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 X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 899ACCA9EBC for ; Fri, 25 Oct 2019 13:58:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 62113222C9 for ; Fri, 25 Oct 2019 13:58:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1572011922; bh=BT5g7okK7GOY7awUj1RlSha07wwJtV+TgL6wEfrCD0Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=lCjtNSmb9lB9rANHXcKOpe5XDJ2rBfBGYMc5nachCmMDR3sYo1/lIspI2OxpDkFa6 LCVq1mjWK55wgadCLQju/BpbBj5s5YhyoN3nYQdA9J0wlUjrU1m0U3+ybD8OOLrHg8 Wii1a+0gwqpwZfzW/L/M1gFS6D5eNE7L+3J7JDUc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2505652AbfJYN6l (ORCPT ); Fri, 25 Oct 2019 09:58:41 -0400 Received: from mail.kernel.org ([198.145.29.99]:54038 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2505583AbfJYN6h (ORCPT ); Fri, 25 Oct 2019 09:58:37 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 669DE21E6F; Fri, 25 Oct 2019 13:58:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1572011916; bh=BT5g7okK7GOY7awUj1RlSha07wwJtV+TgL6wEfrCD0Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Stck5q1ZHkjU0IDHxuy5URfrRjszvgxku/x5scNMhlKuCHzuWxEMVcEpuowowHcW2 TgRUcSomHVTfItjjx00VQ8PmFDnHCk0WoTpI/yKMmhOuzzJu/CkUKyw0iUCBzWtmCX hU1IwQCu2qpEWZ55XWl0YxPYE832b8Ucgwd1JBEU= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Bart Van Assche , Jason Gunthorpe , Sasha Levin , linux-rdma@vger.kernel.org Subject: [PATCH AUTOSEL 4.9 18/20] RDMA/iwcm: Fix a lock inversion issue Date: Fri, 25 Oct 2019 09:57:58 -0400 Message-Id: <20191025135801.25739-18-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191025135801.25739-1-sashal@kernel.org> References: <20191025135801.25739-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Bart Van Assche [ Upstream commit b66f31efbdad95ec274345721d99d1d835e6de01 ] This patch fixes the lock inversion complaint: ============================================ WARNING: possible recursive locking detected 5.3.0-rc7-dbg+ #1 Not tainted -------------------------------------------- kworker/u16:6/171 is trying to acquire lock: 00000000035c6e6c (&id_priv->handler_mutex){+.+.}, at: rdma_destroy_id+0x78/0x4a0 [rdma_cm] but task is already holding lock: 00000000bc7c307d (&id_priv->handler_mutex){+.+.}, at: iw_conn_req_handler+0x151/0x680 [rdma_cm] other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&id_priv->handler_mutex); lock(&id_priv->handler_mutex); *** DEADLOCK *** May be due to missing lock nesting notation 3 locks held by kworker/u16:6/171: #0: 00000000e2eaa773 ((wq_completion)iw_cm_wq){+.+.}, at: process_one_work+0x472/0xac0 #1: 000000001efd357b ((work_completion)(&work->work)#3){+.+.}, at: process_one_work+0x476/0xac0 #2: 00000000bc7c307d (&id_priv->handler_mutex){+.+.}, at: iw_conn_req_handler+0x151/0x680 [rdma_cm] stack backtrace: CPU: 3 PID: 171 Comm: kworker/u16:6 Not tainted 5.3.0-rc7-dbg+ #1 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 Workqueue: iw_cm_wq cm_work_handler [iw_cm] Call Trace: dump_stack+0x8a/0xd6 __lock_acquire.cold+0xe1/0x24d lock_acquire+0x106/0x240 __mutex_lock+0x12e/0xcb0 mutex_lock_nested+0x1f/0x30 rdma_destroy_id+0x78/0x4a0 [rdma_cm] iw_conn_req_handler+0x5c9/0x680 [rdma_cm] cm_work_handler+0xe62/0x1100 [iw_cm] process_one_work+0x56d/0xac0 worker_thread+0x7a/0x5d0 kthread+0x1bc/0x210 ret_from_fork+0x24/0x30 This is not a bug as there are actually two lock classes here. Link: https://lore.kernel.org/r/20190930231707.48259-3-bvanassche@acm.org Fixes: de910bd92137 ("RDMA/cma: Simplify locking needed for serialization of callbacks") Signed-off-by: Bart Van Assche Reviewed-by: Jason Gunthorpe Signed-off-by: Jason Gunthorpe Signed-off-by: Sasha Levin --- drivers/infiniband/core/cma.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c index 85d4ef319c905..dcfbf326f45c9 100644 --- a/drivers/infiniband/core/cma.c +++ b/drivers/infiniband/core/cma.c @@ -2119,9 +2119,10 @@ static int iw_conn_req_handler(struct iw_cm_id *cm_id, conn_id->cm_id.iw = NULL; cma_exch(conn_id, RDMA_CM_DESTROYING); mutex_unlock(&conn_id->handler_mutex); + mutex_unlock(&listen_id->handler_mutex); cma_deref_id(conn_id); rdma_destroy_id(&conn_id->id); - goto out; + return ret; } mutex_unlock(&conn_id->handler_mutex); -- 2.20.1