From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8FEF8C433EF for ; Mon, 4 Oct 2021 15:00:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 723B2611C0 for ; Mon, 4 Oct 2021 15:00:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235202AbhJDPC2 (ORCPT ); Mon, 4 Oct 2021 11:02:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57114 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234072AbhJDPCY (ORCPT ); Mon, 4 Oct 2021 11:02:24 -0400 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [IPv6:2a0a:51c0:0:12e:520::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7999FC061745; Mon, 4 Oct 2021 08:00:35 -0700 (PDT) Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1mXPS9-0006bJ-Vx; Mon, 04 Oct 2021 17:00:30 +0200 Date: Mon, 4 Oct 2021 17:00:29 +0200 From: Florian Westphal To: Jakub Kicinski Cc: syzbot , davem@davemloft.net, johannes@sipsolutions.net, linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org, netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com, Florian Westphal Subject: Re: [syzbot] INFO: task hung in reg_check_chans_work (3) Message-ID: <20211004150029.GN2935@breakpoint.cc> References: <000000000000035e6905cd5e1c91@google.com> <20211004074157.1ba82e65@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211004074157.1ba82e65@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Jakub Kicinski wrote: > netfilter... rtnl.. workqueue... let's CC Florian.. Thanks. > > HEAD commit: a4e6f95a891a Merge tag 'pinctrl-v5.15-2' of git://git.kern.. This HEAD doesn't include 7970a19b71044bf4dc2c1becc200275bdf1884d4 netfilter: nf_nat_masquerade: defer conntrack walk to work queue so, with a bit of luck this is already resolved. > > context_switch kernel/sched/core.c:4940 [inline] > > __schedule+0x940/0x26f0 kernel/sched/core.c:6287 > > schedule+0xd3/0x270 kernel/sched/core.c:6366 > > schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6425 > > __mutex_lock_common kernel/locking/mutex.c:669 [inline] > > __mutex_lock+0xa34/0x12f0 kernel/locking/mutex.c:729 > > reg_check_chans_work+0x83/0xe10 net/wireless/reg.c:2423 > > process_one_work+0x9bf/0x16b0 kernel/workqueue.c:2297 workqueue tries to rtnl_lock()... > > task:syz-executor.0 state:D stack:27152 pid:17047 ppid: 13518 flags:0x00004004 > > Call Trace: > > context_switch kernel/sched/core.c:4940 [inline] > > __schedule+0x940/0x26f0 kernel/sched/core.c:6287 > > schedule+0xd3/0x270 kernel/sched/core.c:6366 > > schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6425 > > __mutex_lock_common kernel/locking/mutex.c:669 [inline] > > __mutex_lock+0xa34/0x12f0 kernel/locking/mutex.c:729 > > rtnl_lock net/core/rtnetlink.c:72 [inline] > > rtnetlink_rcv_msg+0x3be/0xb80 net/core/rtnetlink.c:5569 ... syz-executor as well ... > > task:syz-executor.4 state:D stack:27216 pid:17052 ppid: 6665 flags:0x00004004 > > Call Trace: > > context_switch kernel/sched/core.c:4940 [inline] > > __schedule+0x940/0x26f0 kernel/sched/core.c:6287 > > schedule+0xd3/0x270 kernel/sched/core.c:6366 > > schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6425 > > __mutex_lock_common kernel/locking/mutex.c:669 [inline] > > __mutex_lock+0xa34/0x12f0 kernel/locking/mutex.c:729 > > rtnl_lock net/core/rtnetlink.c:72 [inline] > > rtnetlink_rcv_msg+0x3be/0xb80 net/core/rtnetlink.c:5569 > > netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2504 ... and another syz-executor instance ... > > __local_bh_enable_ip+0xcd/0x120 kernel/softirq.c:371 > > local_bh_enable include/linux/bottom_half.h:32 [inline] > > get_next_corpse net/netfilter/nf_conntrack_core.c:2252 [inline] > > nf_ct_iterate_cleanup+0x15a/0x450 net/netfilter/nf_conntrack_core.c:2275 > > nf_ct_iterate_cleanup_net net/netfilter/nf_conntrack_core.c:2363 [inline] > > nf_ct_iterate_cleanup_net+0x236/0x400 net/netfilter/nf_conntrack_core.c:2347 > > masq_device_event+0xae/0xe0 net/netfilter/nf_nat_masquerade.c:88 > > notifier_call_chain+0xb5/0x200 kernel/notifier.c:83 ... and rtnl is held by notifier call chain. This is no longer the case in current net head, nf_ct_iterate_cleanup() runs from workqueue without rtnl locked.