From: Naoya Horiguchi <[email protected]>
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.
Fixes: 25182f05ffed ("mm,hwpoison: fix race with hugetlb page allocation")
Reported-by: Tony Luck <[email protected]>
Signed-off-by: Naoya Horiguchi <[email protected]>
Cc: [email protected] # 5.13
---
ChangeLog v2:
- get_any_page() return -EIO when retry limit reached (by Yang Shi)
---
mm/memory-failure.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git v5.14-rc6/mm/memory-failure.c v5.14-rc6_patched/mm/memory-failure.c
index eefd823deb67..470400cc7513 100644
--- v5.14-rc6/mm/memory-failure.c
+++ v5.14-rc6_patched/mm/memory-failure.c
@@ -1146,7 +1146,7 @@ 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)) {
/*
@@ -1199,9 +1199,15 @@ static int get_any_page(struct page *p, unsigned long flags)
}
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;
}
}
--
2.25.1
On Wed, Aug 18, 2021 at 5:20 PM Naoya Horiguchi
<[email protected]> wrote:
>
> From: Naoya Horiguchi <[email protected]>
>
> 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.
>
> Fixes: 25182f05ffed ("mm,hwpoison: fix race with hugetlb page allocation")
> Reported-by: Tony Luck <[email protected]>
> Signed-off-by: Naoya Horiguchi <[email protected]>
> Cc: [email protected] # 5.13
> ---
> ChangeLog v2:
> - get_any_page() return -EIO when retry limit reached (by Yang Shi)
Thanks for taking this. The fix looks good to me. Reviewed-by: Yang
Shi <[email protected]>
> ---
> mm/memory-failure.c | 12 +++++++++---
> 1 file changed, 9 insertions(+), 3 deletions(-)
>
> diff --git v5.14-rc6/mm/memory-failure.c v5.14-rc6_patched/mm/memory-failure.c
> index eefd823deb67..470400cc7513 100644
> --- v5.14-rc6/mm/memory-failure.c
> +++ v5.14-rc6_patched/mm/memory-failure.c
> @@ -1146,7 +1146,7 @@ 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)) {
> /*
> @@ -1199,9 +1199,15 @@ static int get_any_page(struct page *p, unsigned long flags)
> }
> 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;
> }
> }
> --
> 2.25.1
>
>