diff options
| author | Yichong Chen <chenyichong@uniontech.com> | 2026-07-21 11:52:07 +0800 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2026-08-06 18:57:23 -0700 |
| commit | 47f3cecd720f8f8d94ad2f206e3bfe3bc2d3d4e5 (patch) | |
| tree | a6ada2d8d803305c9bdf7e6f4f7f27212330de9b | |
| parent | 64a853c9a648be315ba92d50270791cf40ce0708 (diff) | |
hugetlb: evaluate subpool free state while locked
unlock_or_release_subpool() drops spool->lock before calling
subpool_is_free(). However, subpool_is_free() reads fields that are
updated under spool->lock, including count, used_hpages and rsv_hpages.
Keep the free-state evaluation under the same lock that protects those
fields. The reservation accounting and kfree() calls still happen after
dropping spool->lock.
Link: https://lore.kernel.org/20260721035207.1437935-1-chenyichong@uniontech.com
Signed-off-by: Yichong Chen <chenyichong@uniontech.com>
Reviewed-by: Joshua Hahn <joshua.hahnjy@gmail.com>
Reviewed-by: Jane Chu <jane.chu@oracle.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | mm/hugetlb.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 6daf831b14c5..79e5c3b3e850 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -141,12 +141,14 @@ static inline bool subpool_is_free(struct hugepage_subpool *spool) static inline void unlock_or_release_subpool(struct hugepage_subpool *spool, unsigned long irq_flags) { - spin_unlock_irqrestore(&spool->lock, irq_flags); + bool free_subpool = subpool_is_free(spool); /* If no pages are used, and no other handles to the subpool * remain, give up any reservations based on minimum size and * free the subpool */ - if (subpool_is_free(spool)) { + spin_unlock_irqrestore(&spool->lock, irq_flags); + + if (free_subpool) { if (spool->min_hpages != -1) hugetlb_acct_memory(spool->hstate, -spool->min_hpages); |