From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: xiao jin To: axboe@kernel.dk, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Cc: tom.leiming@gmail.com, bart.vanassche@wdc.com, stable@vger.kernel.org, yanmin.zhang@intel.com, jin.xiao@intel.com, Ming Lei Subject: [PATCH] block: blk_init_allocated_queue() set q->fq as NULL in the fail case Date: Mon, 30 Jul 2018 14:11:12 +0800 Message-Id: <1532931072-5190-1-git-send-email-jin.xiao@intel.com> List-ID: We find the memory use-after-free issue in __blk_drain_queue() on the kernel 4.14. After read the latest kernel 4.18-rc6 we think it has the same problem. Memory is allocated for q->fq in the blk_init_allocated_queue(). If the elevator init function called with error return, it will run into the fail case to free the q->fq. Then the __blk_drain_queue() uses the same memory after the free of the q->fq, it will lead to the unpredictable event. The patch is to set q->fq as NULL in the fail case of blk_init_allocated_queue(). Fixes: commit 7c94e1c157a2 ("block: introduce blk_flush_queue to drive flush machinery") Signed-off-by: xiao jin Cc: Ming Lei Cc: Bart Van Assche Cc: --- block/blk-core.c | 1 + 1 file changed, 1 insertion(+) diff --git a/block/blk-core.c b/block/blk-core.c index b888175..52635e2 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1072,6 +1072,7 @@ int blk_init_allocated_queue(struct request_queue *q) q->exit_rq_fn(q, q->fq->flush_rq); out_free_flush_queue: blk_free_flush_queue(q->fq); + q->fq = NULL; return -ENOMEM; } EXPORT_SYMBOL(blk_init_allocated_queue); -- 1.7.9.5