#include <linux/ratelimit.h>
#include <linux/page-isolation.h>
#include <linux/pagewalk.h>
+#include <linux/shmem_fs.h>
#include "internal.h"
#include "ras/ras_event.h"
};
priv.tk.tsk = p;
+ if (!p->mm)
+ return -EFAULT;
+
mmap_read_lock(p->mm);
ret = walk_page_range(p->mm, 0, TASK_SIZE, &hwp_walk_ops,
(void *)&priv);
if (ret == 1 && priv.tk.addr)
kill_proc(&priv.tk, pfn, flags);
+ else
+ ret = 0;
mmap_read_unlock(p->mm);
- return ret ? -EFAULT : -EHWPOISON;
+ return ret > 0 ? -EHWPOISON : -EFAULT;
}
static const char *action_name[] = {
return ret;
}
+struct page_state {
+ unsigned long mask;
+ unsigned long res;
+ enum mf_action_page_type type;
+
+ /* Callback ->action() has to unlock the relevant page inside it. */
+ int (*action)(struct page_state *ps, struct page *p);
+};
+
+/*
+ * Return true if page is still referenced by others, otherwise return
+ * false.
+ *
+ * The extra_pins is true when one extra refcount is expected.
+ */
+static bool has_extra_refcount(struct page_state *ps, struct page *p,
+ bool extra_pins)
+{
+ int count = page_count(p) - 1;
+
+ if (extra_pins)
+ count -= 1;
+
+ if (count > 0) {
+ pr_err("Memory failure: %#lx: %s still referenced by %d users\n",
+ page_to_pfn(p), action_page_types[ps->type], count);
+ return true;
+ }
+
+ return false;
+}
+
/*
* 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_kernel(struct page *p, unsigned long pfn)
+static int me_kernel(struct page_state *ps, struct page *p)
{
unlock_page(p);
return MF_IGNORED;
/*
* Page in unknown state. Do nothing.
*/
-static int me_unknown(struct page *p, unsigned long pfn)
+static int me_unknown(struct page_state *ps, struct page *p)
{
- pr_err("Memory failure: %#lx: Unknown page state\n", pfn);
+ pr_err("Memory failure: %#lx: Unknown page state\n", page_to_pfn(p));
unlock_page(p);
return MF_FAILED;
}
/*
* Clean (or cleaned) page cache page.
*/
-static int me_pagecache_clean(struct page *p, unsigned long pfn)
+static int me_pagecache_clean(struct page_state *ps, struct page *p)
{
int ret;
struct address_space *mapping;
+ bool extra_pins;
delete_from_lru_cache(p);
}
/*
+ * The shmem page is kept in page cache instead of truncating
+ * so is expected to have an extra refcount after error-handling.
+ */
+ extra_pins = shmem_mapping(mapping);
+
+ /*
* Truncation is a bit tricky. Enable it per file system for now.
*
* Open: to take i_rwsem or not for this? Right now we don't.
*/
- ret = truncate_error_page(p, pfn, mapping);
+ ret = truncate_error_page(p, page_to_pfn(p), mapping);
+ if (has_extra_refcount(ps, p, extra_pins))
+ ret = MF_FAILED;
+
out:
unlock_page(p);
+
return ret;
}
* Issues: when the error hit a hole page the error is not properly
* propagated.
*/
-static int me_pagecache_dirty(struct page *p, unsigned long pfn)
+static int me_pagecache_dirty(struct page_state *ps, struct page *p)
{
struct address_space *mapping = page_mapping(p);
mapping_set_error(mapping, -EIO);
}
- return me_pagecache_clean(p, pfn);
+ return me_pagecache_clean(ps, p);
}
/*
* Clean swap cache pages can be directly isolated. A later page fault will
* bring in the known good data from disk.
*/
-static int me_swapcache_dirty(struct page *p, unsigned long pfn)
+static int me_swapcache_dirty(struct page_state *ps, struct page *p)
{
int ret;
+ bool extra_pins = false;
ClearPageDirty(p);
/* Trigger EIO in shmem: */
ret = delete_from_lru_cache(p) ? MF_FAILED : MF_DELAYED;
unlock_page(p);
+
+ if (ret == MF_DELAYED)
+ extra_pins = true;
+
+ if (has_extra_refcount(ps, p, extra_pins))
+ ret = MF_FAILED;
+
return ret;
}
-static int me_swapcache_clean(struct page *p, unsigned long pfn)
+static int me_swapcache_clean(struct page_state *ps, struct page *p)
{
int ret;
ret = delete_from_lru_cache(p) ? MF_FAILED : MF_RECOVERED;
unlock_page(p);
+
+ if (has_extra_refcount(ps, p, false))
+ ret = MF_FAILED;
+
return ret;
}
* - Error on hugepage is contained in hugepage unit (not in raw page unit.)
* To narrow down kill region to one page, we need to break up pmd.
*/
-static int me_huge_page(struct page *p, unsigned long pfn)
+static int me_huge_page(struct page_state *ps, struct page *p)
{
int res;
struct page *hpage = compound_head(p);
struct address_space *mapping;
+ bool extra_pins = false;
if (!PageHuge(hpage))
return MF_DELAYED;
mapping = page_mapping(hpage);
if (mapping) {
- res = truncate_error_page(hpage, pfn, mapping);
+ res = truncate_error_page(hpage, page_to_pfn(p), mapping);
+ /* The page is kept in page cache. */
+ extra_pins = true;
unlock_page(hpage);
} else {
res = MF_FAILED;
}
}
+ if (has_extra_refcount(ps, p, extra_pins))
+ res = MF_FAILED;
+
return res;
}
#define slab (1UL << PG_slab)
#define reserved (1UL << PG_reserved)
-static struct page_state {
- unsigned long mask;
- unsigned long res;
- enum mf_action_page_type type;
-
- /* Callback ->action() has to unlock the relevant page inside it. */
- int (*action)(struct page *p, unsigned long pfn);
-} error_states[] = {
+static struct page_state error_states[] = {
{ reserved, reserved, MF_MSG_KERNEL, me_kernel },
/*
* free pages are specially detected outside this table:
unsigned long pfn)
{
int result;
- int count;
/* page p should be unlocked after returning from ps->action(). */
- result = ps->action(p, pfn);
+ result = ps->action(ps, p);
- count = page_count(p) - 1;
- if (ps->action == me_swapcache_dirty && result == MF_DELAYED)
- count--;
- if (count > 0) {
- pr_err("Memory failure: %#lx: %s still referenced by %d users\n",
- pfn, action_page_types[ps->type], count);
- result = MF_FAILED;
- }
action_result(pfn, ps->type, result);
/* Could do more checks here if page looks ok */
if (!HWPoisonHandlable(head))
return -EBUSY;
- if (PageTransHuge(head)) {
- /*
- * Non anonymous thp exists only in allocation/free time. We
- * can't handle such a case correctly, so let's give it up.
- * This should be better than triggering BUG_ON when kernel
- * tries to touch the "partially handled" page.
- */
- if (!PageAnon(head)) {
- pr_err("Memory failure: %#lx: non anonymous thp\n",
- page_to_pfn(page));
- return 0;
- }
- }
-
if (get_page_unless_zero(head)) {
if (head == compound_head(page))
return 1;
}
out:
if (ret == -EIO)
- dump_page(p, "hwpoison: unhandlable page");
+ pr_err("Memory failure: %#lx: unhandlable page.\n", page_to_pfn(p));
return ret;
}
static int try_to_split_thp_page(struct page *page, const char *msg)
{
lock_page(page);
- if (!PageAnon(page) || unlikely(split_huge_page(page))) {
+ if (unlikely(split_huge_page(page))) {
unsigned long pfn = page_to_pfn(page);
unlock_page(page);
- if (!PageAnon(page))
- pr_info("%s: %#lx: non anonymous thp\n", msg, pfn);
- else
- pr_info("%s: %#lx: thp split failed\n", msg, pfn);
+ pr_info("%s: %#lx: thp split failed\n", msg, pfn);
put_page(page);
return -EBUSY;
}
return 0;
}
-static int memory_failure_hugetlb(unsigned long pfn, int flags)
+/*
+ * Called from hugetlb code with hugetlb_lock held.
+ *
+ * Return values:
+ * 0 - free hugepage
+ * 1 - in-use hugepage
+ * 2 - not a hugepage
+ * -EBUSY - the hugepage is busy (try to retry)
+ * -EHWPOISON - the hugepage is already hwpoisoned
+ */
+int __get_huge_page_for_hwpoison(unsigned long pfn, int flags)
+{
+ struct page *page = pfn_to_page(pfn);
+ struct page *head = compound_head(page);
+ int ret = 2; /* fallback to normal page handling */
+ bool count_increased = false;
+
+ if (!PageHeadHuge(head))
+ goto out;
+
+ if (flags & MF_COUNT_INCREASED) {
+ ret = 1;
+ count_increased = true;
+ } else if (HPageFreed(head) || HPageMigratable(head)) {
+ ret = get_page_unless_zero(head);
+ if (ret)
+ count_increased = true;
+ } else {
+ ret = -EBUSY;
+ goto out;
+ }
+
+ if (TestSetPageHWPoison(head)) {
+ ret = -EHWPOISON;
+ goto out;
+ }
+
+ return ret;
+out:
+ if (count_increased)
+ put_page(head);
+ return ret;
+}
+
+#ifdef CONFIG_HUGETLB_PAGE
+/*
+ * Taking refcount of hugetlb pages needs extra care about race conditions
+ * with basic operations like hugepage allocation/free/demotion.
+ * So some of prechecks for hwpoison (pinning, and testing/setting
+ * PageHWPoison) should be done in single hugetlb_lock range.
+ */
+static int try_memory_failure_hugetlb(unsigned long pfn, int flags, int *hugetlb)
{
- struct page *p = pfn_to_page(pfn);
- struct page *head = compound_head(p);
int res;
+ struct page *p = pfn_to_page(pfn);
+ struct page *head;
unsigned long page_flags;
+ bool retry = true;
- if (TestSetPageHWPoison(head)) {
- pr_err("Memory failure: %#lx: already hardware poisoned\n",
- pfn);
- res = -EHWPOISON;
- if (flags & MF_ACTION_REQUIRED)
+ *hugetlb = 1;
+retry:
+ res = get_huge_page_for_hwpoison(pfn, flags);
+ if (res == 2) { /* fallback to normal page handling */
+ *hugetlb = 0;
+ return 0;
+ } else if (res == -EHWPOISON) {
+ pr_err("Memory failure: %#lx: already hardware poisoned\n", pfn);
+ if (flags & MF_ACTION_REQUIRED) {
+ head = compound_head(p);
res = kill_accessing_process(current, page_to_pfn(head), flags);
+ }
+ return res;
+ } else if (res == -EBUSY) {
+ if (retry) {
+ retry = false;
+ goto retry;
+ }
+ action_result(pfn, MF_MSG_UNKNOWN, MF_IGNORED);
return res;
}
- num_poisoned_pages_inc();
+ head = compound_head(p);
+ lock_page(head);
- if (!(flags & MF_COUNT_INCREASED)) {
- res = get_hwpoison_page(p, flags);
- if (!res) {
- /*
- * Check "filter hit" and "race with other subpage."
- */
- lock_page(head);
- if (PageHWPoison(head)) {
- if ((hwpoison_filter(p) && TestClearPageHWPoison(p))
- || (p != head && TestSetPageHWPoison(head))) {
- num_poisoned_pages_dec();
- unlock_page(head);
- return 0;
- }
- }
- unlock_page(head);
- res = MF_FAILED;
- if (__page_handle_poison(p)) {
- page_ref_inc(p);
- res = MF_RECOVERED;
- }
- action_result(pfn, MF_MSG_FREE_HUGE, res);
- return res == MF_RECOVERED ? 0 : -EBUSY;
- } else if (res < 0) {
- action_result(pfn, MF_MSG_UNKNOWN, MF_IGNORED);
- return -EBUSY;
- }
+ if (hwpoison_filter(p)) {
+ ClearPageHWPoison(head);
+ res = -EOPNOTSUPP;
+ goto out;
}
- lock_page(head);
- page_flags = head->flags;
+ num_poisoned_pages_inc();
- if (!PageHWPoison(head)) {
- pr_err("Memory failure: %#lx: just unpoisoned\n", pfn);
- num_poisoned_pages_dec();
+ /*
+ * Handling free hugepage. The possible race with hugepage allocation
+ * or demotion can be prevented by PageHWPoison flag.
+ */
+ if (res == 0) {
unlock_page(head);
- put_page(head);
- return 0;
+ res = MF_FAILED;
+ if (__page_handle_poison(p)) {
+ page_ref_inc(p);
+ res = MF_RECOVERED;
+ }
+ action_result(pfn, MF_MSG_FREE_HUGE, res);
+ return res == MF_RECOVERED ? 0 : -EBUSY;
}
+ page_flags = head->flags;
+
/*
* TODO: hwpoison for pud-sized hugetlb doesn't work right now, so
* simply disable it. In order to make it work properly, we need
unlock_page(head);
return res;
}
+#else
+static inline int try_memory_failure_hugetlb(unsigned long pfn, int flags, int *hugetlb)
+{
+ return 0;
+}
+#endif
static int memory_failure_dev_pagemap(unsigned long pfn, int flags,
struct dev_pagemap *pgmap)
goto out;
if (hwpoison_filter(page)) {
- rc = 0;
+ rc = -EOPNOTSUPP;
goto unlock;
}
return rc;
}
+static DEFINE_MUTEX(mf_mutex);
+
/**
* memory_failure - Handle memory failure of a page.
* @pfn: Page Number of the corrupted page
*
* Must run in process context (e.g. a work queue) with interrupts
* enabled and no spinlocks hold.
+ *
+ * Return: 0 for successfully handled the memory error,
+ * -EOPNOTSUPP for memory_filter() filtered the error event,
+ * < 0(except -EOPNOTSUPP) on failure.
*/
int memory_failure(unsigned long pfn, int flags)
{
int res = 0;
unsigned long page_flags;
bool retry = true;
- static DEFINE_MUTEX(mf_mutex);
+ int hugetlb = 0;
if (!sysctl_memory_failure_recovery)
panic("Memory failure on page %lx", pfn);
mutex_lock(&mf_mutex);
try_again:
- if (PageHuge(p)) {
- res = memory_failure_hugetlb(pfn, flags);
+ res = try_memory_failure_hugetlb(pfn, flags, &hugetlb);
+ if (hugetlb)
goto unlock_mutex;
- }
if (TestSetPageHWPoison(p)) {
pr_err("Memory failure: %#lx: already hardware poisoned\n",
}
if (PageTransHuge(hpage)) {
+ /*
+ * The flag must be set after the refcount is bumped
+ * otherwise it may race with THP split.
+ * And the flag can't be set in get_hwpoison_page() since
+ * it is called by soft offline too and it is just called
+ * for !MF_COUNT_INCREASE. So here seems to be the best
+ * place.
+ *
+ * Don't need care about the above error handling paths for
+ * get_hwpoison_page() since they handle either free page
+ * or unhandlable page. The refcount is bumped iff the
+ * page is a valid handlable page.
+ */
+ SetPageHasHWPoisoned(hpage);
if (try_to_split_thp_page(p, "Memory Failure") < 0) {
action_result(pfn, MF_MSG_UNSPLIT_THP, MF_IGNORED);
res = -EBUSY;
*/
page_flags = p->flags;
- /*
- * unpoison always clear PG_hwpoison inside page lock
- */
- if (!PageHWPoison(p)) {
- pr_err("Memory failure: %#lx: just unpoisoned\n", pfn);
- num_poisoned_pages_dec();
- unlock_page(p);
- put_page(p);
- goto unlock_mutex;
- }
if (hwpoison_filter(p)) {
if (TestClearPageHWPoison(p))
num_poisoned_pages_dec();
unlock_page(p);
put_page(p);
+ res = -EOPNOTSUPP;
goto unlock_mutex;
}
struct page *page;
struct page *p;
int freeit = 0;
+ int ret = 0;
unsigned long flags = 0;
static DEFINE_RATELIMIT_STATE(unpoison_rs, DEFAULT_RATELIMIT_INTERVAL,
DEFAULT_RATELIMIT_BURST);
p = pfn_to_page(pfn);
page = compound_head(p);
+ mutex_lock(&mf_mutex);
+
if (!PageHWPoison(p)) {
unpoison_pr_info("Unpoison: Page was already unpoisoned %#lx\n",
pfn, &unpoison_rs);
- return 0;
+ goto unlock_mutex;
}
if (page_count(page) > 1) {
unpoison_pr_info("Unpoison: Someone grabs the hwpoison page %#lx\n",
pfn, &unpoison_rs);
- return 0;
+ goto unlock_mutex;
}
if (page_mapped(page)) {
unpoison_pr_info("Unpoison: Someone maps the hwpoison page %#lx\n",
pfn, &unpoison_rs);
- return 0;
+ goto unlock_mutex;
}
if (page_mapping(page)) {
unpoison_pr_info("Unpoison: the hwpoison page has non-NULL mapping %#lx\n",
pfn, &unpoison_rs);
- return 0;
- }
-
- /*
- * unpoison_memory() can encounter thp only when the thp is being
- * worked by memory_failure() and the page lock is not held yet.
- * In such case, we yield to memory_failure() and make unpoison fail.
- */
- if (!PageHuge(page) && PageTransHuge(page)) {
- unpoison_pr_info("Unpoison: Memory failure is now running on %#lx\n",
- pfn, &unpoison_rs);
- return 0;
+ goto unlock_mutex;
}
if (!get_hwpoison_page(p, flags)) {
num_poisoned_pages_dec();
unpoison_pr_info("Unpoison: Software-unpoisoned free page %#lx\n",
pfn, &unpoison_rs);
- return 0;
+ goto unlock_mutex;
}
- lock_page(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(page)) {
unpoison_pr_info("Unpoison: Software-unpoisoned page %#lx\n",
pfn, &unpoison_rs);
num_poisoned_pages_dec();
freeit = 1;
}
- unlock_page(page);
put_page(page);
if (freeit && !(pfn == my_zero_pfn(0) && page_count(p) == 1))
put_page(page);
- return 0;
+unlock_mutex:
+ mutex_unlock(&mf_mutex);
+ return ret;
}
EXPORT_SYMBOL(unpoison_memory);
return -EIO;
}
+ mutex_lock(&mf_mutex);
+
if (PageHWPoison(page)) {
pr_info("%s: %#lx page already poisoned\n", __func__, pfn);
put_ref_page(ref_page);
+ mutex_unlock(&mf_mutex);
return 0;
}
} else if (ret == 0) {
if (soft_offline_free_page(page) && try_again) {
try_again = false;
+ flags &= ~MF_COUNT_INCREASED;
goto retry;
}
}
+ mutex_unlock(&mf_mutex);
+
return ret;
}
projects / platform / kernel / linux-rpi.git / blobdiff