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[85.224.241.81]) by smtp.gmail.com with ESMTPSA id l23sm1472197lje.106.2019.09.19.01.23.59 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 19 Sep 2019 01:23:59 -0700 (PDT) Received: from johan by xi.terra with local (Exim 4.92.2) (envelope-from ) id 1iArjL-0007yl-BQ; Thu, 19 Sep 2019 10:23:59 +0200 Date: Thu, 19 Sep 2019 10:23:59 +0200 From: Johan Hovold To: syzbot Cc: andreyknvl@google.com, gregkh@linuxfoundation.org, legousb-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, starblue@users.sourceforge.net, syzkaller-bugs@googlegroups.com Subject: Re: possible deadlock in tower_open Message-ID: <20190919082359.GA30545@localhost> References: <000000000000e669b80592ab96fc@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <000000000000e669b80592ab96fc@google.com> User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 16, 2019 at 06:29:12AM -0700, syzbot wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: f0df5c1b usb-fuzzer: main usb gadget fuzzer driver > git tree: https://github.com/google/kasan.git usb-fuzzer > console output: https://syzkaller.appspot.com/x/log.txt?x=13c8d14e600000 > kernel config: https://syzkaller.appspot.com/x/.config?x=5c6633fa4ed00be5 > dashboard link: https://syzkaller.appspot.com/bug?extid=66935bec147fbf68d9f8 > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > > Unfortunately, I don't have any reproducer for this crash yet. > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+66935bec147fbf68d9f8@syzkaller.appspotmail.com > > ====================================================== > WARNING: possible circular locking dependency detected > 5.3.0-rc7+ #0 Not tainted > ------------------------------------------------------ > syz-executor.1/8155 is trying to acquire lock: > 0000000086c1bdfc (open_disc_mutex){+.+.}, at: tower_open+0xce/0x9b0 > drivers/usb/misc/legousbtower.c:335 > > but task is already holding lock: > 000000000f520f73 (minor_rwsem){++++}, at: usb_open+0x23/0x270 > drivers/usb/core/file.c:39 > > which lock already depends on the new lock. This looks like a duplicate of https://lkml.kernel.org/r/000000000000d58eb90592add24e@google.com Not sure if this is the right way to report this (quoting needed?): #syz dup: possible deadlock in usb_deregister_dev (2) Johan