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Tue, 30 Jun 2026 12:49:56 -0700 (PDT) Received: from i4-l-hqh5357-03.ad.psu.edu ([130.203.139.71]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-8f1a7e0d5e3sm33242986d6.48.2026.06.30.12.49.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 30 Jun 2026 12:49:56 -0700 (PDT) From: Shuangpeng Bai To: netdev@vger.kernel.org Cc: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, linux-kernel@vger.kernel.org, Shuangpeng Bai , stable@vger.kernel.org Subject: [PATCH net] llc: fix SAP refcount leak in llc_ui_autobind() Date: Tue, 30 Jun 2026 15:48:56 -0400 Message-ID: <20260630194856.1036497-1-shuangpeng.kernel@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit llc_ui_autobind() opens a SAP after choosing a dynamic LSAP. llc_sap_open() returns a reference owned by the caller, and llc_sap_add_socket() takes a second reference for the socket's membership in the SAP hash tables. llc_ui_bind() drops the caller's reference after adding the socket, but llc_ui_autobind() keeps it. When the socket is closed, llc_sap_remove_socket() releases only the socket reference, leaving the SAP on llc_sap_list with sk_count == 0. This is user-visible because repeated autobind and close cycles can consume all dynamic SAP values and make later autobinds fail with -EUSERS. Drop the caller's reference after a successful autobind, matching llc_ui_bind()'s ownership model. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Signed-off-by: Shuangpeng Bai --- net/llc/af_llc.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/llc/af_llc.c b/net/llc/af_llc.c index 8ed1be1ecccc..b0447c33dbf0 100644 --- a/net/llc/af_llc.c +++ b/net/llc/af_llc.c @@ -312,6 +312,7 @@ static int llc_ui_autobind(struct socket *sock, struct sockaddr_llc *addr) /* assign new connection to its SAP */ llc_sap_add_socket(sap, sk); sock_reset_flag(sk, SOCK_ZAPPED); + llc_sap_put(sap); rc = 0; out: dev_put(dev); -- 2.43.0