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[118.158.218.50]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2a0e96df1c9sm98306795ad.39.2025.12.17.04.47.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 17 Dec 2025 04:47:50 -0800 (PST) From: Qianchang Zhao To: linux-nfc@lists.01.org Cc: Krzysztof Kozlowski , Paolo Abeni , Jakub Kicinski , "David S. Miller" , Eric Dumazet , Simon Horman , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Qianchang Zhao Subject: [PATCH v2 1/2] nfc: llcp: avoid double release/put on LLCP_CLOSED in nfc_llcp_recv_disc() Date: Wed, 17 Dec 2025 21:46:58 +0900 Message-Id: <20251217124659.19274-2-pioooooooooip@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20251217124659.19274-1-pioooooooooip@gmail.com> References: <20251217124659.19274-1-pioooooooooip@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" nfc_llcp_sock_get() takes a reference on the LLCP socket via sock_hold(). In nfc_llcp_recv_disc(), when the socket is already in LLCP_CLOSED state, t= he code used to perform release_sock() and nfc_llcp_sock_put() in the CLOSED b= ranch but then continued execution and later performed the same cleanup again on = the common exit path. This results in refcount imbalance (double put) and unbal= anced lock release. Remove the redundant CLOSED-branch cleanup so that release_sock() and nfc_llcp_sock_put() are performed exactly once via the common exit path, wh= ile keeping the existing DM_DISC reply behavior. Fixes: d646960f7986fefb460a2b062d5ccc8ccfeacc3a ("NFC: Initial LLCP support= ") Cc: stable@vger.kernel.org Signed-off-by: Qianchang Zhao --- net/nfc/llcp_core.c | 5 ----- 1 file changed, 5 deletions(-) diff --git a/net/nfc/llcp_core.c b/net/nfc/llcp_core.c index beeb3b4d2..ed37604ed 100644 --- a/net/nfc/llcp_core.c +++ b/net/nfc/llcp_core.c @@ -1177,11 +1177,6 @@ static void nfc_llcp_recv_disc(struct nfc_llcp_local= *local, =20 nfc_llcp_socket_purge(llcp_sock); =20 - if (sk->sk_state =3D=3D LLCP_CLOSED) { - release_sock(sk); - nfc_llcp_sock_put(llcp_sock); - } - if (sk->sk_state =3D=3D LLCP_CONNECTED) { nfc_put_device(local->dev); sk->sk_state =3D LLCP_CLOSED; --=20 2.34.1 From nobody Sun Feb 8 11:25:52 2026 Received: from mail-pl1-f172.google.com (mail-pl1-f172.google.com [209.85.214.172]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3915834DB79 for ; Wed, 17 Dec 2025 12:48:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; 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[118.158.218.50]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2a0e96df1c9sm98306795ad.39.2025.12.17.04.47.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 17 Dec 2025 04:47:59 -0800 (PST) From: Qianchang Zhao To: linux-nfc@lists.01.org Cc: Krzysztof Kozlowski , Paolo Abeni , Jakub Kicinski , "David S. Miller" , Eric Dumazet , Simon Horman , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Qianchang Zhao Subject: [PATCH v2 2/2] nfc: llcp: stop processing on LLCP_CLOSED in nfc_llcp_recv_hdlc() Date: Wed, 17 Dec 2025 21:46:59 +0900 Message-Id: <20251217124659.19274-3-pioooooooooip@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20251217124659.19274-1-pioooooooooip@gmail.com> References: <20251217124659.19274-1-pioooooooooip@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" nfc_llcp_sock_get() takes a reference on the LLCP socket via sock_hold(). In nfc_llcp_recv_hdlc(), the LLCP_CLOSED branch releases the socket lock and drops the reference, but the function continues to operate on llcp_sock/sk = and later runs release_sock() and nfc_llcp_sock_put() again on the common exit = path. Return immediately after the CLOSED cleanup to avoid refcount/lock imbalanc= e and to avoid using the socket after dropping the reference. Fixes: d646960f7986fefb460a2b062d5ccc8ccfeacc3a ("NFC: Initial LLCP support= ") Cc: stable@vger.kernel.org Signed-off-by: Qianchang Zhao --- net/nfc/llcp_core.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/nfc/llcp_core.c b/net/nfc/llcp_core.c index ed37604ed..f6c1d79f9 100644 --- a/net/nfc/llcp_core.c +++ b/net/nfc/llcp_core.c @@ -1089,6 +1089,7 @@ static void nfc_llcp_recv_hdlc(struct nfc_llcp_local = *local, if (sk->sk_state =3D=3D LLCP_CLOSED) { release_sock(sk); nfc_llcp_sock_put(llcp_sock); + return; } =20 /* Pass the payload upstream */ --=20 2.34.1