From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sasha Levin Subject: [PATCH AUTOSEL 5.4 4/5] blk-throttle: fix UAF by deleteing timer in blk_throtl_exit() Date: Thu, 16 Sep 2021 22:34:48 -0400 Message-ID: <20210917023449.816713-4-sashal@kernel.org> References: <20210917023449.816713-1-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=1631846095; bh=CRf4pmmB42oIEfAQAof8E/B+8MPRPrSI6N0MyPDOqts=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RCaV+8XqqfBHz5YbUZf+Plnvr9x15+G+PBKaaxn3YtuPuKS3YIp993qw7oWy3pS84 RS1XjPlS4+Ic8kAD3Y4JkIuYLwVBoFSMPiVehofGo8LbMe90HslGe526/yhyMNG4Oo 6XsWnApbIKJO1lXapO4hj6xfs0cLZZO+8SHnNeD2FYepwedaSp9k3NY0snBD6LVQLr WFjFSPGPPUclS51MPW+m+Cc6/OSFu685ss98jEh1bpWE68Ju3FuG26H6V18r0E+05w Bb5pKCUc3+yalOK9+Dlh2HrjPRPfa01bMAM4jnY8i2vJI23jIx91WPeGABT1oi5nx/ oV3YQo2wolGgg== In-Reply-To: <20210917023449.816713-1-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 18f773e52dfb..bd870f9ae458 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[READ]); -- 2.30.2