From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Return-Path: Sender: Tejun Heo Date: Thu, 8 Feb 2018 09:40:17 -0800 From: "tj@kernel.org" To: Bart Van Assche Cc: "hch@lst.de" , "linux-block@vger.kernel.org" , "axboe@kernel.dk" Subject: Re: [PATCH v2] blk-mq: Fix race between resetting the timer and completion handling Message-ID: <20180208174017.GR695913@devbig577.frc2.facebook.com> References: <1518027251.2870.53.camel@wdc.com> <20180207200724.GD695913@devbig577.frc2.facebook.com> <1518047297.2870.80.camel@wdc.com> <1518052193.2870.90.camel@wdc.com> <20180208153940.GM695913@devbig577.frc2.facebook.com> <1518107501.3611.19.camel@wdc.com> <20180208170010.GP695913@devbig577.frc2.facebook.com> <1518109843.3611.25.camel@wdc.com> <20180208171934.GQ695913@devbig577.frc2.facebook.com> <1518111465.3611.36.camel@wdc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1518111465.3611.36.camel@wdc.com> List-ID: On Thu, Feb 08, 2018 at 05:37:46PM +0000, Bart Van Assche wrote: > On Thu, 2018-02-08 at 09:19 -0800, tj@kernel.org wrote: > > Hello, Bart. > > > > On Thu, Feb 08, 2018 at 05:10:45PM +0000, Bart Van Assche wrote: > > > I think "dereferencing a pointer" means reading the memory location that pointer points > > > at? Anyway, I think we both interpret the crash report in the same way, namely that it > > > means that scmd->device == NULL. > > > > No, what I'm trying to say is that it's is the device->host reference > > not the scmd->device reference. > > Again, I think that means that we agree about the interpretation of the crash > report. The big question here is what the next step should be to analyze this > further and/or to avoid that this crash can occur? Heh, sorry about not being clear. What I'm trying to say is that scmd->device != NULL && device->host == NULL. Or was this what you were saying all along? Thanks. -- tejun