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[142.68.57.212]) by smtp.gmail.com with ESMTPSA id t13sm1726812qkm.60.2020.02.26.12.42.38 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 26 Feb 2020 12:42:38 -0800 (PST) Received: from jgg by mlx.ziepe.ca with local (Exim 4.90_1) (envelope-from ) id 1j73Vu-0007FH-8G; Wed, 26 Feb 2020 16:42:38 -0400 Date: Wed, 26 Feb 2020 16:42:38 -0400 From: Jason Gunthorpe To: syzbot Cc: chuck.lever@oracle.com, dledford@redhat.com, leon@kernel.org, linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org, netdev@vger.kernel.org, parav@mellanox.com, syzkaller-bugs@googlegroups.com, willy@infradead.org, Bernard Metzler Subject: Re: possible deadlock in cma_netdev_callback Message-ID: <20200226204238.GC31668@ziepe.ca> References: <000000000000153fac059f740693@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <000000000000153fac059f740693@google.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Feb 25, 2020 at 09:39:10PM -0800, syzbot wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: 6132c1d9 net: core: devlink.c: Hold devlink->lock from the.. > git tree: net > console output: https://syzkaller.appspot.com/x/log.txt?x=16978909e00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=3b8906eb6a7d6028 > dashboard link: https://syzkaller.appspot.com/bug?extid=55de90ab5f44172b0c90 > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12808281e00000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=134ca6fde00000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+55de90ab5f44172b0c90@syzkaller.appspotmail.com > > iwpm_register_pid: Unable to send a nlmsg (client = 2) > infiniband syz1: RDMA CMA: cma_listen_on_dev, error -98 > netlink: 'syz-executor639': attribute type 1 has an invalid length. > 8021q: adding VLAN 0 to HW filter on device bond1 > bond1: (slave gretap1): making interface the new active one > ====================================================== > WARNING: possible circular locking dependency detected > 5.6.0-rc2-syzkaller #0 Not tainted > syz-executor639/9689 is trying to acquire lock: > ffffffff8a5d2a60 (lock#3){+.+.}, at: cma_netdev_callback+0xc6/0x380 drivers/infiniband/core/cma.c:4605 > > but task is already holding lock: > ffffffff8a74da00 (rtnl_mutex){+.+.}, at: rtnl_lock net/core/rtnetlink.c:72 [inline] > ffffffff8a74da00 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x405/0xaf0 net/core/rtnetlink.c:5433 > Bernard, this is a siw bug too, it is not allowed to get RTNL in siw_create_listen() (though this is probably for silly reasons and could be fixed) It is not easy to get this into the lockdep, I'll send a different patch too Jason