Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 5.15 20/21] mm/mlock: fix potential imbalanced rlimit ucounts adjustment | Date | Fri, 13 May 2022 16:24:02 +0200 |
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From: Miaohe Lin <linmiaohe@huawei.com>
commit 5c2a956c3eea173b2bc89f632507c0eeaebf6c4a upstream.
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 <linmiaohe@huawei.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Hugh Dickins <hughd@google.com> Cc: Herbert van den Bergh <herbert.van.den.bergh@oracle.com> Cc: Chris Mason <chris.mason@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- mm/mlock.c | 1 + 1 file changed, 1 insertion(+)
--- a/mm/mlock.c +++ b/mm/mlock.c @@ -837,6 +837,7 @@ int user_shm_lock(size_t size, struct uc } if (!get_ucounts(ucounts)) { dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked); + allowed = 0; goto out; } allowed = 1;
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