#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/page-flags.h>
+#include <linux/kernel-page-flags.h>
#include <linux/sched.h>
#include <linux/ksm.h>
#include <linux/rmap.h>
#include <linux/pagemap.h>
#include <linux/swap.h>
#include <linux/backing-dev.h>
+#include <linux/migrate.h>
+#include <linux/page-isolation.h>
+#include <linux/suspend.h>
#include "internal.h"
int sysctl_memory_failure_early_kill __read_mostly = 0;
atomic_long_t mce_bad_pages __read_mostly = ATOMIC_LONG_INIT(0);
+#if defined(CONFIG_HWPOISON_INJECT) || defined(CONFIG_HWPOISON_INJECT_MODULE)
+
+u32 hwpoison_filter_enable = 0;
+u32 hwpoison_filter_dev_major = ~0U;
+u32 hwpoison_filter_dev_minor = ~0U;
+u64 hwpoison_filter_flags_mask;
+u64 hwpoison_filter_flags_value;
+EXPORT_SYMBOL_GPL(hwpoison_filter_enable);
+EXPORT_SYMBOL_GPL(hwpoison_filter_dev_major);
+EXPORT_SYMBOL_GPL(hwpoison_filter_dev_minor);
+EXPORT_SYMBOL_GPL(hwpoison_filter_flags_mask);
+EXPORT_SYMBOL_GPL(hwpoison_filter_flags_value);
+
+static int hwpoison_filter_dev(struct page *p)
+{
+ struct address_space *mapping;
+ dev_t dev;
+
+ if (hwpoison_filter_dev_major == ~0U &&
+ hwpoison_filter_dev_minor == ~0U)
+ return 0;
+
+ /*
+ * page_mapping() does not accept slab page
+ */
+ if (PageSlab(p))
+ return -EINVAL;
+
+ mapping = page_mapping(p);
+ if (mapping == NULL || mapping->host == NULL)
+ return -EINVAL;
+
+ dev = mapping->host->i_sb->s_dev;
+ if (hwpoison_filter_dev_major != ~0U &&
+ hwpoison_filter_dev_major != MAJOR(dev))
+ return -EINVAL;
+ if (hwpoison_filter_dev_minor != ~0U &&
+ hwpoison_filter_dev_minor != MINOR(dev))
+ return -EINVAL;
+
+ return 0;
+}
+
+static int hwpoison_filter_flags(struct page *p)
+{
+ if (!hwpoison_filter_flags_mask)
+ return 0;
+
+ if ((stable_page_flags(p) & hwpoison_filter_flags_mask) ==
+ hwpoison_filter_flags_value)
+ return 0;
+ else
+ return -EINVAL;
+}
+
+/*
+ * This allows stress tests to limit test scope to a collection of tasks
+ * by putting them under some memcg. This prevents killing unrelated/important
+ * processes such as /sbin/init. Note that the target task may share clean
+ * pages with init (eg. libc text), which is harmless. If the target task
+ * share _dirty_ pages with another task B, the test scheme must make sure B
+ * is also included in the memcg. At last, due to race conditions this filter
+ * can only guarantee that the page either belongs to the memcg tasks, or is
+ * a freed page.
+ */
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
+u64 hwpoison_filter_memcg;
+EXPORT_SYMBOL_GPL(hwpoison_filter_memcg);
+static int hwpoison_filter_task(struct page *p)
+{
+ struct mem_cgroup *mem;
+ struct cgroup_subsys_state *css;
+ unsigned long ino;
+
+ if (!hwpoison_filter_memcg)
+ return 0;
+
+ mem = try_get_mem_cgroup_from_page(p);
+ if (!mem)
+ return -EINVAL;
+
+ css = mem_cgroup_css(mem);
+ /* root_mem_cgroup has NULL dentries */
+ if (!css->cgroup->dentry)
+ return -EINVAL;
+
+ ino = css->cgroup->dentry->d_inode->i_ino;
+ css_put(css);
+
+ if (ino != hwpoison_filter_memcg)
+ return -EINVAL;
+
+ return 0;
+}
+#else
+static int hwpoison_filter_task(struct page *p) { return 0; }
+#endif
+
+int hwpoison_filter(struct page *p)
+{
+ if (!hwpoison_filter_enable)
+ return 0;
+
+ if (hwpoison_filter_dev(p))
+ return -EINVAL;
+
+ if (hwpoison_filter_flags(p))
+ return -EINVAL;
+
+ if (hwpoison_filter_task(p))
+ return -EINVAL;
+
+ return 0;
+}
+#else
+int hwpoison_filter(struct page *p)
+{
+ return 0;
+}
+#endif
+
+EXPORT_SYMBOL_GPL(hwpoison_filter);
+
/*
* Send all the processes who have the page mapped an ``action optional''
* signal.
* When a unknown page type is encountered drain as many buffers as possible
* in the hope to turn the page into a LRU or free page, which we can handle.
*/
-void shake_page(struct page *p)
+void shake_page(struct page *p, int access)
{
if (!PageSlab(p)) {
lru_add_drain_all();
if (PageLRU(p) || is_free_buddy_page(p))
return;
}
+
/*
- * Could call shrink_slab here (which would also
- * shrink other caches). Unfortunately that might
- * also access the corrupted page, which could be fatal.
+ * Only all shrink_slab here (which would also
+ * shrink other caches) if access is not potentially fatal.
*/
+ if (access) {
+ int nr;
+ do {
+ nr = shrink_slab(1000, GFP_KERNEL, 1000);
+ if (page_count(p) == 0)
+ break;
+ } while (nr > 10);
+ }
}
EXPORT_SYMBOL_GPL(shake_page);
* In case something went wrong with munmapping
* make sure the process doesn't catch the
* signal and then access the memory. Just kill it.
- * the signal handlers
*/
if (fail || tk->addr_valid == 0) {
printk(KERN_ERR
*/
enum outcome {
- FAILED, /* Error handling failed */
+ IGNORED, /* Error: cannot be handled */
+ FAILED, /* Error: handling failed */
DELAYED, /* Will be handled later */
- IGNORED, /* Error safely ignored */
RECOVERED, /* Successfully recovered */
};
static const char *action_name[] = {
+ [IGNORED] = "Ignored",
[FAILED] = "Failed",
[DELAYED] = "Delayed",
- [IGNORED] = "Ignored",
[RECOVERED] = "Recovered",
};
/*
- * Error hit kernel page.
- * Do nothing, try to be lucky and not touch this instead. For a few cases we
- * could be more sophisticated.
+ * XXX: It is possible that a page is isolated from LRU cache,
+ * and then kept in swap cache or failed to remove from page cache.
+ * The page count will stop it from being freed by unpoison.
+ * Stress tests should be aware of this memory leak problem.
*/
-static int me_kernel(struct page *p, unsigned long pfn)
+static int delete_from_lru_cache(struct page *p)
{
- return DELAYED;
+ if (!isolate_lru_page(p)) {
+ /*
+ * Clear sensible page flags, so that the buddy system won't
+ * complain when the page is unpoison-and-freed.
+ */
+ ClearPageActive(p);
+ ClearPageUnevictable(p);
+ /*
+ * drop the page count elevated by isolate_lru_page()
+ */
+ page_cache_release(p);
+ return 0;
+ }
+ return -EIO;
}
/*
- * Already poisoned page.
+ * Error hit kernel page.
+ * Do nothing, try to be lucky and not touch this instead. For a few cases we
+ * could be more sophisticated.
*/
-static int me_ignore(struct page *p, unsigned long pfn)
+static int me_kernel(struct page *p, unsigned long pfn)
{
return IGNORED;
}
}
/*
- * Free memory
- */
-static int me_free(struct page *p, unsigned long pfn)
-{
- return DELAYED;
-}
-
-/*
* Clean (or cleaned) page cache page.
*/
static int me_pagecache_clean(struct page *p, unsigned long pfn)
int ret = FAILED;
struct address_space *mapping;
+ delete_from_lru_cache(p);
+
/*
* For anonymous pages we're done the only reference left
* should be the one m_f() holds.
/* Trigger EIO in shmem: */
ClearPageUptodate(p);
- return DELAYED;
+ if (!delete_from_lru_cache(p))
+ return DELAYED;
+ else
+ return FAILED;
}
static int me_swapcache_clean(struct page *p, unsigned long pfn)
{
delete_from_swap_cache(p);
- return RECOVERED;
+ if (!delete_from_lru_cache(p))
+ return RECOVERED;
+ else
+ return FAILED;
}
/*
#define tail (1UL << PG_tail)
#define compound (1UL << PG_compound)
#define slab (1UL << PG_slab)
-#define buddy (1UL << PG_buddy)
#define reserved (1UL << PG_reserved)
static struct page_state {
char *msg;
int (*action)(struct page *p, unsigned long pfn);
} error_states[] = {
- { reserved, reserved, "reserved kernel", me_ignore },
- { buddy, buddy, "free kernel", me_free },
+ { reserved, reserved, "reserved kernel", me_kernel },
+ /*
+ * free pages are specially detected outside this table:
+ * PG_buddy pages only make a small fraction of all free pages.
+ */
/*
* Could in theory check if slab page is free or if we can drop
{ 0, 0, "unknown page state", me_unknown },
};
+#undef dirty
+#undef sc
+#undef unevict
+#undef mlock
+#undef writeback
+#undef lru
+#undef swapbacked
+#undef head
+#undef tail
+#undef compound
+#undef slab
+#undef reserved
+
static void action_result(unsigned long pfn, char *msg, int result)
{
- struct page *page = NULL;
- if (pfn_valid(pfn))
- page = pfn_to_page(pfn);
+ struct page *page = pfn_to_page(pfn);
printk(KERN_ERR "MCE %#lx: %s%s page recovery: %s\n",
pfn,
- page && PageDirty(page) ? "dirty " : "",
+ PageDirty(page) ? "dirty " : "",
msg, action_name[result]);
}
static int page_action(struct page_state *ps, struct page *p,
- unsigned long pfn, int ref)
+ unsigned long pfn)
{
int result;
int count;
result = ps->action(p, pfn);
action_result(pfn, ps->msg, result);
- count = page_count(p) - 1 - ref;
- if (count != 0)
+ count = page_count(p) - 1;
+ if (ps->action == me_swapcache_dirty && result == DELAYED)
+ count--;
+ if (count != 0) {
printk(KERN_ERR
"MCE %#lx: %s page still referenced by %d users\n",
pfn, ps->msg, count);
+ result = FAILED;
+ }
/* Could do more checks here if page looks ok */
/*
* Could adjust zone counters here to correct for the missing page.
*/
- return result == RECOVERED ? 0 : -EBUSY;
+ return (result == RECOVERED || result == DELAYED) ? 0 : -EBUSY;
}
#define N_UNMAP_TRIES 5
* Do all that is necessary to remove user space mappings. Unmap
* the pages and send SIGBUS to the processes if the data was dirty.
*/
-static void hwpoison_user_mappings(struct page *p, unsigned long pfn,
+static int hwpoison_user_mappings(struct page *p, unsigned long pfn,
int trapno)
{
enum ttu_flags ttu = TTU_UNMAP | TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS;
int i;
int kill = 1;
- if (PageReserved(p) || PageCompound(p) || PageSlab(p) || PageKsm(p))
- return;
+ if (PageReserved(p) || PageSlab(p))
+ return SWAP_SUCCESS;
/*
* This check implies we don't kill processes if their pages
* are in the swap cache early. Those are always late kills.
*/
if (!page_mapped(p))
- return;
+ return SWAP_SUCCESS;
+
+ if (PageCompound(p) || PageKsm(p))
+ return SWAP_FAIL;
if (PageSwapCache(p)) {
printk(KERN_ERR
/*
* Propagate the dirty bit from PTEs to struct page first, because we
* need this to decide if we should kill or just drop the page.
+ * XXX: the dirty test could be racy: set_page_dirty() may not always
+ * be called inside page lock (it's recommended but not enforced).
*/
mapping = page_mapping(p);
if (!PageDirty(p) && mapping && mapping_cap_writeback_dirty(mapping)) {
*/
kill_procs_ao(&tokill, !!PageDirty(p), trapno,
ret != SWAP_SUCCESS, pfn);
+
+ return ret;
}
-int __memory_failure(unsigned long pfn, int trapno, int ref)
+int __memory_failure(unsigned long pfn, int trapno, int flags)
{
- unsigned long lru_flag;
struct page_state *ps;
struct page *p;
int res;
panic("Memory failure from trap %d on page %lx", trapno, pfn);
if (!pfn_valid(pfn)) {
- action_result(pfn, "memory outside kernel control", IGNORED);
- return -EIO;
+ printk(KERN_ERR
+ "MCE %#lx: memory outside kernel control\n",
+ pfn);
+ return -ENXIO;
}
p = pfn_to_page(pfn);
if (TestSetPageHWPoison(p)) {
- action_result(pfn, "already hardware poisoned", IGNORED);
+ printk(KERN_ERR "MCE %#lx: already hardware poisoned\n", pfn);
return 0;
}
* In fact it's dangerous to directly bump up page count from 0,
* that may make page_freeze_refs()/page_unfreeze_refs() mismatch.
*/
- if (!get_page_unless_zero(compound_head(p))) {
- action_result(pfn, "free or high order kernel", IGNORED);
- return PageBuddy(compound_head(p)) ? 0 : -EBUSY;
+ if (!(flags & MF_COUNT_INCREASED) &&
+ !get_page_unless_zero(compound_head(p))) {
+ if (is_free_buddy_page(p)) {
+ action_result(pfn, "free buddy", DELAYED);
+ return 0;
+ } else {
+ action_result(pfn, "high order kernel", IGNORED);
+ return -EBUSY;
+ }
}
/*
* walked by the page reclaim code, however that's not a big loss.
*/
if (!PageLRU(p))
- lru_add_drain_all();
- lru_flag = p->flags & lru;
- if (isolate_lru_page(p)) {
+ shake_page(p, 0);
+ if (!PageLRU(p)) {
+ /*
+ * shake_page could have turned it free.
+ */
+ if (is_free_buddy_page(p)) {
+ action_result(pfn, "free buddy, 2nd try", DELAYED);
+ return 0;
+ }
action_result(pfn, "non LRU", IGNORED);
put_page(p);
return -EBUSY;
}
- page_cache_release(p);
/*
* Lock the page and wait for writeback to finish.
* and in many cases impossible, so we just avoid it here.
*/
lock_page_nosync(p);
+
+ /*
+ * unpoison always clear PG_hwpoison inside page lock
+ */
+ if (!PageHWPoison(p)) {
+ printk(KERN_ERR "MCE %#lx: just unpoisoned\n", pfn);
+ res = 0;
+ goto out;
+ }
+ if (hwpoison_filter(p)) {
+ if (TestClearPageHWPoison(p))
+ atomic_long_dec(&mce_bad_pages);
+ unlock_page(p);
+ put_page(p);
+ return 0;
+ }
+
wait_on_page_writeback(p);
/*
* Now take care of user space mappings.
+ * Abort on fail: __remove_from_page_cache() assumes unmapped page.
*/
- hwpoison_user_mappings(p, pfn, trapno);
+ if (hwpoison_user_mappings(p, pfn, trapno) != SWAP_SUCCESS) {
+ printk(KERN_ERR "MCE %#lx: cannot unmap page, give up\n", pfn);
+ res = -EBUSY;
+ goto out;
+ }
/*
* Torn down by someone else?
*/
- if ((lru_flag & lru) && !PageSwapCache(p) && p->mapping == NULL) {
+ if (PageLRU(p) && !PageSwapCache(p) && p->mapping == NULL) {
action_result(pfn, "already truncated LRU", IGNORED);
- res = 0;
+ res = -EBUSY;
goto out;
}
res = -EBUSY;
for (ps = error_states;; ps++) {
- if (((p->flags | lru_flag)& ps->mask) == ps->res) {
- res = page_action(ps, p, pfn, ref);
+ if ((p->flags & ps->mask) == ps->res) {
+ res = page_action(ps, p, pfn);
break;
}
}
{
__memory_failure(pfn, trapno, 0);
}
+
+/**
+ * unpoison_memory - Unpoison a previously poisoned page
+ * @pfn: Page number of the to be unpoisoned page
+ *
+ * Software-unpoison a page that has been poisoned by
+ * memory_failure() earlier.
+ *
+ * This is only done on the software-level, so it only works
+ * for linux injected failures, not real hardware failures
+ *
+ * Returns 0 for success, otherwise -errno.
+ */
+int unpoison_memory(unsigned long pfn)
+{
+ struct page *page;
+ struct page *p;
+ int freeit = 0;
+
+ if (!pfn_valid(pfn))
+ return -ENXIO;
+
+ p = pfn_to_page(pfn);
+ page = compound_head(p);
+
+ if (!PageHWPoison(p)) {
+ pr_debug("MCE: Page was already unpoisoned %#lx\n", pfn);
+ return 0;
+ }
+
+ if (!get_page_unless_zero(page)) {
+ if (TestClearPageHWPoison(p))
+ atomic_long_dec(&mce_bad_pages);
+ pr_debug("MCE: Software-unpoisoned free page %#lx\n", pfn);
+ return 0;
+ }
+
+ lock_page_nosync(page);
+ /*
+ * This test is racy because PG_hwpoison is set outside of page lock.
+ * That's acceptable because that won't trigger kernel panic. Instead,
+ * the PG_hwpoison page will be caught and isolated on the entrance to
+ * the free buddy page pool.
+ */
+ if (TestClearPageHWPoison(p)) {
+ pr_debug("MCE: Software-unpoisoned page %#lx\n", pfn);
+ atomic_long_dec(&mce_bad_pages);
+ freeit = 1;
+ }
+ unlock_page(page);
+
+ put_page(page);
+ if (freeit)
+ put_page(page);
+
+ return 0;
+}
+EXPORT_SYMBOL(unpoison_memory);
+
+static struct page *new_page(struct page *p, unsigned long private, int **x)
+{
+ int nid = page_to_nid(p);
+ return alloc_pages_exact_node(nid, GFP_HIGHUSER_MOVABLE, 0);
+}
+
+/*
+ * Safely get reference count of an arbitrary page.
+ * Returns 0 for a free page, -EIO for a zero refcount page
+ * that is not free, and 1 for any other page type.
+ * For 1 the page is returned with increased page count, otherwise not.
+ */
+static int get_any_page(struct page *p, unsigned long pfn, int flags)
+{
+ int ret;
+
+ if (flags & MF_COUNT_INCREASED)
+ return 1;
+
+ /*
+ * The lock_system_sleep prevents a race with memory hotplug,
+ * because the isolation assumes there's only a single user.
+ * This is a big hammer, a better would be nicer.
+ */
+ lock_system_sleep();
+
+ /*
+ * Isolate the page, so that it doesn't get reallocated if it
+ * was free.
+ */
+ set_migratetype_isolate(p);
+ if (!get_page_unless_zero(compound_head(p))) {
+ if (is_free_buddy_page(p)) {
+ pr_debug("get_any_page: %#lx free buddy page\n", pfn);
+ /* Set hwpoison bit while page is still isolated */
+ SetPageHWPoison(p);
+ ret = 0;
+ } else {
+ pr_debug("get_any_page: %#lx: unknown zero refcount page type %lx\n",
+ pfn, p->flags);
+ ret = -EIO;
+ }
+ } else {
+ /* Not a free page */
+ ret = 1;
+ }
+ unset_migratetype_isolate(p);
+ unlock_system_sleep();
+ return ret;
+}
+
+/**
+ * soft_offline_page - Soft offline a page.
+ * @page: page to offline
+ * @flags: flags. Same as memory_failure().
+ *
+ * Returns 0 on success, otherwise negated errno.
+ *
+ * Soft offline a page, by migration or invalidation,
+ * without killing anything. This is for the case when
+ * a page is not corrupted yet (so it's still valid to access),
+ * but has had a number of corrected errors and is better taken
+ * out.
+ *
+ * The actual policy on when to do that is maintained by
+ * user space.
+ *
+ * This should never impact any application or cause data loss,
+ * however it might take some time.
+ *
+ * This is not a 100% solution for all memory, but tries to be
+ * ``good enough'' for the majority of memory.
+ */
+int soft_offline_page(struct page *page, int flags)
+{
+ int ret;
+ unsigned long pfn = page_to_pfn(page);
+
+ ret = get_any_page(page, pfn, flags);
+ if (ret < 0)
+ return ret;
+ if (ret == 0)
+ goto done;
+
+ /*
+ * Page cache page we can handle?
+ */
+ if (!PageLRU(page)) {
+ /*
+ * Try to free it.
+ */
+ put_page(page);
+ shake_page(page, 1);
+
+ /*
+ * Did it turn free?
+ */
+ ret = get_any_page(page, pfn, 0);
+ if (ret < 0)
+ return ret;
+ if (ret == 0)
+ goto done;
+ }
+ if (!PageLRU(page)) {
+ pr_debug("soft_offline: %#lx: unknown non LRU page type %lx\n",
+ pfn, page->flags);
+ return -EIO;
+ }
+
+ lock_page(page);
+ wait_on_page_writeback(page);
+
+ /*
+ * Synchronized using the page lock with memory_failure()
+ */
+ if (PageHWPoison(page)) {
+ unlock_page(page);
+ put_page(page);
+ pr_debug("soft offline: %#lx page already poisoned\n", pfn);
+ return -EBUSY;
+ }
+
+ /*
+ * Try to invalidate first. This should work for
+ * non dirty unmapped page cache pages.
+ */
+ ret = invalidate_inode_page(page);
+ unlock_page(page);
+
+ /*
+ * Drop count because page migration doesn't like raised
+ * counts. The page could get re-allocated, but if it becomes
+ * LRU the isolation will just fail.
+ * RED-PEN would be better to keep it isolated here, but we
+ * would need to fix isolation locking first.
+ */
+ put_page(page);
+ if (ret == 1) {
+ ret = 0;
+ pr_debug("soft_offline: %#lx: invalidated\n", pfn);
+ goto done;
+ }
+
+ /*
+ * Simple invalidation didn't work.
+ * Try to migrate to a new page instead. migrate.c
+ * handles a large number of cases for us.
+ */
+ ret = isolate_lru_page(page);
+ if (!ret) {
+ LIST_HEAD(pagelist);
+
+ list_add(&page->lru, &pagelist);
+ ret = migrate_pages(&pagelist, new_page, MPOL_MF_MOVE_ALL, 0);
+ if (ret) {
+ pr_debug("soft offline: %#lx: migration failed %d, type %lx\n",
+ pfn, ret, page->flags);
+ if (ret > 0)
+ ret = -EIO;
+ }
+ } else {
+ pr_debug("soft offline: %#lx: isolation failed: %d, page count %d, type %lx\n",
+ pfn, ret, page_count(page), page->flags);
+ }
+ if (ret)
+ return ret;
+
+done:
+ atomic_long_add(1, &mce_bad_pages);
+ SetPageHWPoison(page);
+ /* keep elevated page count for bad page */
+ return ret;
+}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff