From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9A24C6453 for ; Tue, 22 Mar 2022 21:44:57 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 65988C340EC; Tue, 22 Mar 2022 21:44:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1647985497; bh=xpb+C+JgfC5R4O8FqnsK5U6W1BFO1h90Du/JBYTules=; h=Date:To:From:In-Reply-To:Subject:From; b=RiFbCSUvOoTtpC/WBF8XprLOMs01Q5mjp8Rlx7EuMaXF2/rTq+WJaAHAT4pxbHSJA fqinLT2WCaMWNkx2E26MQFTE3qNaDVPtl7ykLhmwQPGrXbayUcS15yqA82TIhMba2j b9WWFRaYNnfMutq/K0F0dYXU9Rv9PJPQ9BKdJQwM= Date: Tue, 22 Mar 2022 14:44:56 -0700 To: hughd@google.com,herbert.van.den.bergh@oracle.com,chris.mason@oracle.com,linmiaohe@huawei.com,akpm@linux-foundation.org,patches@lists.linux.dev,linux-mm@kvack.org,mm-commits@vger.kernel.org,torvalds@linux-foundation.org,akpm@linux-foundation.org From: Andrew Morton In-Reply-To: <20220322143803.04a5e59a07e48284f196a2f9@linux-foundation.org> Subject: [patch 127/227] mm/mlock: fix potential imbalanced rlimit ucounts adjustment Message-Id: <20220322214457.65988C340EC@smtp.kernel.org> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: From: Miaohe Lin 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 --- mm/mlock.c | 1 + 1 file changed, 1 insertion(+) --- a/mm/mlock.c~mm-mlock-fix-potential-imbalanced-rlimit-ucounts-adjustment +++ a/mm/mlock.c @@ -839,6 +839,7 @@ 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; _