The patch titled
Subject: mm: memory-failure: fix race window when trying to get hugetlb folio
has been added to the -mm mm-unstable branch. Its filename is
mm-memory-failure-fix-race-window-when-trying-to-get-hugetlb-folio.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-memory-failure-fix-race-window-when-trying-to-get-hugetlb-folio.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Subject: mm: memory-failure: fix race window when trying to get hugetlb folio
Date: Tue, 11 Jul 2023 13:50:16 +0800
page_folio() is fetched before calling get_hwpoison_hugetlb_folio()
without hugetlb_lock being held. So hugetlb page could be demoted before
get_hwpoison_hugetlb_folio() holding hugetlb_lock but after page_folio()
is fetched. So get_hwpoison_hugetlb_folio() will hold unexpected extra
refcnt of hugetlb folio while leaving demoted page un-refcnted.
Link: https://lkml.kernel.org/r/20230711055016.2286677-9-linmiaohe@xxxxxxxxxx
Fixes: 25182f05ffed ("mm,hwpoison: fix race with hugetlb page allocation")
Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Acked-by: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory-failure.c | 20 ++++++++++++++++----
1 file changed, 16 insertions(+), 4 deletions(-)
--- a/mm/memory-failure.c~mm-memory-failure-fix-race-window-when-trying-to-get-hugetlb-folio
+++ a/mm/memory-failure.c
@@ -1383,8 +1383,15 @@ static int __get_hwpoison_page(struct pa
bool hugetlb = false;
ret = get_hwpoison_hugetlb_folio(folio, &hugetlb, false);
- if (hugetlb)
- return ret;
+ if (hugetlb) {
+ /* Make sure hugetlb demotion did not happen from under us. */
+ if (folio == page_folio(page))
+ return ret;
+ if (ret > 0) {
+ folio_put(folio);
+ folio = page_folio(page);
+ }
+ }
/*
* This check prevents from calling folio_try_get() for any
@@ -1473,8 +1480,13 @@ static int __get_unpoison_page(struct pa
bool hugetlb = false;
ret = get_hwpoison_hugetlb_folio(folio, &hugetlb, true);
- if (hugetlb)
- return ret;
+ if (hugetlb) {
+ /* Make sure hugetlb demotion did not happen from under us. */
+ if (folio == page_folio(page))
+ return ret;
+ if (ret > 0)
+ folio_put(folio);
+ }
/*
* PageHWPoisonTakenOff pages are not only marked as PG_hwpoison,
_
Patches currently in -mm which might be from linmiaohe@xxxxxxxxxx are
mm-mm_initc-update-obsolete-comment-in-get_pfn_range_for_nid.patch
mm-memory-failure-fix-unexpected-return-value-in-soft_offline_page.patch
mm-memory-failure-fix-potential-page-refcnt-leak-in-memory_failure.patch
mm-memory-failure-remove-unneeded-page-state-check-in-shake_page.patch
memory-tier-use-helper-function-destroy_memory_type.patch
mm-memory-failure-remove-unneeded-inline-annotation.patch
mm-mm_initc-remove-obsolete-macro-hash_small.patch
mm-page_alloc-avoid-false-page-outside-zone-error-info.patch
memory-tier-rename-destroy_memory_type-to-put_memory_type.patch
mm-remove-obsolete-comment-above-struct-per_cpu_pages.patch
mm-memcg-minor-cleanup-for-mem_cgroup_id_max.patch
mm-memory-failure-remove-unneeded-pagehuge-check.patch
mm-memory-failure-ensure-moving-hwpoison-flag-to-the-raw-error-pages.patch
mm-memory-failure-dont-account-hwpoison_filter-filtered-pages.patch
mm-memory-failure-use-local-variable-huge-to-check-hugetlb-page.patch
mm-memory-failure-remove-unneeded-header-files.patch
mm-memory-failure-minor-cleanup-for-comments-and-codestyle.patch
mm-memory-failure-fetch-compound-head-after-extra-page-refcnt-is-held.patch
mm-memory-failure-fix-race-window-when-trying-to-get-hugetlb-folio.patch
