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[157.230.128.187]) by smtp.gmail.com with ESMTPSA id b13sm6005334pfo.67.2020.04.15.22.25.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Apr 2020 22:25:25 -0700 (PDT) Received: by 42.do-not-panic.com (Postfix, from userid 1000) id C8C0340277; Thu, 16 Apr 2020 05:25:24 +0000 (UTC) Date: Thu, 16 Apr 2020 05:25:24 +0000 From: Luis Chamberlain To: Ming Lei Cc: axboe@kernel.dk, viro@zeniv.linux.org.uk, bvanassche@acm.org, gregkh@linuxfoundation.org, rostedt@goodmis.org, mingo@redhat.com, jack@suse.cz, 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 2/5] blktrace: fix debugfs use after free Message-ID: <20200416052524.GH11244@42.do-not-panic.com> References: <20200414041902.16769-1-mcgrof@kernel.org> <20200414041902.16769-3-mcgrof@kernel.org> <20200416021036.GA2717677@T590> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200416021036.GA2717677@T590> 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 Thu, Apr 16, 2020 at 10:10:36AM +0800, Ming Lei wrote: > In theory, multiple partitions can be traced concurrently, but looks > it never works, so it won't cause trouble for multiple partition trace. > > One userspace visible change is that blktrace debugfs dir name is switched > to disk name from partition name in case of partition trace, will it > break some utilities? How is this possible, its not clear to me, we go from: - q->debugfs_dir = debugfs_create_dir(kobject_name(q->kobj.parent), - blk_debugfs_root); To this: + q->debugfs_dir = debugfs_create_dir(kobject_name(q->kobj.parent), + blk_debugfs_root); Maybe I am overlooking something. Luis