From: Florian Westphal <fw@strlen.de>
To: syzbot <syzbot+ee287f5effa60050d9ac@syzkaller.appspotmail.com>
Cc: coreteam@netfilter.org, davem@davemloft.net, edumazet@google.com,
horms@kernel.org, kadlec@netfilter.org, kuba@kernel.org,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
netfilter-devel@vger.kernel.org, pabeni@redhat.com,
pablo@netfilter.org, phil@nwl.cc,
syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [netfilter?] possible deadlock in nf_tables_dumpreset_rules
Date: Mon, 5 Jan 2026 10:15:00 +0100 [thread overview]
Message-ID: <aVuBFErrvyjKv0v5@strlen.de> (raw)
In-Reply-To: <695b76dc.050a0220.1c9965.0029.GAE@google.com>
syzbot <syzbot+ee287f5effa60050d9ac@syzkaller.appspotmail.com> wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 54e82e93ca93 Merge tag 'core_urgent_for_v6.19_rc4' of git:..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=10b1ee22580000
> kernel config: https://syzkaller.appspot.com/x/.config?x=8bfa57a8c0ab3aa8
> dashboard link: https://syzkaller.appspot.com/bug?extid=ee287f5effa60050d9ac
> compiler: gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
> userspace arch: i386
>
> Unfortunately, I don't have any reproducer for this issue yet.
>
> Downloadable assets:
> disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-54e82e93.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/c7af41d4f0f4/vmlinux-54e82e93.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/02aa2250dd4f/bzImage-54e82e93.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+ee287f5effa60050d9ac@syzkaller.appspotmail.com
>
> netlink: 48 bytes leftover after parsing attributes in process `syz.8.6539'.
> ======================================================
> WARNING: possible circular locking dependency detected
> syzkaller #0 Tainted: G L
> ------------------------------------------------------
> syz.8.6539/2008 is trying to acquire lock:
> ffff888052e32cd8 (&nft_net->commit_mutex){+.+.}-{4:4}, at: nf_tables_dumpreset_rules+0x6f/0xa0 net/netfilter/nf_tables_api.c:3913
>
> but task is already holding lock:
> ffff888025cb16f0 (nlk_cb_mutex-NETFILTER){+.+.}-{4:4}, at: __netlink_dump_start+0x150/0x990 net/netlink/af_netlink.c:2404
> which lock already depends on the new lock.
#syz dup: possible deadlock in nf_tables_dumpreset_obj
prev parent reply other threads:[~2026-01-05 9:15 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-05 8:31 [syzbot] [netfilter?] possible deadlock in nf_tables_dumpreset_rules syzbot
2026-01-05 9:15 ` Florian Westphal [this message]
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