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Mon, 20 Jul 2026 12:38:15 -0700 (PDT) From: Shuangpeng Bai To: david@ixit.cz, oe-linux-nfc@lists.linux.dev Cc: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Shuangpeng Bai Subject: [PATCH v2] nfc: llcp: Fix nfc_dev refcount leak in connect Date: Mon, 20 Jul 2026 15:37:59 -0400 Message-ID: <20260720193759.1773705-1-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 llcp_sock_connect() takes a reference to the NFC device and keeps it while a connection is active. For a nonblocking connection, sock_wait_state() returns -EINPROGRESS while the socket remains in LLCP_CONNECTING. If the socket is released before reaching LLCP_CONNECTED, llcp_sock_destruct() does not drop the reference because it only handles connected sockets. Drop the device reference in llcp_sock_release() when unlinking a connecting socket. At this point llcp_sock->dev is still valid, unlike after a failed blocking connection has cleared it. Fixes: b4011239a08e ("NFC: llcp: Fix non blocking sockets connections") Link: https://lore.kernel.org/r/20260707183518.1888697-1-shuangpeng.kernel@gmail.com Signed-off-by: Shuangpeng Bai --- Changes in v2: - Move the device put from llcp_sock_destruct() to llcp_sock_release() to avoid dereferencing a NULL llcp_sock->dev after a failed blocking connect. - Add Fixes and Link tags. net/nfc/llcp_sock.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/net/nfc/llcp_sock.c b/net/nfc/llcp_sock.c index feab29fc62f4..0a3d87c2c9b3 100644 --- a/net/nfc/llcp_sock.c +++ b/net/nfc/llcp_sock.c @@ -633,10 +633,12 @@ static int llcp_sock_release(struct socket *sock) if (sock->type == SOCK_RAW) nfc_llcp_sock_unlink(&local->raw_sockets, sk); - else if (sk->sk_state == LLCP_CONNECTING) + else if (sk->sk_state == LLCP_CONNECTING) { nfc_llcp_sock_unlink(&local->connecting_sockets, sk); - else + nfc_put_device(llcp_sock->dev); + } else { nfc_llcp_sock_unlink(&local->sockets, sk); + } if (llcp_sock->reserved_ssap < LLCP_SAP_MAX) nfc_llcp_put_ssap(llcp_sock->local, llcp_sock->ssap); -- 2.43.0