From: Florian Westphal <fw@strlen.de>
To: Tristan Madani <tristmd@gmail.com>
Cc: pablo@netfilter.org, phil@nwl.cc,
netfilter-devel@vger.kernel.org, netdev@vger.kernel.org,
stable@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/2] netfilter: ip_tables: guard ipt_unregister_table_pre_exit against NULL ops
Date: Fri, 1 May 2026 00:16:15 +0200 [thread overview]
Message-ID: <afPUr2oksLlaMcOj@strlen.de> (raw)
In-Reply-To: <177758578919.118018.11758358602621428742@gmail.com>
Tristan Madani <tristmd@gmail.com> wrote:
> Florian Westphal <fw@strlen.de> wrote:
> > Is there a reproducer for this bug?
>
> Syzkaller hit it under failslab. The race is between the lazy
> init path in ipt_register_table() and cleanup_net(). The table
> becomes visible via xt_register_table() before ops is assigned,
> so pre_exit can find it with NULL ops.
If we have races between a thread calling ipt_register_table and
the netns cleanup path there is nothing we could ever do to fix it:
we are tearing down a live network namespace.
Something else must be going on.
next prev parent reply other threads:[~2026-04-30 22:16 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-29 17:56 [PATCH 0/2] netfilter: fix NULL ops race in iptable lazy init Tristan Madani
2026-04-29 17:56 ` [PATCH 1/2] netfilter: ip_tables: allocate hook ops before making table visible Tristan Madani
2026-04-29 17:56 ` [PATCH 2/2] netfilter: ip6_tables: " Tristan Madani
2026-04-29 18:17 ` [PATCH 0/2] netfilter: fix NULL ops race in iptable lazy init Phil Sutter
2026-04-29 21:03 ` Tristan Madani
2026-04-29 23:18 ` [PATCH v2 0/2] netfilter: fix NULL ops dereference " Tristan Madani
2026-04-29 23:19 ` [PATCH v2 1/2] netfilter: ip_tables: guard ipt_unregister_table_pre_exit against NULL ops Tristan Madani
2026-04-30 13:27 ` Florian Westphal
2026-04-30 21:49 ` Tristan Madani
2026-04-30 22:16 ` Florian Westphal [this message]
2026-05-01 20:41 ` Tristan Madani
2026-05-01 22:00 ` Florian Westphal
2026-04-29 23:19 ` [PATCH v2 2/2] netfilter: ip6_tables: guard ip6t_unregister_table_pre_exit " Tristan Madani
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