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[157.230.128.187]) by smtp.gmail.com with ESMTPSA id g11sm86161pjs.17.2020.04.20.11.46.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 20 Apr 2020 11:46:07 -0700 (PDT) Received: by 42.do-not-panic.com (Postfix, from userid 1000) id 2E8454028E; Mon, 20 Apr 2020 18:46:07 +0000 (UTC) Date: Mon, 20 Apr 2020 18:46:07 +0000 From: Luis Chamberlain To: Bart Van Assche Cc: axboe@kernel.dk, viro@zeniv.linux.org.uk, gregkh@linuxfoundation.org, rostedt@goodmis.org, mingo@redhat.com, jack@suse.cz, ming.lei@redhat.com, nstange@suse.de, akpm@linux-foundation.org, mhocko@suse.com, yukuai3@huawei.com, linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Omar Sandoval , Hannes Reinecke , Michal Hocko , syzbot+603294af2d01acfdd6da@syzkaller.appspotmail.com Subject: Re: [PATCH v2 03/10] blktrace: fix debugfs use after free Message-ID: <20200420184607.GL11244@42.do-not-panic.com> References: <20200419194529.4872-1-mcgrof@kernel.org> <20200419194529.4872-4-mcgrof@kernel.org> <91c82e6a-24ce-0b7d-e6e4-e8aa89f3fb79@acm.org> <20200420000436.GI11244@42.do-not-panic.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Sun, Apr 19, 2020 at 05:38:59PM -0700, Bart Van Assche wrote: > On 4/19/20 5:04 PM, Luis Chamberlain wrote: > > > Independent of what the purpose of the above code is, can that code be > > > rewritten such that it does not depend on the details of how names are > > > assigned to disks and partitions? Would disk_get_part() be useful here? > > > > I did try, but couldn't figure out a way. I'll keep looking but likewise > > let me know if you find a way. > > How about making blk_trace_setup() pass the result of the following > expression as an additional argument to blk_trace_setup(): > > bdev != bdev->bd_contains > > I think that is a widely used approach to verify after a block device has > been opened whether or not 'bdev' refers to a partition (bdev != > bdev->bd_contains means that 'bdev' represents a partition). Sweet, that should simplify this considerbly, thanks! Luis