* [to-be-updated] mm-hugetlb-fix-a-race-between-isolating-and-freeing-page.patch removed from -mm tree
@ 2021-01-17 20:44 akpm
0 siblings, 0 replies; only message in thread
From: akpm @ 2021-01-17 20:44 UTC (permalink / raw)
To: ak, mhocko, mike.kravetz, mm-commits, n-horiguchi, songmuchun, stable
The patch titled
Subject: mm: hugetlb: fix a race between isolating and freeing page
has been removed from the -mm tree. Its filename was
mm-hugetlb-fix-a-race-between-isolating-and-freeing-page.patch
This patch was dropped because an updated version will be merged
------------------------------------------------------
From: Muchun Song <songmuchun@bytedance.com>
Subject: mm: hugetlb: fix a race between isolating and freeing page
There is a race between isolate_huge_page() and __free_huge_page().
CPU0: CPU1:
if (PageHuge(page))
put_page(page)
__free_huge_page(page)
spin_lock(&hugetlb_lock)
update_and_free_page(page)
set_compound_page_dtor(page,
NULL_COMPOUND_DTOR)
spin_unlock(&hugetlb_lock)
isolate_huge_page(page)
// trigger BUG_ON
VM_BUG_ON_PAGE(!PageHead(page), page)
spin_lock(&hugetlb_lock)
page_huge_active(page)
// trigger BUG_ON
VM_BUG_ON_PAGE(!PageHuge(page), page)
spin_unlock(&hugetlb_lock)
When we isolate a HugeTLB page on CPU0. Meanwhile, we free it to the
buddy allocator on CPU1. Then, we can trigger a BUG_ON on CPU0. Because
it is already freed to the buddy allocator.
Link: https://lkml.kernel.org/r/20210110124017.86750-6-songmuchun@bytedance.com
Fixes: c8721bbbdd36 ("mm: memory-hotplug: enable memory hotplug to handle hugepage")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/hugetlb.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/mm/hugetlb.c~mm-hugetlb-fix-a-race-between-isolating-and-freeing-page
+++ a/mm/hugetlb.c
@@ -5581,9 +5581,9 @@ bool isolate_huge_page(struct page *page
{
bool ret = true;
- VM_BUG_ON_PAGE(!PageHead(page), page);
spin_lock(&hugetlb_lock);
- if (!page_huge_active(page) || !get_page_unless_zero(page)) {
+ if (!PageHeadHuge(page) || !page_huge_active(page) ||
+ !get_page_unless_zero(page)) {
ret = false;
goto unlock;
}
_
Patches currently in -mm which might be from songmuchun@bytedance.com are
mm-hugetlb-remove-vm_bug_on_page-from-page_huge_active.patch
mm-memcontrol-optimize-per-lruvec-stats-counter-memory-usage.patch
mm-memcontrol-fix-nr_anon_thps-accounting-in-charge-moving.patch
mm-memcontrol-convert-nr_anon_thps-account-to-pages.patch
mm-memcontrol-convert-nr_file_thps-account-to-pages.patch
mm-memcontrol-convert-nr_shmem_thps-account-to-pages.patch
mm-memcontrol-convert-nr_shmem_pmdmapped-account-to-pages.patch
mm-memcontrol-convert-nr_file_pmdmapped-account-to-pages.patch
mm-memcontrol-make-the-slab-calculation-consistent.patch
mm-migrate-do-not-migrate-hugetlb-page-whose-refcount-is-one.patch
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2021-01-17 20:44 [to-be-updated] mm-hugetlb-fix-a-race-between-isolating-and-freeing-page.patch removed from -mm tree akpm
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