[PATCH 5.13 122/127] mm/hwpoison: retry with shake_page() for unhandlable pages

Sasha Levin
2021-08-24T17:04:37Z

From: Naoya Horiguchi <naoya.horiguchi@nec.com>

[ Upstream commit fcc00621d88b274b5dffd8daeea71d0e4c28b84e ]

HWPoisonHandlable() sometimes returns false for typical user pages due
to races with average memory events like transfers over LRU lists. This
causes failures in hwpoison handling.

There's retry code for such a case but does not work because the retry
loop reaches the retry limit too quickly before the page settles down to
handlable state. Let get_any_page() call shake_page() to fix it.

[naoya.horiguchi@nec.com: get_any_page(): return -EIO when retry limit reached]
Link: https://lkml.kernel.org/r/20210819001958.2365157-1-naoya.horiguchi@linux.dev

Link: https://lkml.kernel.org/r/20210817053703.2267588-1-naoya.horiguchi@linux.dev
Fixes: 25182f05ffed ("mm,hwpoison: fix race with hugetlb page allocation")
Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Reported-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: <stable@vger.kernel.org> [5.13+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
mm/memory-failure.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 18e83150194a..624763fdecc5 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -990,7 +990,7 @@ static int __get_hwpoison_page(struct page *page)
* unexpected races caused by taking a page refcount.
*/
if (!HWPoisonHandlable(head))
- return 0;
+ return -EBUSY;

if (PageTransHuge(head)) {
/*
@@ -1043,9 +1043,15 @@ try_again:
}
goto out;
} else if (ret == -EBUSY) {
- /* We raced with freeing huge page to buddy, retry. */
- if (pass++ < 3)
+ /*
+ * We raced with (possibly temporary) unhandlable
+ * page, retry.
+ */
+ if (pass++ < 3) {
+ shake_page(p, 1);
goto try_again;
+ }
+ ret = -EIO;
goto out;
}
}
--
2.30.2