From 5c2a956c3eea173b2bc89f632507c0eeaebf6c4a Mon Sep 17 00:00:00 2001 From: Miaohe Lin Date: Tue, 22 Mar 2022 14:44:56 -0700 Subject: mm/mlock: fix potential imbalanced rlimit ucounts adjustment user_shm_lock forgets to set allowed to 0 when get_ucounts fails. So the later user_shm_unlock might do the extra dec_rlimit_ucounts. Fix this by resetting allowed to 0. Link: https://lkml.kernel.org/r/20220310132417.41189-1-linmiaohe@huawei.com Fixes: d7c9e99aee48 ("Reimplement RLIMIT_MEMLOCK on top of ucounts") Signed-off-by: Miaohe Lin Reviewed-by: Andrew Morton Acked-by: Hugh Dickins Cc: Herbert van den Bergh Cc: Chris Mason Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/mlock.c | 1 + 1 file changed, 1 insertion(+) (limited to 'mm/mlock.c') diff --git a/mm/mlock.c b/mm/mlock.c index 25934e7db3e1..349e2cda8c50 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -839,6 +839,7 @@ int user_shm_lock(size_t size, struct ucounts *ucounts) } if (!get_ucounts(ucounts)) { dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked); + allowed = 0; goto out; } allowed = 1; -- cgit v1.2.3