From: Jakub Kicinski <kuba@kernel.org>
To: Kyle Zeng <kylebot@openai.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>,
Jiri Pirko <jiri@resnulli.us>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Paolo Abeni <pabeni@redhat.com>, Simon Horman <horms@kernel.org>,
Vlad Buslov <vladbu@nvidia.com>,
Pedro Tammela <pctammela@mojatatu.com>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH net] net/sched: act_api: use mutex in tcf_idr_check_alloc
Date: Thu, 28 May 2026 18:13:19 -0700 [thread overview]
Message-ID: <20260528181319.79aeb1b2@kernel.org> (raw)
In-Reply-To: <20260526220847.28365-1-kylebot@openai.com>
On Tue, 26 May 2026 15:08:47 -0700 Kyle Zeng wrote:
> Currently, the NEWTFILTER path uses RCU to guard action idr accesses while
> the DELTFILTER path uses mutex to guard action accesses. This
> inconsistency leads to a race condition scenario, which can lead to
> erroneous operations on refcount, eventually leading to use-after-free
> situation.
> In this patch, we revert the introduction of RCU back to mutex in the
> NEWFILTER path, which is consistent with the DELFILTER path, avoiding
> the race condition.
The commit message is quite inadequate here. Looks like a
run-of-the-mill UAF so you should explain the flow / race that leads
to it properly.
Doing some extra digging with Jamal off-list we can't find the reason
why normal RCU protection wouldn't work here so maybe hold off reposting
until you hear from Jamal.
next prev parent reply other threads:[~2026-05-29 1:13 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-26 22:08 [PATCH net] net/sched: act_api: use mutex in tcf_idr_check_alloc Kyle Zeng
2026-05-27 16:31 ` Jamal Hadi Salim
2026-05-27 17:38 ` Pedro Tammela
2026-05-28 12:21 ` Victor Nogueira
2026-05-29 1:13 ` Jakub Kicinski [this message]
2026-05-29 14:13 ` Jamal Hadi Salim
2026-05-29 23:15 ` Kyle Zeng
2026-05-30 11:49 ` Jamal Hadi Salim
2026-05-31 16:09 ` Jamal Hadi Salim
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