From: Sasha Levin Subject: [PATCH AUTOSEL 4.14 2/2] blk-throttle: fix UAF by deleteing timer in blk_throtl_exit() Date: Thu, 16 Sep 2021 22:35:04 -0400 Message-ID: <20210917023504.816909-2-sashal@kernel.org> References: <20210917023504.816909-1-sashal@kernel.org> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1631846107; bh=3FZ4OhyV04fwq5QQvsGXb9bwYzoXuVANBmyw28fIJXs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YxjsRBgbeiuHnZF8/b4VZGQKe1niDffgSMryKcWhc9a9vBe7CPfvI0gtjNLDIEiTj avEjZWli95XnRPNt91usxYXAglQxCl7w51agPdxDCTUnuwhAkN92J2dnIMh9wiOUx9 KYSfddT4b4WcUvL0/tcpSalwAyvSiZcPQi+dIyBoHoGKxOfPmTxWNZE8T3ZLWmmlmC X0NzrWGpC5mMS1IZcr8mcv08P6+sV9s0HVz+Imph2N9BMrcGJz1wAcv5XNzijzWUcU IKx1BkEDg6IAEdntDdvChCfEq/0J/UvmGbh0vsLpK43pXK67jwqJDgGJK/vV4/icUG dlSZEPPgc0Rcw== In-Reply-To: <20210917023504.816909-1-sashal@kernel.org> List-ID: Content-Type: text/plain; charset="us-ascii" To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Li Jinlin , Jens Axboe , Sasha Levin , tj@kernel.org, cgroups@vger.kernel.org, linux-block@vger.kernel.org From: Li Jinlin [ Upstream commit 884f0e84f1e3195b801319c8ec3d5774e9bf2710 ] The pending timer has been set up in blk_throtl_init(). However, the timer is not deleted in blk_throtl_exit(). This means that the timer handler may still be running after freeing the timer, which would result in a use-after-free. Fix by calling del_timer_sync() to delete the timer in blk_throtl_exit(). Signed-off-by: Li Jinlin Link: https://lore.kernel.org/r/20210907121242.2885564-1-lijinlin3@huawei.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- block/blk-throttle.c | 1 + 1 file changed, 1 insertion(+) diff --git a/block/blk-throttle.c b/block/blk-throttle.c index a8cd7b3d9647..fcbbe2e45a2b 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -2414,6 +2414,7 @@ int blk_throtl_init(struct request_queue *q) void blk_throtl_exit(struct request_queue *q) { BUG_ON(!q->td); + del_timer_sync(&q->td->service_queue.pending_timer); throtl_shutdown_wq(q); blkcg_deactivate_policy(q, &blkcg_policy_throtl); free_percpu(q->td->latency_buckets); -- 2.30.2