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([2804:14d:5c54:4d67:f17:d82a:d5b8:20a]) by smtp.gmail.com with ESMTPSA id af79cd13be357-914f87017a0sm792448585a.15.2026.05.28.05.21.48 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 28 May 2026 05:21:51 -0700 (PDT) Message-ID: <0d06e367-6114-46a5-9678-2f94827e3574@mojatatu.com> Date: Thu, 28 May 2026 09:21:47 -0300 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net] net/sched: act_api: use mutex in tcf_idr_check_alloc To: Kyle Zeng , Jamal Hadi Salim , Jiri Pirko Cc: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Vlad Buslov , Pedro Tammela , netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <20260526220847.28365-1-kylebot@openai.com> Content-Language: en-US From: Victor Nogueira In-Reply-To: <20260526220847.28365-1-kylebot@openai.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 26/05/2026 19:08, 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. > > Fixes: 4b55e86736d5 ("net/sched: act_api: rely on rcu in tcf_idr_check_alloc") > Signed-off-by: Kyle Zeng Reviewed-by: Victor Nogueira