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h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=b7eB2Zj0HMh+W1nUIU3X2oj3xDi67z7zqFrF3NQgu6w=; b=plmojXGfkum6xDLQl1jaT//nKAgg2sPqnR//NLBZwa9twOHbR3DQvDIIWAytJ3ufcK Hj8hB/m9347Tb22wFvwKvOE3c3IbGEbwnByrbV6mek90QuVf/OMtx9Ob2TTT5+dBX5Ou R9ChaB05tDALaVSKl3eTmj2l4ECSB+wugmJTXLp5hG6AtvWctbCyKnF6igpUp9+apv0h ipfvD3PsZYz/jXzdUscxSTb7o6zZNuXv0GguQPFD5XxibVR1Rn16yoXKosWOZnu5Z0Yc Qn0t0HBBXpzPX8no6xiaD5xgOxx32pmNJqjWigoGDP/Za/y+NKb0NURNir7UMo4ZgP8b nXPg== X-Gm-Message-State: APjAAAV3WOMnzUMmeqFBl8G9U1yAFlUGNsMXiWnzboNOXZXuRaDiek7r zq0SQ6LWZftWPdsZ4zE802csxdK/bZaCJKxd86Eq2g== X-Google-Smtp-Source: APXvYqy9CZ28RW2zKXiUC9d6EbgNnSdWP2+JzbdmSoIMlTI53bhmKqSgfp9RMosERJQCBAbFi870wx+/J0sJND9jXEA= X-Received: by 2002:a63:3006:: with SMTP id w6mr9148267pgw.440.1568898551847; Thu, 19 Sep 2019 06:09:11 -0700 (PDT) MIME-Version: 1.0 References: <000000000000e669b80592ab96fc@google.com> <20190919082359.GA30545@localhost> In-Reply-To: <20190919082359.GA30545@localhost> From: Andrey Konovalov Date: Thu, 19 Sep 2019 15:09:00 +0200 Message-ID: Subject: Re: possible deadlock in tower_open To: Johan Hovold Cc: syzbot , Greg Kroah-Hartman , legousb-devel@lists.sourceforge.net, LKML , USB list , starblue@users.sourceforge.net, syzkaller-bugs Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 19, 2019 at 10:24 AM Johan Hovold wrote: > > 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) Hi Johan, You did it right, now the status is changed to "closed as dup": https://syzkaller.appspot.com/bug?extid=66935bec147fbf68d9f8 Thanks!