
Andi Kleenfacb6012009-12-16 12:20:00 +01001676 }
1677 } else {
Andi Kleenfb46e732010-09-27 23:31:30 +02001678 pr_info("soft offline: %#lx: isolation failed: %d, page count %d, type %lx\n",
Dean Nelsondd73e852011-10-31 17:09:04 -07001679 pfn, ret, page_count(page), page->flags);
Andi Kleenfacb6012009-12-16 12:20:00 +01001680 }
Andi Kleenfacb6012009-12-16 12:20:00 +01001681 return ret;
1682}
Wanpeng Li86e05772013-09-11 14:22:56 -07001683
1684/**
1685 * soft_offline_page - Soft offline a page.
1686 * @page: page to offline
1687 * @flags: flags. Same as memory_failure().
1688 *
1689 * Returns 0 on success, otherwise negated errno.
1690 *
1691 * Soft offline a page, by migration or invalidation,
1692 * without killing anything. This is for the case when
1693 * a page is not corrupted yet (so it's still valid to access),
1694 * but has had a number of corrected errors and is better taken
1695 * out.
1696 *
1697 * The actual policy on when to do that is maintained by
1698 * user space.
1699 *
1700 * This should never impact any application or cause data loss,
1701 * however it might take some time.
1702 *
1703 * This is not a 100% solution for all memory, but tries to be
1704 * ``good enough'' for the majority of memory.
1705 */
1706int soft_offline_page(struct page *page, int flags)
1707{
1708 int ret;
1709 unsigned long pfn = page_to_pfn(page);
David Rientjes668f9abb2014-03-03 15:38:18 -08001710 struct page *hpage = compound_head(page);
Wanpeng Li86e05772013-09-11 14:22:56 -07001711
1712 if (PageHWPoison(page)) {
1713 pr_info("soft offline: %#lx page already poisoned\n", pfn);
1714 return -EBUSY;
1715 }
1716 if (!PageHuge(page) && PageTransHuge(hpage)) {
1717 if (PageAnon(hpage) && unlikely(split_huge_page(hpage))) {
1718 pr_info("soft offline: %#lx: failed to split THP\n",
1719 pfn);
1720 return -EBUSY;
1721 }
1722 }
1723
Vladimir Davydovbfc8c902014-06-04 16:07:18 -07001724 get_online_mems();
Naoya Horiguchi03b61ff2013-11-12 15:07:26 -08001725
Wanpeng Li86e05772013-09-11 14:22:56 -07001726 ret = get_any_page(page, pfn, flags);
Vladimir Davydovbfc8c902014-06-04 16:07:18 -07001727 put_online_mems();
Naoya Horiguchi03b61ff2013-11-12 15:07:26 -08001728 if (ret > 0) { /* for in-use pages */
Wanpeng Li86e05772013-09-11 14:22:56 -07001729 if (PageHuge(page))
1730 ret = soft_offline_huge_page(page, flags);
1731 else
1732 ret = __soft_offline_page(page, flags);
Naoya Horiguchi03b61ff2013-11-12 15:07:26 -08001733 } else if (ret == 0) { /* for free pages */
Wanpeng Li86e05772013-09-11 14:22:56 -07001734 if (PageHuge(page)) {
1735 set_page_hwpoison_huge_page(hpage);
Naoya Horiguchi602498f2015-05-05 16:23:46 -07001736 if (!dequeue_hwpoisoned_huge_page(hpage))
1737 atomic_long_add(1 << compound_order(hpage),
Wanpeng Li86e05772013-09-11 14:22:56 -07001738 &num_poisoned_pages);
1739 } else {
Naoya Horiguchi602498f2015-05-05 16:23:46 -07001740 if (!TestSetPageHWPoison(page))
1741 atomic_long_inc(&num_poisoned_pages);
Wanpeng Li86e05772013-09-11 14:22:56 -07001742 }
1743 }
Wanpeng Li86e05772013-09-11 14:22:56 -07001744 return ret;
1745}