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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.
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.
Andi Kleen6a460792009-09-16 11:50:15 +020030 */
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 */
Andi Kleen6a460792009-09-16 11:50:15 +020038#include <linux/kernel.h>
39#include <linux/mm.h>
40#include <linux/page-flags.h>
Wu Fengguang478c5ff2009-12-16 12:19:59 +010041#include <linux/kernel-page-flags.h>
Andi Kleen6a460792009-09-16 11:50:15 +020042#include <linux/sched.h>
Hugh Dickins01e00f82009-10-13 15:02:11 +010043#include <linux/ksm.h>
Andi Kleen6a460792009-09-16 11:50:15 +020044#include <linux/rmap.h>
Paul Gortmakerb9e15ba2011-05-26 16:00:52 -040045#include <linux/export.h>
Andi Kleen6a460792009-09-16 11:50:15 +020046#include <linux/pagemap.h>
47#include <linux/swap.h>
48#include <linux/backing-dev.h>
Andi Kleenfacb6012009-12-16 12:20:00 +010049#include <linux/migrate.h>
50#include <linux/page-isolation.h>
51#include <linux/suspend.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090052#include <linux/slab.h>
Huang Yingbf998152010-05-31 14:28:19 +080053#include <linux/swapops.h>
Naoya Horiguchi7af446a2010-05-28 09:29:17 +090054#include <linux/hugetlb.h>
KOSAKI Motohiro20d6c962010-12-02 14:31:19 -080055#include <linux/memory_hotplug.h>
Minchan Kim5db8a732011-06-15 15:08:48 -070056#include <linux/mm_inline.h>
Huang Yingea8f5fb2011-07-13 13:14:27 +080057#include <linux/kfifo.h>
Andi Kleen6a460792009-09-16 11:50:15 +020058#include "internal.h"
59
60int sysctl_memory_failure_early_kill __read_mostly = 0;
61
62int sysctl_memory_failure_recovery __read_mostly = 1;
63
64atomic_long_t mce_bad_pages __read_mostly = ATOMIC_LONG_INIT(0);
65
Andi Kleen27df5062009-12-21 19:56:42 +010066#if defined(CONFIG_HWPOISON_INJECT) || defined(CONFIG_HWPOISON_INJECT_MODULE)
67
Haicheng Li1bfe5fe2009-12-16 12:19:59 +010068u32 hwpoison_filter_enable = 0;
Wu Fengguang7c116f22009-12-16 12:19:59 +010069u32 hwpoison_filter_dev_major = ~0U;
70u32 hwpoison_filter_dev_minor = ~0U;
Wu Fengguang478c5ff2009-12-16 12:19:59 +010071u64 hwpoison_filter_flags_mask;
72u64 hwpoison_filter_flags_value;
Haicheng Li1bfe5fe2009-12-16 12:19:59 +010073EXPORT_SYMBOL_GPL(hwpoison_filter_enable);
Wu Fengguang7c116f22009-12-16 12:19:59 +010074EXPORT_SYMBOL_GPL(hwpoison_filter_dev_major);
75EXPORT_SYMBOL_GPL(hwpoison_filter_dev_minor);
Wu Fengguang478c5ff2009-12-16 12:19:59 +010076EXPORT_SYMBOL_GPL(hwpoison_filter_flags_mask);
77EXPORT_SYMBOL_GPL(hwpoison_filter_flags_value);
Wu Fengguang7c116f22009-12-16 12:19:59 +010078
79static 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 /*
Andi Kleen1c80b992010-09-27 23:09:51 +020089 * page_mapping() does not accept slab pages.
Wu Fengguang7c116f22009-12-16 12:19:59 +010090 */
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
Wu Fengguang478c5ff2009-12-16 12:19:59 +0100109static 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
Andi Kleen4fd466e2009-12-16 12:19:59 +0100121/*
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 */
131#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
132u64 hwpoison_filter_memcg;
133EXPORT_SYMBOL_GPL(hwpoison_filter_memcg);
134static 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);
148 /* root_mem_cgroup has NULL dentries */
149 if (!css->cgroup->dentry)
150 return -EINVAL;
151
152 ino = css->cgroup->dentry->d_inode->i_ino;
153 css_put(css);
154
155 if (ino != hwpoison_filter_memcg)
156 return -EINVAL;
157
158 return 0;
159}
160#else
161static int hwpoison_filter_task(struct page *p) { return 0; }
162#endif
163
Wu Fengguang7c116f22009-12-16 12:19:59 +0100164int hwpoison_filter(struct page *p)
165{
Haicheng Li1bfe5fe2009-12-16 12:19:59 +0100166 if (!hwpoison_filter_enable)
167 return 0;
168
Wu Fengguang7c116f22009-12-16 12:19:59 +0100169 if (hwpoison_filter_dev(p))
170 return -EINVAL;
171
Wu Fengguang478c5ff2009-12-16 12:19:59 +0100172 if (hwpoison_filter_flags(p))
173 return -EINVAL;
174
Andi Kleen4fd466e2009-12-16 12:19:59 +0100175 if (hwpoison_filter_task(p))
176 return -EINVAL;
177
Wu Fengguang7c116f22009-12-16 12:19:59 +0100178 return 0;
179}
Andi Kleen27df5062009-12-21 19:56:42 +0100180#else
181int hwpoison_filter(struct page *p)
182{
183 return 0;
184}
185#endif
186
Wu Fengguang7c116f22009-12-16 12:19:59 +0100187EXPORT_SYMBOL_GPL(hwpoison_filter);
188
Andi Kleen6a460792009-09-16 11:50:15 +0200189/*
190 * Send all the processes who have the page mapped an ``action optional''
191 * signal.
192 */
193static int kill_proc_ao(struct task_struct *t, unsigned long addr, int trapno,
Andi Kleen0d9ee6a2010-09-27 22:03:33 +0200194 unsigned long pfn, struct page *page)
Andi Kleen6a460792009-09-16 11:50:15 +0200195{
196 struct siginfo si;
197 int ret;
198
199 printk(KERN_ERR
200 "MCE %#lx: Killing %s:%d early due to hardware memory corruption\n",
201 pfn, t->comm, t->pid);
202 si.si_signo = SIGBUS;
203 si.si_errno = 0;
204 si.si_code = BUS_MCEERR_AO;
205 si.si_addr = (void *)addr;
206#ifdef __ARCH_SI_TRAPNO
207 si.si_trapno = trapno;
208#endif
Andrea Arcangeli37c2ac72011-01-13 15:47:16 -0800209 si.si_addr_lsb = compound_trans_order(compound_head(page)) + PAGE_SHIFT;
Andi Kleen6a460792009-09-16 11:50:15 +0200210 /*
211 * Don't use force here, it's convenient if the signal
212 * can be temporarily blocked.
213 * This could cause a loop when the user sets SIGBUS
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300214 * to SIG_IGN, but hopefully no one will do that?
Andi Kleen6a460792009-09-16 11:50:15 +0200215 */
216 ret = send_sig_info(SIGBUS, &si, t); /* synchronous? */
217 if (ret < 0)
218 printk(KERN_INFO "MCE: Error sending signal to %s:%d: %d\n",
219 t->comm, t->pid, ret);
220 return ret;
221}
222
223/*
Andi Kleen588f9ce2009-12-16 12:19:57 +0100224 * When a unknown page type is encountered drain as many buffers as possible
225 * in the hope to turn the page into a LRU or free page, which we can handle.
226 */
Andi Kleenfacb6012009-12-16 12:20:00 +0100227void shake_page(struct page *p, int access)
Andi Kleen588f9ce2009-12-16 12:19:57 +0100228{
229 if (!PageSlab(p)) {
230 lru_add_drain_all();
231 if (PageLRU(p))
232 return;
233 drain_all_pages();
234 if (PageLRU(p) || is_free_buddy_page(p))
235 return;
236 }
Andi Kleenfacb6012009-12-16 12:20:00 +0100237
Andi Kleen588f9ce2009-12-16 12:19:57 +0100238 /*
Jin Dongmingaf241a02011-02-01 15:52:41 -0800239 * Only call shrink_slab here (which would also shrink other caches) if
240 * access is not potentially fatal.
Andi Kleen588f9ce2009-12-16 12:19:57 +0100241 */
Andi Kleenfacb6012009-12-16 12:20:00 +0100242 if (access) {
243 int nr;
244 do {
Ying Hana09ed5e2011-05-24 17:12:26 -0700245 struct shrink_control shrink = {
246 .gfp_mask = GFP_KERNEL,
Ying Hana09ed5e2011-05-24 17:12:26 -0700247 };
248
Ying Han1495f232011-05-24 17:12:27 -0700249 nr = shrink_slab(&shrink, 1000, 1000);
Andi Kleen47f43e72010-09-28 07:37:55 +0200250 if (page_count(p) == 1)
Andi Kleenfacb6012009-12-16 12:20:00 +0100251 break;
252 } while (nr > 10);
253 }
Andi Kleen588f9ce2009-12-16 12:19:57 +0100254}
255EXPORT_SYMBOL_GPL(shake_page);
256
257/*
Andi Kleen6a460792009-09-16 11:50:15 +0200258 * 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
279struct to_kill {
280 struct list_head nd;
281 struct task_struct *tsk;
282 unsigned long addr;
Andi Kleen9033ae12010-09-27 23:36:05 +0200283 char addr_valid;
Andi Kleen6a460792009-09-16 11:50:15 +0200284};
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 */
296static 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) {
Andi Kleenfb46e732010-09-27 23:31:30 +0200324 pr_info("MCE: Unable to find user space address %lx in %s\n",
Andi Kleen6a460792009-09-16 11:50:15 +0200325 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 */
341static void kill_procs_ao(struct list_head *to_kill, int doit, int trapno,
Andi Kleen0d9ee6a2010-09-27 22:03:33 +0200342 int fail, struct page *page, unsigned long pfn)
Andi Kleen6a460792009-09-16 11:50:15 +0200343{
344 struct to_kill *tk, *next;
345
346 list_for_each_entry_safe (tk, next, to_kill, nd) {
347 if (doit) {
348 /*
André Goddard Rosaaf901ca2009-11-14 13:09:05 -0200349 * In case something went wrong with munmapping
Andi Kleen6a460792009-09-16 11:50:15 +0200350 * make sure the process doesn't catch the
351 * signal and then access the memory. Just kill it.
Andi Kleen6a460792009-09-16 11:50:15 +0200352 */
353 if (fail || tk->addr_valid == 0) {
354 printk(KERN_ERR
355 "MCE %#lx: forcibly killing %s:%d because of failure to unmap corrupted page\n",
356 pfn, tk->tsk->comm, tk->tsk->pid);
357 force_sig(SIGKILL, tk->tsk);
358 }
359
360 /*
361 * In theory the process could have mapped
362 * something else on the address in-between. We could
363 * check for that, but we need to tell the
364 * process anyways.
365 */
366 else if (kill_proc_ao(tk->tsk, tk->addr, trapno,
Andi Kleen0d9ee6a2010-09-27 22:03:33 +0200367 pfn, page) < 0)
Andi Kleen6a460792009-09-16 11:50:15 +0200368 printk(KERN_ERR
369 "MCE %#lx: Cannot send advisory machine check signal to %s:%d\n",
370 pfn, tk->tsk->comm, tk->tsk->pid);
371 }
372 put_task_struct(tk->tsk);
373 kfree(tk);
374 }
375}
376
377static int task_early_kill(struct task_struct *tsk)
378{
379 if (!tsk->mm)
380 return 0;
381 if (tsk->flags & PF_MCE_PROCESS)
382 return !!(tsk->flags & PF_MCE_EARLY);
383 return sysctl_memory_failure_early_kill;
384}
385
386/*
387 * Collect processes when the error hit an anonymous page.
388 */
389static void collect_procs_anon(struct page *page, struct list_head *to_kill,
390 struct to_kill **tkc)
391{
392 struct vm_area_struct *vma;
393 struct task_struct *tsk;
394 struct anon_vma *av;
395
Andi Kleen6a460792009-09-16 11:50:15 +0200396 av = page_lock_anon_vma(page);
397 if (av == NULL) /* Not actually mapped anymore */
Peter Zijlstra9b679322011-06-27 16:18:09 -0700398 return;
399
400 read_lock(&tasklist_lock);
Andi Kleen6a460792009-09-16 11:50:15 +0200401 for_each_process (tsk) {
Rik van Riel5beb4932010-03-05 13:42:07 -0800402 struct anon_vma_chain *vmac;
403
Andi Kleen6a460792009-09-16 11:50:15 +0200404 if (!task_early_kill(tsk))
405 continue;
Rik van Riel5beb4932010-03-05 13:42:07 -0800406 list_for_each_entry(vmac, &av->head, same_anon_vma) {
407 vma = vmac->vma;
Andi Kleen6a460792009-09-16 11:50:15 +0200408 if (!page_mapped_in_vma(page, vma))
409 continue;
410 if (vma->vm_mm == tsk->mm)
411 add_to_kill(tsk, page, vma, to_kill, tkc);
412 }
413 }
Andi Kleen6a460792009-09-16 11:50:15 +0200414 read_unlock(&tasklist_lock);
Peter Zijlstra9b679322011-06-27 16:18:09 -0700415 page_unlock_anon_vma(av);
Andi Kleen6a460792009-09-16 11:50:15 +0200416}
417
418/*
419 * Collect processes when the error hit a file mapped page.
420 */
421static void collect_procs_file(struct page *page, struct list_head *to_kill,
422 struct to_kill **tkc)
423{
424 struct vm_area_struct *vma;
425 struct task_struct *tsk;
426 struct prio_tree_iter iter;
427 struct address_space *mapping = page->mapping;
428
Peter Zijlstra3d48ae42011-05-24 17:12:06 -0700429 mutex_lock(&mapping->i_mmap_mutex);
Peter Zijlstra9b679322011-06-27 16:18:09 -0700430 read_lock(&tasklist_lock);
Andi Kleen6a460792009-09-16 11:50:15 +0200431 for_each_process(tsk) {
432 pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
433
434 if (!task_early_kill(tsk))
435 continue;
436
437 vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff,
438 pgoff) {
439 /*
440 * Send early kill signal to tasks where a vma covers
441 * the page but the corrupted page is not necessarily
442 * mapped it in its pte.
443 * Assume applications who requested early kill want
444 * to be informed of all such data corruptions.
445 */
446 if (vma->vm_mm == tsk->mm)
447 add_to_kill(tsk, page, vma, to_kill, tkc);
448 }
449 }
Andi Kleen6a460792009-09-16 11:50:15 +0200450 read_unlock(&tasklist_lock);
Peter Zijlstra9b679322011-06-27 16:18:09 -0700451 mutex_unlock(&mapping->i_mmap_mutex);
Andi Kleen6a460792009-09-16 11:50:15 +0200452}
453
454/*
455 * Collect the processes who have the corrupted page mapped to kill.
456 * This is done in two steps for locking reasons.
457 * First preallocate one tokill structure outside the spin locks,
458 * so that we can kill at least one process reasonably reliable.
459 */
460static void collect_procs(struct page *page, struct list_head *tokill)
461{
462 struct to_kill *tk;
463
464 if (!page->mapping)
465 return;
466
467 tk = kmalloc(sizeof(struct to_kill), GFP_NOIO);
468 if (!tk)
469 return;
470 if (PageAnon(page))
471 collect_procs_anon(page, tokill, &tk);
472 else
473 collect_procs_file(page, tokill, &tk);
474 kfree(tk);
475}
476
477/*
478 * Error handlers for various types of pages.
479 */
480
481enum outcome {
Wu Fengguangd95ea512009-12-16 12:19:58 +0100482 IGNORED, /* Error: cannot be handled */
483 FAILED, /* Error: handling failed */
Andi Kleen6a460792009-09-16 11:50:15 +0200484 DELAYED, /* Will be handled later */
Andi Kleen6a460792009-09-16 11:50:15 +0200485 RECOVERED, /* Successfully recovered */
486};
487
488static const char *action_name[] = {
Wu Fengguangd95ea512009-12-16 12:19:58 +0100489 [IGNORED] = "Ignored",
Andi Kleen6a460792009-09-16 11:50:15 +0200490 [FAILED] = "Failed",
491 [DELAYED] = "Delayed",
Andi Kleen6a460792009-09-16 11:50:15 +0200492 [RECOVERED] = "Recovered",
493};
494
495/*
Wu Fengguangdc2a1cb2009-12-16 12:19:58 +0100496 * XXX: It is possible that a page is isolated from LRU cache,
497 * and then kept in swap cache or failed to remove from page cache.
498 * The page count will stop it from being freed by unpoison.
499 * Stress tests should be aware of this memory leak problem.
500 */
501static int delete_from_lru_cache(struct page *p)
502{
503 if (!isolate_lru_page(p)) {
504 /*
505 * Clear sensible page flags, so that the buddy system won't
506 * complain when the page is unpoison-and-freed.
507 */
508 ClearPageActive(p);
509 ClearPageUnevictable(p);
510 /*
511 * drop the page count elevated by isolate_lru_page()
512 */
513 page_cache_release(p);
514 return 0;
515 }
516 return -EIO;
517}
518
519/*
Andi Kleen6a460792009-09-16 11:50:15 +0200520 * Error hit kernel page.
521 * Do nothing, try to be lucky and not touch this instead. For a few cases we
522 * could be more sophisticated.
523 */
524static int me_kernel(struct page *p, unsigned long pfn)
525{
Andi Kleen6a460792009-09-16 11:50:15 +0200526 return IGNORED;
527}
528
529/*
530 * Page in unknown state. Do nothing.
531 */
532static int me_unknown(struct page *p, unsigned long pfn)
533{
534 printk(KERN_ERR "MCE %#lx: Unknown page state\n", pfn);
535 return FAILED;
536}
537
538/*
Andi Kleen6a460792009-09-16 11:50:15 +0200539 * Clean (or cleaned) page cache page.
540 */
541static int me_pagecache_clean(struct page *p, unsigned long pfn)
542{
543 int err;
544 int ret = FAILED;
545 struct address_space *mapping;
546
Wu Fengguangdc2a1cb2009-12-16 12:19:58 +0100547 delete_from_lru_cache(p);
548
Andi Kleen6a460792009-09-16 11:50:15 +0200549 /*
550 * For anonymous pages we're done the only reference left
551 * should be the one m_f() holds.
552 */
553 if (PageAnon(p))
554 return RECOVERED;
555
556 /*
557 * Now truncate the page in the page cache. This is really
558 * more like a "temporary hole punch"
559 * Don't do this for block devices when someone else
560 * has a reference, because it could be file system metadata
561 * and that's not safe to truncate.
562 */
563 mapping = page_mapping(p);
564 if (!mapping) {
565 /*
566 * Page has been teared down in the meanwhile
567 */
568 return FAILED;
569 }
570
571 /*
572 * Truncation is a bit tricky. Enable it per file system for now.
573 *
574 * Open: to take i_mutex or not for this? Right now we don't.
575 */
576 if (mapping->a_ops->error_remove_page) {
577 err = mapping->a_ops->error_remove_page(mapping, p);
578 if (err != 0) {
579 printk(KERN_INFO "MCE %#lx: Failed to punch page: %d\n",
580 pfn, err);
581 } else if (page_has_private(p) &&
582 !try_to_release_page(p, GFP_NOIO)) {
Andi Kleenfb46e732010-09-27 23:31:30 +0200583 pr_info("MCE %#lx: failed to release buffers\n", pfn);
Andi Kleen6a460792009-09-16 11:50:15 +0200584 } else {
585 ret = RECOVERED;
586 }
587 } else {
588 /*
589 * If the file system doesn't support it just invalidate
590 * This fails on dirty or anything with private pages
591 */
592 if (invalidate_inode_page(p))
593 ret = RECOVERED;
594 else
595 printk(KERN_INFO "MCE %#lx: Failed to invalidate\n",
596 pfn);
597 }
598 return ret;
599}
600
601/*
602 * Dirty cache page page
603 * Issues: when the error hit a hole page the error is not properly
604 * propagated.
605 */
606static int me_pagecache_dirty(struct page *p, unsigned long pfn)
607{
608 struct address_space *mapping = page_mapping(p);
609
610 SetPageError(p);
611 /* TBD: print more information about the file. */
612 if (mapping) {
613 /*
614 * IO error will be reported by write(), fsync(), etc.
615 * who check the mapping.
616 * This way the application knows that something went
617 * wrong with its dirty file data.
618 *
619 * There's one open issue:
620 *
621 * The EIO will be only reported on the next IO
622 * operation and then cleared through the IO map.
623 * Normally Linux has two mechanisms to pass IO error
624 * first through the AS_EIO flag in the address space
625 * and then through the PageError flag in the page.
626 * Since we drop pages on memory failure handling the
627 * only mechanism open to use is through AS_AIO.
628 *
629 * This has the disadvantage that it gets cleared on
630 * the first operation that returns an error, while
631 * the PageError bit is more sticky and only cleared
632 * when the page is reread or dropped. If an
633 * application assumes it will always get error on
634 * fsync, but does other operations on the fd before
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300635 * and the page is dropped between then the error
Andi Kleen6a460792009-09-16 11:50:15 +0200636 * will not be properly reported.
637 *
638 * This can already happen even without hwpoisoned
639 * pages: first on metadata IO errors (which only
640 * report through AS_EIO) or when the page is dropped
641 * at the wrong time.
642 *
643 * So right now we assume that the application DTRT on
644 * the first EIO, but we're not worse than other parts
645 * of the kernel.
646 */
647 mapping_set_error(mapping, EIO);
648 }
649
650 return me_pagecache_clean(p, pfn);
651}
652
653/*
654 * Clean and dirty swap cache.
655 *
656 * Dirty swap cache page is tricky to handle. The page could live both in page
657 * cache and swap cache(ie. page is freshly swapped in). So it could be
658 * referenced concurrently by 2 types of PTEs:
659 * normal PTEs and swap PTEs. We try to handle them consistently by calling
660 * try_to_unmap(TTU_IGNORE_HWPOISON) to convert the normal PTEs to swap PTEs,
661 * and then
662 * - clear dirty bit to prevent IO
663 * - remove from LRU
664 * - but keep in the swap cache, so that when we return to it on
665 * a later page fault, we know the application is accessing
666 * corrupted data and shall be killed (we installed simple
667 * interception code in do_swap_page to catch it).
668 *
669 * Clean swap cache pages can be directly isolated. A later page fault will
670 * bring in the known good data from disk.
671 */
672static int me_swapcache_dirty(struct page *p, unsigned long pfn)
673{
Andi Kleen6a460792009-09-16 11:50:15 +0200674 ClearPageDirty(p);
675 /* Trigger EIO in shmem: */
676 ClearPageUptodate(p);
677
Wu Fengguangdc2a1cb2009-12-16 12:19:58 +0100678 if (!delete_from_lru_cache(p))
679 return DELAYED;
680 else
681 return FAILED;
Andi Kleen6a460792009-09-16 11:50:15 +0200682}
683
684static int me_swapcache_clean(struct page *p, unsigned long pfn)
685{
Andi Kleen6a460792009-09-16 11:50:15 +0200686 delete_from_swap_cache(p);
Wu Fengguange43c3af2009-09-29 13:16:20 +0800687
Wu Fengguangdc2a1cb2009-12-16 12:19:58 +0100688 if (!delete_from_lru_cache(p))
689 return RECOVERED;
690 else
691 return FAILED;
Andi Kleen6a460792009-09-16 11:50:15 +0200692}
693
694/*
695 * Huge pages. Needs work.
696 * Issues:
Naoya Horiguchi93f70f92010-05-28 09:29:20 +0900697 * - Error on hugepage is contained in hugepage unit (not in raw page unit.)
698 * To narrow down kill region to one page, we need to break up pmd.
Andi Kleen6a460792009-09-16 11:50:15 +0200699 */
700static int me_huge_page(struct page *p, unsigned long pfn)
701{
Naoya Horiguchi6de2b1a2010-09-08 10:19:36 +0900702 int res = 0;
Naoya Horiguchi93f70f92010-05-28 09:29:20 +0900703 struct page *hpage = compound_head(p);
704 /*
705 * We can safely recover from error on free or reserved (i.e.
706 * not in-use) hugepage by dequeuing it from freelist.
707 * To check whether a hugepage is in-use or not, we can't use
708 * page->lru because it can be used in other hugepage operations,
709 * such as __unmap_hugepage_range() and gather_surplus_pages().
710 * So instead we use page_mapping() and PageAnon().
711 * We assume that this function is called with page lock held,
712 * so there is no race between isolation and mapping/unmapping.
713 */
714 if (!(page_mapping(hpage) || PageAnon(hpage))) {
Naoya Horiguchi6de2b1a2010-09-08 10:19:36 +0900715 res = dequeue_hwpoisoned_huge_page(hpage);
716 if (!res)
717 return RECOVERED;
Naoya Horiguchi93f70f92010-05-28 09:29:20 +0900718 }
719 return DELAYED;
Andi Kleen6a460792009-09-16 11:50:15 +0200720}
721
722/*
723 * Various page states we can handle.
724 *
725 * A page state is defined by its current page->flags bits.
726 * The table matches them in order and calls the right handler.
727 *
728 * This is quite tricky because we can access page at any time
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300729 * in its live cycle, so all accesses have to be extremely careful.
Andi Kleen6a460792009-09-16 11:50:15 +0200730 *
731 * This is not complete. More states could be added.
732 * For any missing state don't attempt recovery.
733 */
734
735#define dirty (1UL << PG_dirty)
736#define sc (1UL << PG_swapcache)
737#define unevict (1UL << PG_unevictable)
738#define mlock (1UL << PG_mlocked)
739#define writeback (1UL << PG_writeback)
740#define lru (1UL << PG_lru)
741#define swapbacked (1UL << PG_swapbacked)
742#define head (1UL << PG_head)
743#define tail (1UL << PG_tail)
744#define compound (1UL << PG_compound)
745#define slab (1UL << PG_slab)
Andi Kleen6a460792009-09-16 11:50:15 +0200746#define reserved (1UL << PG_reserved)
747
748static struct page_state {
749 unsigned long mask;
750 unsigned long res;
751 char *msg;
752 int (*action)(struct page *p, unsigned long pfn);
753} error_states[] = {
Wu Fengguangd95ea512009-12-16 12:19:58 +0100754 { reserved, reserved, "reserved kernel", me_kernel },
Wu Fengguang95d01fc2009-12-16 12:19:58 +0100755 /*
756 * free pages are specially detected outside this table:
757 * PG_buddy pages only make a small fraction of all free pages.
758 */
Andi Kleen6a460792009-09-16 11:50:15 +0200759
760 /*
761 * Could in theory check if slab page is free or if we can drop
762 * currently unused objects without touching them. But just
763 * treat it as standard kernel for now.
764 */
765 { slab, slab, "kernel slab", me_kernel },
766
767#ifdef CONFIG_PAGEFLAGS_EXTENDED
768 { head, head, "huge", me_huge_page },
769 { tail, tail, "huge", me_huge_page },
770#else
771 { compound, compound, "huge", me_huge_page },
772#endif
773
774 { sc|dirty, sc|dirty, "swapcache", me_swapcache_dirty },
775 { sc|dirty, sc, "swapcache", me_swapcache_clean },
776
777 { unevict|dirty, unevict|dirty, "unevictable LRU", me_pagecache_dirty},
778 { unevict, unevict, "unevictable LRU", me_pagecache_clean},
779
Andi Kleen6a460792009-09-16 11:50:15 +0200780 { mlock|dirty, mlock|dirty, "mlocked LRU", me_pagecache_dirty },
781 { mlock, mlock, "mlocked LRU", me_pagecache_clean },
Andi Kleen6a460792009-09-16 11:50:15 +0200782
783 { lru|dirty, lru|dirty, "LRU", me_pagecache_dirty },
784 { lru|dirty, lru, "clean LRU", me_pagecache_clean },
Andi Kleen6a460792009-09-16 11:50:15 +0200785
786 /*
787 * Catchall entry: must be at end.
788 */
789 { 0, 0, "unknown page state", me_unknown },
790};
791
Andi Kleen2326c462009-12-16 12:20:00 +0100792#undef dirty
793#undef sc
794#undef unevict
795#undef mlock
796#undef writeback
797#undef lru
798#undef swapbacked
799#undef head
800#undef tail
801#undef compound
802#undef slab
803#undef reserved
804
Andi Kleen6a460792009-09-16 11:50:15 +0200805static void action_result(unsigned long pfn, char *msg, int result)
806{
Wu Fengguanga7560fc2009-12-16 12:19:57 +0100807 struct page *page = pfn_to_page(pfn);
Andi Kleen6a460792009-09-16 11:50:15 +0200808
809 printk(KERN_ERR "MCE %#lx: %s%s page recovery: %s\n",
810 pfn,
Wu Fengguanga7560fc2009-12-16 12:19:57 +0100811 PageDirty(page) ? "dirty " : "",
Andi Kleen6a460792009-09-16 11:50:15 +0200812 msg, action_name[result]);
813}
814
815static int page_action(struct page_state *ps, struct page *p,
Wu Fengguangbd1ce5f2009-12-16 12:19:57 +0100816 unsigned long pfn)
Andi Kleen6a460792009-09-16 11:50:15 +0200817{
818 int result;
Wu Fengguang7456b042009-10-19 08:15:01 +0200819 int count;
Andi Kleen6a460792009-09-16 11:50:15 +0200820
821 result = ps->action(p, pfn);
822 action_result(pfn, ps->msg, result);
Wu Fengguang7456b042009-10-19 08:15:01 +0200823
Wu Fengguangbd1ce5f2009-12-16 12:19:57 +0100824 count = page_count(p) - 1;
Wu Fengguang138ce282009-12-16 12:19:58 +0100825 if (ps->action == me_swapcache_dirty && result == DELAYED)
826 count--;
827 if (count != 0) {
Andi Kleen6a460792009-09-16 11:50:15 +0200828 printk(KERN_ERR
829 "MCE %#lx: %s page still referenced by %d users\n",
Wu Fengguang7456b042009-10-19 08:15:01 +0200830 pfn, ps->msg, count);
Wu Fengguang138ce282009-12-16 12:19:58 +0100831 result = FAILED;
832 }
Andi Kleen6a460792009-09-16 11:50:15 +0200833
834 /* Could do more checks here if page looks ok */
835 /*
836 * Could adjust zone counters here to correct for the missing page.
837 */
838
Wu Fengguang138ce282009-12-16 12:19:58 +0100839 return (result == RECOVERED || result == DELAYED) ? 0 : -EBUSY;
Andi Kleen6a460792009-09-16 11:50:15 +0200840}
841
Andi Kleen6a460792009-09-16 11:50:15 +0200842/*
843 * Do all that is necessary to remove user space mappings. Unmap
844 * the pages and send SIGBUS to the processes if the data was dirty.
845 */
Wu Fengguang1668bfd2009-12-16 12:19:58 +0100846static int hwpoison_user_mappings(struct page *p, unsigned long pfn,
Andi Kleen6a460792009-09-16 11:50:15 +0200847 int trapno)
848{
849 enum ttu_flags ttu = TTU_UNMAP | TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS;
850 struct address_space *mapping;
851 LIST_HEAD(tokill);
852 int ret;
Andi Kleen6a460792009-09-16 11:50:15 +0200853 int kill = 1;
Naoya Horiguchi7af446a2010-05-28 09:29:17 +0900854 struct page *hpage = compound_head(p);
Jin Dongminga6d30dd2011-02-01 15:52:40 -0800855 struct page *ppage;
Andi Kleen6a460792009-09-16 11:50:15 +0200856
Wu Fengguang1668bfd2009-12-16 12:19:58 +0100857 if (PageReserved(p) || PageSlab(p))
858 return SWAP_SUCCESS;
Andi Kleen6a460792009-09-16 11:50:15 +0200859
Andi Kleen6a460792009-09-16 11:50:15 +0200860 /*
861 * This check implies we don't kill processes if their pages
862 * are in the swap cache early. Those are always late kills.
863 */
Naoya Horiguchi7af446a2010-05-28 09:29:17 +0900864 if (!page_mapped(hpage))
Wu Fengguang1668bfd2009-12-16 12:19:58 +0100865 return SWAP_SUCCESS;
866
Naoya Horiguchi7af446a2010-05-28 09:29:17 +0900867 if (PageKsm(p))
Wu Fengguang1668bfd2009-12-16 12:19:58 +0100868 return SWAP_FAIL;
Andi Kleen6a460792009-09-16 11:50:15 +0200869
870 if (PageSwapCache(p)) {
871 printk(KERN_ERR
872 "MCE %#lx: keeping poisoned page in swap cache\n", pfn);
873 ttu |= TTU_IGNORE_HWPOISON;
874 }
875
876 /*
877 * Propagate the dirty bit from PTEs to struct page first, because we
878 * need this to decide if we should kill or just drop the page.
Wu Fengguangdb0480b2009-12-16 12:19:58 +0100879 * XXX: the dirty test could be racy: set_page_dirty() may not always
880 * be called inside page lock (it's recommended but not enforced).
Andi Kleen6a460792009-09-16 11:50:15 +0200881 */
Naoya Horiguchi7af446a2010-05-28 09:29:17 +0900882 mapping = page_mapping(hpage);
883 if (!PageDirty(hpage) && mapping &&
884 mapping_cap_writeback_dirty(mapping)) {
885 if (page_mkclean(hpage)) {
886 SetPageDirty(hpage);
Andi Kleen6a460792009-09-16 11:50:15 +0200887 } else {
888 kill = 0;
889 ttu |= TTU_IGNORE_HWPOISON;
890 printk(KERN_INFO
891 "MCE %#lx: corrupted page was clean: dropped without side effects\n",
892 pfn);
893 }
894 }
895
Jin Dongminga6d30dd2011-02-01 15:52:40 -0800896 /*
897 * ppage: poisoned page
898 * if p is regular page(4k page)
899 * ppage == real poisoned page;
900 * else p is hugetlb or THP, ppage == head page.
901 */
902 ppage = hpage;
903
Jin Dongmingefeda7a2011-02-01 15:52:39 -0800904 if (PageTransHuge(hpage)) {
905 /*
906 * Verify that this isn't a hugetlbfs head page, the check for
907 * PageAnon is just for avoid tripping a split_huge_page
908 * internal debug check, as split_huge_page refuses to deal with
909 * anything that isn't an anon page. PageAnon can't go away fro
910 * under us because we hold a refcount on the hpage, without a
911 * refcount on the hpage. split_huge_page can't be safely called
912 * in the first place, having a refcount on the tail isn't
913 * enough * to be safe.
914 */
915 if (!PageHuge(hpage) && PageAnon(hpage)) {
916 if (unlikely(split_huge_page(hpage))) {
917 /*
918 * FIXME: if splitting THP is failed, it is
919 * better to stop the following operation rather
920 * than causing panic by unmapping. System might
921 * survive if the page is freed later.
922 */
923 printk(KERN_INFO
924 "MCE %#lx: failed to split THP\n", pfn);
925
926 BUG_ON(!PageHWPoison(p));
927 return SWAP_FAIL;
928 }
Jin Dongminga6d30dd2011-02-01 15:52:40 -0800929 /* THP is split, so ppage should be the real poisoned page. */
930 ppage = p;
Jin Dongmingefeda7a2011-02-01 15:52:39 -0800931 }
932 }
933
Andi Kleen6a460792009-09-16 11:50:15 +0200934 /*
935 * First collect all the processes that have the page
936 * mapped in dirty form. This has to be done before try_to_unmap,
937 * because ttu takes the rmap data structures down.
938 *
939 * Error handling: We ignore errors here because
940 * there's nothing that can be done.
941 */
942 if (kill)
Jin Dongminga6d30dd2011-02-01 15:52:40 -0800943 collect_procs(ppage, &tokill);
Andi Kleen6a460792009-09-16 11:50:15 +0200944
Jin Dongminga6d30dd2011-02-01 15:52:40 -0800945 if (hpage != ppage)
Jens Axboe7eaceac2011-03-10 08:52:07 +0100946 lock_page(ppage);
Jin Dongminga6d30dd2011-02-01 15:52:40 -0800947
948 ret = try_to_unmap(ppage, ttu);
Andi Kleen6a460792009-09-16 11:50:15 +0200949 if (ret != SWAP_SUCCESS)
950 printk(KERN_ERR "MCE %#lx: failed to unmap page (mapcount=%d)\n",
Jin Dongminga6d30dd2011-02-01 15:52:40 -0800951 pfn, page_mapcount(ppage));
952
953 if (hpage != ppage)
954 unlock_page(ppage);
Andi Kleen6a460792009-09-16 11:50:15 +0200955
956 /*
957 * Now that the dirty bit has been propagated to the
958 * struct page and all unmaps done we can decide if
959 * killing is needed or not. Only kill when the page
960 * was dirty, otherwise the tokill list is merely
961 * freed. When there was a problem unmapping earlier
962 * use a more force-full uncatchable kill to prevent
963 * any accesses to the poisoned memory.
964 */
Jin Dongminga6d30dd2011-02-01 15:52:40 -0800965 kill_procs_ao(&tokill, !!PageDirty(ppage), trapno,
Andi Kleen0d9ee6a2010-09-27 22:03:33 +0200966 ret != SWAP_SUCCESS, p, pfn);
Wu Fengguang1668bfd2009-12-16 12:19:58 +0100967
968 return ret;
Andi Kleen6a460792009-09-16 11:50:15 +0200969}
970
Naoya Horiguchi7013feb2010-05-28 09:29:18 +0900971static void set_page_hwpoison_huge_page(struct page *hpage)
972{
973 int i;
Andrea Arcangeli37c2ac72011-01-13 15:47:16 -0800974 int nr_pages = 1 << compound_trans_order(hpage);
Naoya Horiguchi7013feb2010-05-28 09:29:18 +0900975 for (i = 0; i < nr_pages; i++)
976 SetPageHWPoison(hpage + i);
977}
978
979static void clear_page_hwpoison_huge_page(struct page *hpage)
980{
981 int i;
Andrea Arcangeli37c2ac72011-01-13 15:47:16 -0800982 int nr_pages = 1 << compound_trans_order(hpage);
Naoya Horiguchi7013feb2010-05-28 09:29:18 +0900983 for (i = 0; i < nr_pages; i++)
984 ClearPageHWPoison(hpage + i);
985}
986
Andi Kleen82ba0112009-12-16 12:19:57 +0100987int __memory_failure(unsigned long pfn, int trapno, int flags)
Andi Kleen6a460792009-09-16 11:50:15 +0200988{
989 struct page_state *ps;
990 struct page *p;
Naoya Horiguchi7af446a2010-05-28 09:29:17 +0900991 struct page *hpage;
Andi Kleen6a460792009-09-16 11:50:15 +0200992 int res;
Naoya Horiguchic9fbdd52010-05-28 09:29:19 +0900993 unsigned int nr_pages;
Andi Kleen6a460792009-09-16 11:50:15 +0200994
995 if (!sysctl_memory_failure_recovery)
996 panic("Memory failure from trap %d on page %lx", trapno, pfn);
997
998 if (!pfn_valid(pfn)) {
Wu Fengguanga7560fc2009-12-16 12:19:57 +0100999 printk(KERN_ERR
1000 "MCE %#lx: memory outside kernel control\n",
1001 pfn);
1002 return -ENXIO;
Andi Kleen6a460792009-09-16 11:50:15 +02001003 }
1004
1005 p = pfn_to_page(pfn);
Naoya Horiguchi7af446a2010-05-28 09:29:17 +09001006 hpage = compound_head(p);
Andi Kleen6a460792009-09-16 11:50:15 +02001007 if (TestSetPageHWPoison(p)) {
Wu Fengguangd95ea512009-12-16 12:19:58 +01001008 printk(KERN_ERR "MCE %#lx: already hardware poisoned\n", pfn);
Andi Kleen6a460792009-09-16 11:50:15 +02001009 return 0;
1010 }
1011
Andrea Arcangeli37c2ac72011-01-13 15:47:16 -08001012 nr_pages = 1 << compound_trans_order(hpage);
Naoya Horiguchic9fbdd52010-05-28 09:29:19 +09001013 atomic_long_add(nr_pages, &mce_bad_pages);
Andi Kleen6a460792009-09-16 11:50:15 +02001014
1015 /*
1016 * We need/can do nothing about count=0 pages.
1017 * 1) it's a free page, and therefore in safe hand:
1018 * prep_new_page() will be the gate keeper.
Naoya Horiguchi8c6c2ec2010-09-08 10:19:38 +09001019 * 2) it's a free hugepage, which is also safe:
1020 * an affected hugepage will be dequeued from hugepage freelist,
1021 * so there's no concern about reusing it ever after.
1022 * 3) it's part of a non-compound high order page.
Andi Kleen6a460792009-09-16 11:50:15 +02001023 * Implies some kernel user: cannot stop them from
1024 * R/W the page; let's pray that the page has been
1025 * used and will be freed some time later.
1026 * In fact it's dangerous to directly bump up page count from 0,
1027 * that may make page_freeze_refs()/page_unfreeze_refs() mismatch.
1028 */
Andi Kleen82ba0112009-12-16 12:19:57 +01001029 if (!(flags & MF_COUNT_INCREASED) &&
Naoya Horiguchi7af446a2010-05-28 09:29:17 +09001030 !get_page_unless_zero(hpage)) {
Wu Fengguang8d22ba12009-12-16 12:19:58 +01001031 if (is_free_buddy_page(p)) {
1032 action_result(pfn, "free buddy", DELAYED);
1033 return 0;
Naoya Horiguchi8c6c2ec2010-09-08 10:19:38 +09001034 } else if (PageHuge(hpage)) {
1035 /*
1036 * Check "just unpoisoned", "filter hit", and
1037 * "race with other subpage."
1038 */
Jens Axboe7eaceac2011-03-10 08:52:07 +01001039 lock_page(hpage);
Naoya Horiguchi8c6c2ec2010-09-08 10:19:38 +09001040 if (!PageHWPoison(hpage)
1041 || (hwpoison_filter(p) && TestClearPageHWPoison(p))
1042 || (p != hpage && TestSetPageHWPoison(hpage))) {
1043 atomic_long_sub(nr_pages, &mce_bad_pages);
1044 return 0;
1045 }
1046 set_page_hwpoison_huge_page(hpage);
1047 res = dequeue_hwpoisoned_huge_page(hpage);
1048 action_result(pfn, "free huge",
1049 res ? IGNORED : DELAYED);
1050 unlock_page(hpage);
1051 return res;
Wu Fengguang8d22ba12009-12-16 12:19:58 +01001052 } else {
1053 action_result(pfn, "high order kernel", IGNORED);
1054 return -EBUSY;
1055 }
Andi Kleen6a460792009-09-16 11:50:15 +02001056 }
1057
1058 /*
Wu Fengguange43c3af2009-09-29 13:16:20 +08001059 * We ignore non-LRU pages for good reasons.
1060 * - PG_locked is only well defined for LRU pages and a few others
1061 * - to avoid races with __set_page_locked()
1062 * - to avoid races with __SetPageSlab*() (and more non-atomic ops)
1063 * The check (unnecessarily) ignores LRU pages being isolated and
1064 * walked by the page reclaim code, however that's not a big loss.
1065 */
Jin Dongmingaf241a02011-02-01 15:52:41 -08001066 if (!PageHuge(p) && !PageTransCompound(p)) {
1067 if (!PageLRU(p))
1068 shake_page(p, 0);
1069 if (!PageLRU(p)) {
1070 /*
1071 * shake_page could have turned it free.
1072 */
1073 if (is_free_buddy_page(p)) {
1074 action_result(pfn, "free buddy, 2nd try",
1075 DELAYED);
1076 return 0;
1077 }
1078 action_result(pfn, "non LRU", IGNORED);
1079 put_page(p);
1080 return -EBUSY;
Andi Kleen0474a602009-12-16 12:20:00 +01001081 }
Wu Fengguange43c3af2009-09-29 13:16:20 +08001082 }
Wu Fengguange43c3af2009-09-29 13:16:20 +08001083
1084 /*
Andi Kleen6a460792009-09-16 11:50:15 +02001085 * Lock the page and wait for writeback to finish.
1086 * It's very difficult to mess with pages currently under IO
1087 * and in many cases impossible, so we just avoid it here.
1088 */
Jens Axboe7eaceac2011-03-10 08:52:07 +01001089 lock_page(hpage);
Wu Fengguang847ce402009-12-16 12:19:58 +01001090
1091 /*
1092 * unpoison always clear PG_hwpoison inside page lock
1093 */
1094 if (!PageHWPoison(p)) {
Wu Fengguangd95ea512009-12-16 12:19:58 +01001095 printk(KERN_ERR "MCE %#lx: just unpoisoned\n", pfn);
Wu Fengguang847ce402009-12-16 12:19:58 +01001096 res = 0;
1097 goto out;
1098 }
Wu Fengguang7c116f22009-12-16 12:19:59 +01001099 if (hwpoison_filter(p)) {
1100 if (TestClearPageHWPoison(p))
Naoya Horiguchic9fbdd52010-05-28 09:29:19 +09001101 atomic_long_sub(nr_pages, &mce_bad_pages);
Naoya Horiguchi7af446a2010-05-28 09:29:17 +09001102 unlock_page(hpage);
1103 put_page(hpage);
Wu Fengguang7c116f22009-12-16 12:19:59 +01001104 return 0;
1105 }
Wu Fengguang847ce402009-12-16 12:19:58 +01001106
Naoya Horiguchi7013feb2010-05-28 09:29:18 +09001107 /*
1108 * For error on the tail page, we should set PG_hwpoison
1109 * on the head page to show that the hugepage is hwpoisoned
1110 */
Jin Dongminga6d30dd2011-02-01 15:52:40 -08001111 if (PageHuge(p) && PageTail(p) && TestSetPageHWPoison(hpage)) {
Naoya Horiguchi7013feb2010-05-28 09:29:18 +09001112 action_result(pfn, "hugepage already hardware poisoned",
1113 IGNORED);
1114 unlock_page(hpage);
1115 put_page(hpage);
1116 return 0;
1117 }
1118 /*
1119 * Set PG_hwpoison on all pages in an error hugepage,
1120 * because containment is done in hugepage unit for now.
1121 * Since we have done TestSetPageHWPoison() for the head page with
1122 * page lock held, we can safely set PG_hwpoison bits on tail pages.
1123 */
1124 if (PageHuge(p))
1125 set_page_hwpoison_huge_page(hpage);
1126
Andi Kleen6a460792009-09-16 11:50:15 +02001127 wait_on_page_writeback(p);
1128
1129 /*
1130 * Now take care of user space mappings.
Minchan Kime64a7822011-03-22 16:32:44 -07001131 * Abort on fail: __delete_from_page_cache() assumes unmapped page.
Andi Kleen6a460792009-09-16 11:50:15 +02001132 */
Wu Fengguang1668bfd2009-12-16 12:19:58 +01001133 if (hwpoison_user_mappings(p, pfn, trapno) != SWAP_SUCCESS) {
1134 printk(KERN_ERR "MCE %#lx: cannot unmap page, give up\n", pfn);
1135 res = -EBUSY;
1136 goto out;
1137 }
Andi Kleen6a460792009-09-16 11:50:15 +02001138
1139 /*
1140 * Torn down by someone else?
1141 */
Wu Fengguangdc2a1cb2009-12-16 12:19:58 +01001142 if (PageLRU(p) && !PageSwapCache(p) && p->mapping == NULL) {
Andi Kleen6a460792009-09-16 11:50:15 +02001143 action_result(pfn, "already truncated LRU", IGNORED);
Wu Fengguangd95ea512009-12-16 12:19:58 +01001144 res = -EBUSY;
Andi Kleen6a460792009-09-16 11:50:15 +02001145 goto out;
1146 }
1147
1148 res = -EBUSY;
1149 for (ps = error_states;; ps++) {
Wu Fengguangdc2a1cb2009-12-16 12:19:58 +01001150 if ((p->flags & ps->mask) == ps->res) {
Wu Fengguangbd1ce5f2009-12-16 12:19:57 +01001151 res = page_action(ps, p, pfn);
Andi Kleen6a460792009-09-16 11:50:15 +02001152 break;
1153 }
1154 }
1155out:
Naoya Horiguchi7af446a2010-05-28 09:29:17 +09001156 unlock_page(hpage);
Andi Kleen6a460792009-09-16 11:50:15 +02001157 return res;
1158}
1159EXPORT_SYMBOL_GPL(__memory_failure);
1160
1161/**
1162 * memory_failure - Handle memory failure of a page.
1163 * @pfn: Page Number of the corrupted page
1164 * @trapno: Trap number reported in the signal to user space.
1165 *
1166 * This function is called by the low level machine check code
1167 * of an architecture when it detects hardware memory corruption
1168 * of a page. It tries its best to recover, which includes
1169 * dropping pages, killing processes etc.
1170 *
1171 * The function is primarily of use for corruptions that
1172 * happen outside the current execution context (e.g. when
1173 * detected by a background scrubber)
1174 *
1175 * Must run in process context (e.g. a work queue) with interrupts
1176 * enabled and no spinlocks hold.
1177 */
1178void memory_failure(unsigned long pfn, int trapno)
1179{
1180 __memory_failure(pfn, trapno, 0);
1181}
Wu Fengguang847ce402009-12-16 12:19:58 +01001182
Huang Yingea8f5fb2011-07-13 13:14:27 +08001183#define MEMORY_FAILURE_FIFO_ORDER 4
1184#define MEMORY_FAILURE_FIFO_SIZE (1 << MEMORY_FAILURE_FIFO_ORDER)
1185
1186struct memory_failure_entry {
1187 unsigned long pfn;
1188 int trapno;
1189 int flags;
1190};
1191
1192struct memory_failure_cpu {
1193 DECLARE_KFIFO(fifo, struct memory_failure_entry,
1194 MEMORY_FAILURE_FIFO_SIZE);
1195 spinlock_t lock;
1196 struct work_struct work;
1197};
1198
1199static DEFINE_PER_CPU(struct memory_failure_cpu, memory_failure_cpu);
1200
1201/**
1202 * memory_failure_queue - Schedule handling memory failure of a page.
1203 * @pfn: Page Number of the corrupted page
1204 * @trapno: Trap number reported in the signal to user space.
1205 * @flags: Flags for memory failure handling
1206 *
1207 * This function is called by the low level hardware error handler
1208 * when it detects hardware memory corruption of a page. It schedules
1209 * the recovering of error page, including dropping pages, killing
1210 * processes etc.
1211 *
1212 * The function is primarily of use for corruptions that
1213 * happen outside the current execution context (e.g. when
1214 * detected by a background scrubber)
1215 *
1216 * Can run in IRQ context.
1217 */
1218void memory_failure_queue(unsigned long pfn, int trapno, int flags)
1219{
1220 struct memory_failure_cpu *mf_cpu;
1221 unsigned long proc_flags;
1222 struct memory_failure_entry entry = {
1223 .pfn = pfn,
1224 .trapno = trapno,
1225 .flags = flags,
1226 };
1227
1228 mf_cpu = &get_cpu_var(memory_failure_cpu);
1229 spin_lock_irqsave(&mf_cpu->lock, proc_flags);
1230 if (kfifo_put(&mf_cpu->fifo, &entry))
1231 schedule_work_on(smp_processor_id(), &mf_cpu->work);
1232 else
1233 pr_err("Memory failure: buffer overflow when queuing memory failure at 0x%#lx\n",
1234 pfn);
1235 spin_unlock_irqrestore(&mf_cpu->lock, proc_flags);
1236 put_cpu_var(memory_failure_cpu);
1237}
1238EXPORT_SYMBOL_GPL(memory_failure_queue);
1239
1240static void memory_failure_work_func(struct work_struct *work)
1241{
1242 struct memory_failure_cpu *mf_cpu;
1243 struct memory_failure_entry entry = { 0, };
1244 unsigned long proc_flags;
1245 int gotten;
1246
1247 mf_cpu = &__get_cpu_var(memory_failure_cpu);
1248 for (;;) {
1249 spin_lock_irqsave(&mf_cpu->lock, proc_flags);
1250 gotten = kfifo_get(&mf_cpu->fifo, &entry);
1251 spin_unlock_irqrestore(&mf_cpu->lock, proc_flags);
1252 if (!gotten)
1253 break;
1254 __memory_failure(entry.pfn, entry.trapno, entry.flags);
1255 }
1256}
1257
1258static int __init memory_failure_init(void)
1259{
1260 struct memory_failure_cpu *mf_cpu;
1261 int cpu;
1262
1263 for_each_possible_cpu(cpu) {
1264 mf_cpu = &per_cpu(memory_failure_cpu, cpu);
1265 spin_lock_init(&mf_cpu->lock);
1266 INIT_KFIFO(mf_cpu->fifo);
1267 INIT_WORK(&mf_cpu->work, memory_failure_work_func);
1268 }
1269
1270 return 0;
1271}
1272core_initcall(memory_failure_init);
1273
Wu Fengguang847ce402009-12-16 12:19:58 +01001274/**
1275 * unpoison_memory - Unpoison a previously poisoned page
1276 * @pfn: Page number of the to be unpoisoned page
1277 *
1278 * Software-unpoison a page that has been poisoned by
1279 * memory_failure() earlier.
1280 *
1281 * This is only done on the software-level, so it only works
1282 * for linux injected failures, not real hardware failures
1283 *
1284 * Returns 0 for success, otherwise -errno.
1285 */
1286int unpoison_memory(unsigned long pfn)
1287{
1288 struct page *page;
1289 struct page *p;
1290 int freeit = 0;
Naoya Horiguchic9fbdd52010-05-28 09:29:19 +09001291 unsigned int nr_pages;
Wu Fengguang847ce402009-12-16 12:19:58 +01001292
1293 if (!pfn_valid(pfn))
1294 return -ENXIO;
1295
1296 p = pfn_to_page(pfn);
1297 page = compound_head(p);
1298
1299 if (!PageHWPoison(p)) {
Andi Kleenfb46e732010-09-27 23:31:30 +02001300 pr_info("MCE: Page was already unpoisoned %#lx\n", pfn);
Wu Fengguang847ce402009-12-16 12:19:58 +01001301 return 0;
1302 }
1303
Andrea Arcangeli37c2ac72011-01-13 15:47:16 -08001304 nr_pages = 1 << compound_trans_order(page);
Naoya Horiguchic9fbdd52010-05-28 09:29:19 +09001305
Wu Fengguang847ce402009-12-16 12:19:58 +01001306 if (!get_page_unless_zero(page)) {
Naoya Horiguchi8c6c2ec2010-09-08 10:19:38 +09001307 /*
1308 * Since HWPoisoned hugepage should have non-zero refcount,
1309 * race between memory failure and unpoison seems to happen.
1310 * In such case unpoison fails and memory failure runs
1311 * to the end.
1312 */
1313 if (PageHuge(page)) {
Dean Nelsondd73e852011-10-31 17:09:04 -07001314 pr_info("MCE: Memory failure is now running on free hugepage %#lx\n", pfn);
Naoya Horiguchi8c6c2ec2010-09-08 10:19:38 +09001315 return 0;
1316 }
Wu Fengguang847ce402009-12-16 12:19:58 +01001317 if (TestClearPageHWPoison(p))
Naoya Horiguchic9fbdd52010-05-28 09:29:19 +09001318 atomic_long_sub(nr_pages, &mce_bad_pages);
Andi Kleenfb46e732010-09-27 23:31:30 +02001319 pr_info("MCE: Software-unpoisoned free page %#lx\n", pfn);
Wu Fengguang847ce402009-12-16 12:19:58 +01001320 return 0;
1321 }
1322
Jens Axboe7eaceac2011-03-10 08:52:07 +01001323 lock_page(page);
Wu Fengguang847ce402009-12-16 12:19:58 +01001324 /*
1325 * This test is racy because PG_hwpoison is set outside of page lock.
1326 * That's acceptable because that won't trigger kernel panic. Instead,
1327 * the PG_hwpoison page will be caught and isolated on the entrance to
1328 * the free buddy page pool.
1329 */
Naoya Horiguchic9fbdd52010-05-28 09:29:19 +09001330 if (TestClearPageHWPoison(page)) {
Andi Kleenfb46e732010-09-27 23:31:30 +02001331 pr_info("MCE: Software-unpoisoned page %#lx\n", pfn);
Naoya Horiguchic9fbdd52010-05-28 09:29:19 +09001332 atomic_long_sub(nr_pages, &mce_bad_pages);
Wu Fengguang847ce402009-12-16 12:19:58 +01001333 freeit = 1;
Naoya Horiguchi6a901812010-09-08 10:19:40 +09001334 if (PageHuge(page))
1335 clear_page_hwpoison_huge_page(page);
Wu Fengguang847ce402009-12-16 12:19:58 +01001336 }
1337 unlock_page(page);
1338
1339 put_page(page);
1340 if (freeit)
1341 put_page(page);
1342
1343 return 0;
1344}
1345EXPORT_SYMBOL(unpoison_memory);
Andi Kleenfacb6012009-12-16 12:20:00 +01001346
1347static struct page *new_page(struct page *p, unsigned long private, int **x)
1348{
Andi Kleen12686d12009-12-16 12:20:01 +01001349 int nid = page_to_nid(p);
Naoya Horiguchid950b952010-09-08 10:19:39 +09001350 if (PageHuge(p))
1351 return alloc_huge_page_node(page_hstate(compound_head(p)),
1352 nid);
1353 else
1354 return alloc_pages_exact_node(nid, GFP_HIGHUSER_MOVABLE, 0);
Andi Kleenfacb6012009-12-16 12:20:00 +01001355}
1356
1357/*
1358 * Safely get reference count of an arbitrary page.
1359 * Returns 0 for a free page, -EIO for a zero refcount page
1360 * that is not free, and 1 for any other page type.
1361 * For 1 the page is returned with increased page count, otherwise not.
1362 */
1363static int get_any_page(struct page *p, unsigned long pfn, int flags)
1364{
1365 int ret;
1366
1367 if (flags & MF_COUNT_INCREASED)
1368 return 1;
1369
1370 /*
KOSAKI Motohiro20d6c962010-12-02 14:31:19 -08001371 * The lock_memory_hotplug prevents a race with memory hotplug.
Andi Kleenfacb6012009-12-16 12:20:00 +01001372 * This is a big hammer, a better would be nicer.
1373 */
KOSAKI Motohiro20d6c962010-12-02 14:31:19 -08001374 lock_memory_hotplug();
Andi Kleenfacb6012009-12-16 12:20:00 +01001375
1376 /*
1377 * Isolate the page, so that it doesn't get reallocated if it
1378 * was free.
1379 */
1380 set_migratetype_isolate(p);
Naoya Horiguchid950b952010-09-08 10:19:39 +09001381 /*
1382 * When the target page is a free hugepage, just remove it
1383 * from free hugepage list.
1384 */
Andi Kleenfacb6012009-12-16 12:20:00 +01001385 if (!get_page_unless_zero(compound_head(p))) {
Naoya Horiguchid950b952010-09-08 10:19:39 +09001386 if (PageHuge(p)) {
Andi Kleen46e387b2010-10-22 17:40:48 +02001387 pr_info("get_any_page: %#lx free huge page\n", pfn);
Naoya Horiguchid950b952010-09-08 10:19:39 +09001388 ret = dequeue_hwpoisoned_huge_page(compound_head(p));
1389 } else if (is_free_buddy_page(p)) {
Andi Kleenfb46e732010-09-27 23:31:30 +02001390 pr_info("get_any_page: %#lx free buddy page\n", pfn);
Andi Kleenfacb6012009-12-16 12:20:00 +01001391 /* Set hwpoison bit while page is still isolated */
1392 SetPageHWPoison(p);
1393 ret = 0;
1394 } else {
Andi Kleenfb46e732010-09-27 23:31:30 +02001395 pr_info("get_any_page: %#lx: unknown zero refcount page type %lx\n",
Andi Kleenfacb6012009-12-16 12:20:00 +01001396 pfn, p->flags);
1397 ret = -EIO;
1398 }
1399 } else {
1400 /* Not a free page */
1401 ret = 1;
1402 }
1403 unset_migratetype_isolate(p);
KOSAKI Motohiro20d6c962010-12-02 14:31:19 -08001404 unlock_memory_hotplug();
Andi Kleenfacb6012009-12-16 12:20:00 +01001405 return ret;
1406}
1407
Naoya Horiguchid950b952010-09-08 10:19:39 +09001408static int soft_offline_huge_page(struct page *page, int flags)
1409{
1410 int ret;
1411 unsigned long pfn = page_to_pfn(page);
1412 struct page *hpage = compound_head(page);
1413 LIST_HEAD(pagelist);
1414
1415 ret = get_any_page(page, pfn, flags);
1416 if (ret < 0)
1417 return ret;
1418 if (ret == 0)
1419 goto done;
1420
1421 if (PageHWPoison(hpage)) {
1422 put_page(hpage);
Dean Nelsondd73e852011-10-31 17:09:04 -07001423 pr_info("soft offline: %#lx hugepage already poisoned\n", pfn);
Naoya Horiguchid950b952010-09-08 10:19:39 +09001424 return -EBUSY;
1425 }
1426
1427 /* Keep page count to indicate a given hugepage is isolated. */
1428
1429 list_add(&hpage->lru, &pagelist);
Mel Gorman77f1fe62011-01-13 15:45:57 -08001430 ret = migrate_huge_pages(&pagelist, new_page, MPOL_MF_MOVE_ALL, 0,
1431 true);
Naoya Horiguchid950b952010-09-08 10:19:39 +09001432 if (ret) {
Minchan Kim48db54e2011-02-01 15:52:33 -08001433 struct page *page1, *page2;
1434 list_for_each_entry_safe(page1, page2, &pagelist, lru)
1435 put_page(page1);
1436
Dean Nelsondd73e852011-10-31 17:09:04 -07001437 pr_info("soft offline: %#lx: migration failed %d, type %lx\n",
1438 pfn, ret, page->flags);
Naoya Horiguchid950b952010-09-08 10:19:39 +09001439 if (ret > 0)
1440 ret = -EIO;
1441 return ret;
1442 }
1443done:
1444 if (!PageHWPoison(hpage))
Andrea Arcangeli37c2ac72011-01-13 15:47:16 -08001445 atomic_long_add(1 << compound_trans_order(hpage), &mce_bad_pages);
Naoya Horiguchid950b952010-09-08 10:19:39 +09001446 set_page_hwpoison_huge_page(hpage);
1447 dequeue_hwpoisoned_huge_page(hpage);
1448 /* keep elevated page count for bad page */
1449 return ret;
1450}
1451
Andi Kleenfacb6012009-12-16 12:20:00 +01001452/**
1453 * soft_offline_page - Soft offline a page.
1454 * @page: page to offline
1455 * @flags: flags. Same as memory_failure().
1456 *
1457 * Returns 0 on success, otherwise negated errno.
1458 *
1459 * Soft offline a page, by migration or invalidation,
1460 * without killing anything. This is for the case when
1461 * a page is not corrupted yet (so it's still valid to access),
1462 * but has had a number of corrected errors and is better taken
1463 * out.
1464 *
1465 * The actual policy on when to do that is maintained by
1466 * user space.
1467 *
1468 * This should never impact any application or cause data loss,
1469 * however it might take some time.
1470 *
1471 * This is not a 100% solution for all memory, but tries to be
1472 * ``good enough'' for the majority of memory.
1473 */
1474int soft_offline_page(struct page *page, int flags)
1475{
1476 int ret;
1477 unsigned long pfn = page_to_pfn(page);
1478
Naoya Horiguchid950b952010-09-08 10:19:39 +09001479 if (PageHuge(page))
1480 return soft_offline_huge_page(page, flags);
1481
Andi Kleenfacb6012009-12-16 12:20:00 +01001482 ret = get_any_page(page, pfn, flags);
1483 if (ret < 0)
1484 return ret;
1485 if (ret == 0)
1486 goto done;
1487
1488 /*
1489 * Page cache page we can handle?
1490 */
1491 if (!PageLRU(page)) {
1492 /*
1493 * Try to free it.
1494 */
1495 put_page(page);
1496 shake_page(page, 1);
1497
1498 /*
1499 * Did it turn free?
1500 */
1501 ret = get_any_page(page, pfn, 0);
1502 if (ret < 0)
1503 return ret;
1504 if (ret == 0)
1505 goto done;
1506 }
1507 if (!PageLRU(page)) {
Andi Kleenfb46e732010-09-27 23:31:30 +02001508 pr_info("soft_offline: %#lx: unknown non LRU page type %lx\n",
Dean Nelsondd73e852011-10-31 17:09:04 -07001509 pfn, page->flags);
Andi Kleenfacb6012009-12-16 12:20:00 +01001510 return -EIO;
1511 }
1512
1513 lock_page(page);
1514 wait_on_page_writeback(page);
1515
1516 /*
1517 * Synchronized using the page lock with memory_failure()
1518 */
1519 if (PageHWPoison(page)) {
1520 unlock_page(page);
1521 put_page(page);
Andi Kleenfb46e732010-09-27 23:31:30 +02001522 pr_info("soft offline: %#lx page already poisoned\n", pfn);
Andi Kleenfacb6012009-12-16 12:20:00 +01001523 return -EBUSY;
1524 }
1525
1526 /*
1527 * Try to invalidate first. This should work for
1528 * non dirty unmapped page cache pages.
1529 */
1530 ret = invalidate_inode_page(page);
1531 unlock_page(page);
Andi Kleenfacb6012009-12-16 12:20:00 +01001532 /*
Andi Kleenfacb6012009-12-16 12:20:00 +01001533 * RED-PEN would be better to keep it isolated here, but we
1534 * would need to fix isolation locking first.
1535 */
Andi Kleenfacb6012009-12-16 12:20:00 +01001536 if (ret == 1) {
Konstantin Khlebnikovbd486282011-05-24 17:12:20 -07001537 put_page(page);
Andi Kleenfacb6012009-12-16 12:20:00 +01001538 ret = 0;
Andi Kleenfb46e732010-09-27 23:31:30 +02001539 pr_info("soft_offline: %#lx: invalidated\n", pfn);
Andi Kleenfacb6012009-12-16 12:20:00 +01001540 goto done;
1541 }
1542
1543 /*
1544 * Simple invalidation didn't work.
1545 * Try to migrate to a new page instead. migrate.c
1546 * handles a large number of cases for us.
1547 */
1548 ret = isolate_lru_page(page);
Konstantin Khlebnikovbd486282011-05-24 17:12:20 -07001549 /*
1550 * Drop page reference which is came from get_any_page()
1551 * successful isolate_lru_page() already took another one.
1552 */
1553 put_page(page);
Andi Kleenfacb6012009-12-16 12:20:00 +01001554 if (!ret) {
1555 LIST_HEAD(pagelist);
Minchan Kim5db8a732011-06-15 15:08:48 -07001556 inc_zone_page_state(page, NR_ISOLATED_ANON +
1557 page_is_file_cache(page));
Andi Kleenfacb6012009-12-16 12:20:00 +01001558 list_add(&page->lru, &pagelist);
Mel Gorman77f1fe62011-01-13 15:45:57 -08001559 ret = migrate_pages(&pagelist, new_page, MPOL_MF_MOVE_ALL,
Mel Gormana6bc32b2012-01-12 17:19:43 -08001560 0, MIGRATE_SYNC);
Andi Kleenfacb6012009-12-16 12:20:00 +01001561 if (ret) {
Andrea Arcangeli57fc4a52011-02-01 15:52:32 -08001562 putback_lru_pages(&pagelist);
Andi Kleenfb46e732010-09-27 23:31:30 +02001563 pr_info("soft offline: %#lx: migration failed %d, type %lx\n",
Andi Kleenfacb6012009-12-16 12:20:00 +01001564 pfn, ret, page->flags);
1565 if (ret > 0)
1566 ret = -EIO;
1567 }
1568 } else {
Andi Kleenfb46e732010-09-27 23:31:30 +02001569 pr_info("soft offline: %#lx: isolation failed: %d, page count %d, type %lx\n",
Dean Nelsondd73e852011-10-31 17:09:04 -07001570 pfn, ret, page_count(page), page->flags);
Andi Kleenfacb6012009-12-16 12:20:00 +01001571 }
1572 if (ret)
1573 return ret;
1574
1575done:
1576 atomic_long_add(1, &mce_bad_pages);
1577 SetPageHWPoison(page);
1578 /* keep elevated page count for bad page */
1579 return ret;
1580}