From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5FBDFC43219 for ; Tue, 5 Apr 2022 09:52:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243295AbiDEJj1 (ORCPT ); Tue, 5 Apr 2022 05:39:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52040 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239774AbiDEIUw (ORCPT ); Tue, 5 Apr 2022 04:20:52 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 863A4BFC; Tue, 5 Apr 2022 01:18:52 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 220E260B10; Tue, 5 Apr 2022 08:18:52 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 05446C385A1; Tue, 5 Apr 2022 08:18:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649146731; bh=ZhdGQAmWHHMFrACJpTe69z62VUQvcrG8v0VNxiUGKOw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dO/1oAAHS+fkJcH3gAXbuUkJeTh8p/Ctosnc/JVST0hJ54330LKH6znLnOj2FhIki r+FW+g4mRcNDUrk4ViYamEpd7EnHz2MlCjKd/YHm5GrGg9U4pTkfqeSPdqzNGt23bV KazmQfO5zoVHl/JGM29Q0Zh1GrGBIPweVA/3TCXo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Chris Leech , Christoph Hellwig , Sasha Levin Subject: [PATCH 5.17 0867/1126] nvme-tcp: lockdep: annotate in-kernel sockets Date: Tue, 5 Apr 2022 09:26:54 +0200 Message-Id: <20220405070432.986230914@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220405070407.513532867@linuxfoundation.org> References: <20220405070407.513532867@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Chris Leech [ Upstream commit 841aee4d75f18fdfb53935080b03de0c65e9b92c ] Put NVMe/TCP sockets in their own class to avoid some lockdep warnings. Sockets created by nvme-tcp are not exposed to user-space, and will not trigger certain code paths that the general socket API exposes. Lockdep complains about a circular dependency between the socket and filesystem locks, because setsockopt can trigger a page fault with a socket lock held, but nvme-tcp sends requests on the socket while file system locks are held. ====================================================== WARNING: possible circular locking dependency detected 5.15.0-rc3 #1 Not tainted ------------------------------------------------------ fio/1496 is trying to acquire lock: (sk_lock-AF_INET){+.+.}-{0:0}, at: tcp_sendpage+0x23/0x80 but task is already holding lock: (&xfs_dir_ilock_class/5){+.+.}-{3:3}, at: xfs_ilock+0xcf/0x290 [xfs] which lock already depends on the new lock. other info that might help us debug this: chain exists of: sk_lock-AF_INET --> sb_internal --> &xfs_dir_ilock_class/5 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&xfs_dir_ilock_class/5); lock(sb_internal); lock(&xfs_dir_ilock_class/5); lock(sk_lock-AF_INET); *** DEADLOCK *** 6 locks held by fio/1496: #0: (sb_writers#13){.+.+}-{0:0}, at: path_openat+0x9fc/0xa20 #1: (&inode->i_sb->s_type->i_mutex_dir_key){++++}-{3:3}, at: path_openat+0x296/0xa20 #2: (sb_internal){.+.+}-{0:0}, at: xfs_trans_alloc_icreate+0x41/0xd0 [xfs] #3: (&xfs_dir_ilock_class/5){+.+.}-{3:3}, at: xfs_ilock+0xcf/0x290 [xfs] #4: (hctx->srcu){....}-{0:0}, at: hctx_lock+0x51/0xd0 #5: (&queue->send_mutex){+.+.}-{3:3}, at: nvme_tcp_queue_rq+0x33e/0x380 [nvme_tcp] This annotation lets lockdep analyze nvme-tcp controlled sockets independently of what the user-space sockets API does. Link: https://lore.kernel.org/linux-nvme/CAHj4cs9MDYLJ+q+2_GXUK9HxFizv2pxUryUR0toX974M040z7g@mail.gmail.com/ Signed-off-by: Chris Leech Signed-off-by: Christoph Hellwig Signed-off-by: Sasha Levin --- drivers/nvme/host/tcp.c | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c index 65e00c64a588..d66e2de044e0 100644 --- a/drivers/nvme/host/tcp.c +++ b/drivers/nvme/host/tcp.c @@ -30,6 +30,44 @@ static int so_priority; module_param(so_priority, int, 0644); MODULE_PARM_DESC(so_priority, "nvme tcp socket optimize priority"); +#ifdef CONFIG_DEBUG_LOCK_ALLOC +/* lockdep can detect a circular dependency of the form + * sk_lock -> mmap_lock (page fault) -> fs locks -> sk_lock + * because dependencies are tracked for both nvme-tcp and user contexts. Using + * a separate class prevents lockdep from conflating nvme-tcp socket use with + * user-space socket API use. + */ +static struct lock_class_key nvme_tcp_sk_key[2]; +static struct lock_class_key nvme_tcp_slock_key[2]; + +static void nvme_tcp_reclassify_socket(struct socket *sock) +{ + struct sock *sk = sock->sk; + + if (WARN_ON_ONCE(!sock_allow_reclassification(sk))) + return; + + switch (sk->sk_family) { + case AF_INET: + sock_lock_init_class_and_name(sk, "slock-AF_INET-NVME", + &nvme_tcp_slock_key[0], + "sk_lock-AF_INET-NVME", + &nvme_tcp_sk_key[0]); + break; + case AF_INET6: + sock_lock_init_class_and_name(sk, "slock-AF_INET6-NVME", + &nvme_tcp_slock_key[1], + "sk_lock-AF_INET6-NVME", + &nvme_tcp_sk_key[1]); + break; + default: + WARN_ON_ONCE(1); + } +} +#else +static void nvme_tcp_reclassify_socket(struct socket *sock) { } +#endif + enum nvme_tcp_send_state { NVME_TCP_SEND_CMD_PDU = 0, NVME_TCP_SEND_H2C_PDU, @@ -1469,6 +1507,8 @@ static int nvme_tcp_alloc_queue(struct nvme_ctrl *nctrl, goto err_destroy_mutex; } + nvme_tcp_reclassify_socket(queue->sock); + /* Single syn retry */ tcp_sock_set_syncnt(queue->sock->sk, 1); -- 2.34.1