From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: Re: [PATCH] block: blk_init_allocated_queue() set q->fq as NULL in the fail case To: xiao jin , 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, Ming Lei References: <1532931072-5190-1-git-send-email-jin.xiao@intel.com> From: Jens Axboe Message-ID: <0bd7c6a3-4c55-d2f4-9b48-01f3898891b8@kernel.dk> Date: Mon, 30 Jul 2018 08:28:49 -0600 MIME-Version: 1.0 In-Reply-To: <1532931072-5190-1-git-send-email-jin.xiao@intel.com> Content-Type: text/plain; charset=utf-8 List-ID: On 7/30/18 12:11 AM, xiao jin wrote: > 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(). Applied, thanks. -- Jens Axboe