From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f182.google.com (mail-pl1-f182.google.com [209.85.214.182]) (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 C3B4248A2CE for ; Tue, 4 Aug 2026 21:39:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.182 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785879567; cv=none; b=Z6XcmOA8eWDBss2QSzbljNtJoEX8i2aLIaH5rNzgDkPT090vGy3GyWlZ32julJwP9bOmvnIxA2MSTAr+ou6NUZuvd7GzuNfSQzYinRUlIaVQVQ1cglpN4HyHxtM8g3DmyIWzkj4OpqQcQA4aG1gN4BhMfj2BH3F6lBkck3aLKFQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785879567; c=relaxed/simple; bh=c0jHAqCKMMLGqElB9P0Zc/ra2eBZhFiyVAmWgrs0dpc=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=jHuEd0sDVOdOFBCIVxsILJBjgnJkXXgOuodRgGGaxEmZTnM/jIhp1A2tOF/liF2A5FaOAjMZVkEl4BfZ0DZ957RtQe4TqeqmSOJ2oWdFLslbxqmAyTzuthB2bVbKqhPWKsFn+g3pdepqSyQ5aPcupHSfehRgQoJsCXj3Y9gQUFI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=e6SmcVV5; arc=none smtp.client-ip=209.85.214.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="e6SmcVV5" Received: by mail-pl1-f182.google.com with SMTP id d9443c01a7336-2cee9b74ee1so2839545ad.3 for ; Tue, 04 Aug 2026 14:39:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1785879564; x=1786484364; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to:content-type; bh=AVzPi9qdoodMQ73+79x+gG0Fw90m+Wzneqb+ihmK6gQ=; b=e6SmcVV5jfw8sFCaBIZVZtBXSOxoKLFnviVSNIVBBcs83peqIeViDqgJEo3jqTaY0d TR8/fjJmVb0hWCcPgGzufqhPCPutU31Xm4xTfJoOCv6teNG29GSiL+L0E48vQwy5jTQ3 mA/7d2LQHgAacqW5xthUbx9uNEk+JkD2qY11MFzXLwQ3R2pLOPBZe7zB45/csv+uoVDa 9WBxSmYkNRb7LDzTaCqlF0pqpjxCWtK+Z1M/wOpKyeQhWFNuWI4k+dD1XSOnqQGgwCaD djz6ydqXVE1xwO6hy1v8ouFil/C2+7sha/+kWbmx/lw4a3dnppMvVTTnxiIv4qzYIqVj 2M2Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1785879564; x=1786484364; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=AVzPi9qdoodMQ73+79x+gG0Fw90m+Wzneqb+ihmK6gQ=; b=ocVJvR57xlNDKfeWrDsVNsXyCZsc7MLdnvpWoaYSp8f83TsOlwLeKxMenuwUQUiD3W btUbVmZKMGPhEFNSErF9ZqPCxom84kMzsW0yOiV+/LSt48nU+0SUz8tTJqyCtph6ArGv g0qPCtJp37483aipnswusrlRODNO0UFYHXW7El+R+F4aKcqT9+qFzBGtJzuiIxIWwH6i Z9CAIqnFro8f07nrM21dYhfzsO+HinOnjHsKzFqDPzHx8EDdyLS86w/R0y7vCjC9ZixT uh9ZAHi4JzruqAjenOneLgxaJ7Y9UWzBDP09JHGF0gadWFzUr5aYQKv55i9oZ3ldnd2t xrGQ== X-Forwarded-Encrypted: i=1; AHgh+RqtW79qODez3XrLMGx8AgBQbsafnmvMspQMwnqjrbhiiAEw2k3U5KsRMcMQego3iQR40tJGu+t8ex3t@vger.kernel.org X-Gm-Message-State: AOJu0YxodKJ7a+ap1oTUneufgk1NnSaGs9gVaoUfyw/1s43ErnXJmx9R nraroiUewUuUcG+my2UXOZYfbl//bP9svMrpBY3p/Lg0KA2pQiGegBRW X-Gm-Gg: AR+sD11TOougx8JIJu2CV10aoPgxW9wXtpqR7GgEkV4XzNvqmvEb6N715mhgLvEbjtf GoFKDMmVmwnVxwzwGqsenfX5XA9X/7J6HJR/ka4r2WmIFdWMJKe9RCdoS28x4SB7dNIEHSjV7W1 NzHzA3ZkVQRZO0EtNvvajodIE5juP2NnX9K91yHWN+S1fIMIq1yQKoCdzTMyenK19hM1xLDj7nS lbA+1bK1zXp8QPjxoCBzPyRLQtPnjCBEcbCYNRQ2o/2/KmillDmdhYGO2wb0PaT8TZbceEY6FF9 lAVM+5M7YEjnk2RA9nWp1HRRkNvHUVpyigy4YnzR69u1EtqnJYDGgDP4x2xz4MAHlIxtc54Nb5k rhi2hfDm2y5C3KhLNoc6/omft6+Ee6ro3GEw/4ppCvoPsetbM0GYaII5P7tGCSEtdMv3vhm9Bp7 bNLW/FwNMNcWFf3w8j4p61jShDvk+oeZ5Y4HtXQIaai9aDbfAziGxsSAKC1UiXoRLqd7oaaZZN9 TvGtnD139Y9EkVNDgIpRT3pE8WQtiZQrRuK6I1pzFs= X-Received: by 2002:a05:6a21:a38d:b0:3bf:6fb1:ce0d with SMTP id adf61e73a8af0-3cb85ea3663mr1881337637.21.1785879564575; Tue, 04 Aug 2026 14:39:24 -0700 (PDT) Received: from LAPTOP-DPAKMOI4.it.purdue.edu (pal-210-106-74.itap.purdue.edu. [128.210.106.74]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-315867bc341sm14727379eec.27.2026.08.04.14.39.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 04 Aug 2026 14:39:24 -0700 (PDT) From: Yifei Gao To: "D . Wythe" , Dust Li , Sidraya Jayagond , Mahanta Jambigi , linux-rdma@vger.kernel.org, linux-s390@vger.kernel.org, netdev@vger.kernel.org Cc: Tony Lu , Wen Gu , Karsten Graul , Ursula Braun , Wenjia Zhang , linux-kernel@vger.kernel.org, Yifei Gao , stable@vger.kernel.org Subject: [PATCH] net/smc: fix sock refcount leak in smc_switch_conns() error path Date: Tue, 4 Aug 2026 21:39:17 +0000 Message-ID: <20260804213917.3413525-1-gyf161023@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-rdma@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit smc_switch_conns() takes a reference on the socket with sock_hold() before dropping conns_lock to prefetch a tx slot. On success the reference is released by the sock_put() after smc_switch_cursor(). When smc_cdc_get_free_slot() fails, however, the function jumps straight to err_out without a sock_put(), leaking the reference and leaving the socket unreclaimable. During SMC-R link failover with an exhausted backup link this leaks one reference per failing connection switch. Release the reference before jumping to err_out. The err_out label is also reached from the smc_switch_cursor() failure path, which has already done its own sock_put(), so the put must stay at the get_free_slot failure site rather than at the label. Fixes: c6f02ebeea3a ("net/smc: switch connections to alternate link") Cc: stable@vger.kernel.org Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Yifei Gao --- net/smc/smc_core.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c index cf6b620fef05..04c6ce608ec7 100644 --- a/net/smc/smc_core.c +++ b/net/smc/smc_core.c @@ -1148,8 +1148,10 @@ struct smc_link *smc_switch_conns(struct smc_link_group *lgr, read_unlock_bh(&lgr->conns_lock); /* pre-fetch buffer outside of send_lock, might sleep */ rc = smc_cdc_get_free_slot(conn, to_lnk, &wr_buf, NULL, &pend); - if (rc) + if (rc) { + sock_put(&smc->sk); goto err_out; + } /* avoid race with smcr_tx_sndbuf_nonempty() */ spin_lock_bh(&conn->send_lock); smc_switch_link_and_count(conn, to_lnk); -- 2.43.0