From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x227e7Gj/g6jhVWrSMC9km2u8WVWjyurfK7dEw7vHPYFkLQD/1C4f4X0E0+44cNc/oKDmo3Zq ARC-Seal: i=1; a=rsa-sha256; t=1519412261; cv=none; d=google.com; s=arc-20160816; b=OYMdIfMWHmJS9G30le8AHcY/PnlgPjX7UPESyaOZdpEcdz7KD/kfAhQko1WCzE/yYo w+PNONcR5P8MYliS32H/klVcBA2pl36EdMx0DXTFHW0WJ+KXK5HZiwoHwDyVlp79Jocu y/XMkzyDWBmh7C0/W8E5zmHWaQcbjkPAXK567E816yjTGzJupcLvNkqFHqwaiNJ+TSk9 QDdzTTZhxkjNgHFK5/zo90itLQDL3K4gx9qSdCofiVXy3mMLE8cVXHXyBrDhZvJLEZSu in7HS493kYI9Q3qsFIyKt6ZyNxn2p9qYURWI8jewWg8safAYnLVnBS7yCxL6TQVvMFO2 PeLg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=gNZx/VKeFMRlLrkxd6ROYuPtdRCqPk27ogQY3hxq8d8=; b=iWyep3K/5uS6KV2UffzW0g9Q7UoFn3PYldzBdKf03g41iIPLUWJjX9MT9hE/ZotshS Z4JASDTzJnhLlM69i69QEGSJPNZZYu0AiGD6lfMPay2XyTy5D88Fb8vsLnTR/cLwxXGM Y+lDEKvNMtqm56wY8bUCz5YOsknTFdCuWkEcnStp22afDo/RgMHelNY+FtPvX9YUfbM2 CtjisdbWqX8jxZovu8KT1BZGjhQ/QwsfbOyOHK0MHvMBcfDVEqeXetvPXlcjsdptPi3c 32egHI5b8Tyb6tbD2K3HTOdMQc+nmtMjAPqATAQZdnqeQNj5DErBZCpv7oGWNh9aoBeB O9ew== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.71.90 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.71.90 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot , Sowmini Varadhan , Santosh Shilimkar , "David S. Miller" Subject: [PATCH 4.15 20/45] rds: tcp: atomically purge entries from rds_tcp_conn_list during netns delete Date: Fri, 23 Feb 2018 19:28:59 +0100 Message-Id: <20180223170718.465791414@linuxfoundation.org> X-Mailer: git-send-email 2.16.2 In-Reply-To: <20180223170715.197760019@linuxfoundation.org> References: <20180223170715.197760019@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1593218326118294645?= X-GMAIL-MSGID: =?utf-8?q?1593219231490963117?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sowmini Varadhan commit f10b4cff98c6977668434fbf5dd58695eeca2897 upstream. The rds_tcp_kill_sock() function parses the rds_tcp_conn_list to find the rds_connection entries marked for deletion as part of the netns deletion under the protection of the rds_tcp_conn_lock. Since the rds_tcp_conn_list tracks rds_tcp_connections (which have a 1:1 mapping with rds_conn_path), multiple tc entries in the rds_tcp_conn_list will map to a single rds_connection, and will be deleted as part of the rds_conn_destroy() operation that is done outside the rds_tcp_conn_lock. The rds_tcp_conn_list traversal done under the protection of rds_tcp_conn_lock should not leave any doomed tc entries in the list after the rds_tcp_conn_lock is released, else another concurrently executiong netns delete (for a differnt netns) thread may trip on these entries. Reported-by: syzbot Signed-off-by: Sowmini Varadhan Acked-by: Santosh Shilimkar Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/rds/tcp.c | 9 +++++++-- net/rds/tcp.h | 1 + 2 files changed, 8 insertions(+), 2 deletions(-) --- a/net/rds/tcp.c +++ b/net/rds/tcp.c @@ -307,7 +307,8 @@ static void rds_tcp_conn_free(void *arg) rdsdebug("freeing tc %p\n", tc); spin_lock_irqsave(&rds_tcp_conn_lock, flags); - list_del(&tc->t_tcp_node); + if (!tc->t_tcp_node_detached) + list_del(&tc->t_tcp_node); spin_unlock_irqrestore(&rds_tcp_conn_lock, flags); kmem_cache_free(rds_tcp_conn_slab, tc); @@ -532,8 +533,12 @@ static void rds_tcp_kill_sock(struct net if (net != c_net || !tc->t_sock) continue; - if (!list_has_conn(&tmp_list, tc->t_cpath->cp_conn)) + if (!list_has_conn(&tmp_list, tc->t_cpath->cp_conn)) { list_move_tail(&tc->t_tcp_node, &tmp_list); + } else { + list_del(&tc->t_tcp_node); + tc->t_tcp_node_detached = true; + } } spin_unlock_irq(&rds_tcp_conn_lock); list_for_each_entry_safe(tc, _tc, &tmp_list, t_tcp_node) { --- a/net/rds/tcp.h +++ b/net/rds/tcp.h @@ -12,6 +12,7 @@ struct rds_tcp_incoming { struct rds_tcp_connection { struct list_head t_tcp_node; + bool t_tcp_node_detached; struct rds_conn_path *t_cpath; /* t_conn_path_lock synchronizes the connection establishment between * rds_tcp_accept_one and rds_tcp_conn_path_connect