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 6091ACA9EA0 for ; Fri, 25 Oct 2019 14:06:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3379C20679 for ; Fri, 25 Oct 2019 14:06:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1572012376; bh=Z8kNSpZKICsj64i1BK953BmpbaZEYmjCSvxuGKfVnTE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=cOXFrdWXrv9rqCh9SyReyxUmOoHNnzD1Q+t/6he2r8IRIikOzpgSXs4zlWb6DX6lG 8akhGTzVb9E0s2olDQc3Qro+xwsVYpBRqBu57smQyUu/31JppA5rvqNDFkdpsA58aC AjHSzQSdyYLII3oG1ibc3I7OQZBbLdtU/gCaC/wQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2502939AbfJYOGO (ORCPT ); Fri, 25 Oct 2019 10:06:14 -0400 Received: from mail.kernel.org ([198.145.29.99]:49930 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2505164AbfJYNzu (ORCPT ); Fri, 25 Oct 2019 09:55:50 -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 CFD7D2084C; Fri, 25 Oct 2019 13:55:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1572011749; bh=Z8kNSpZKICsj64i1BK953BmpbaZEYmjCSvxuGKfVnTE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HS8j5x0leYeu6cn6WYV3nvvSHr1tzxCxFK58qNIN2GldyhST8zrY+kpaU9HAMyk5k FtfpibcbmdrqcmgfYIEGR1M3QQNwU2cOHRL4yVa811VzwNOYQ1gxVUTx5bNj5qCv5t QPfWgo3CW4BHZMdeoaNyujRHk2jaDNaQ17Q1lSxk= 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 5.3 28/33] RDMA/iwcm: Fix a lock inversion issue Date: Fri, 25 Oct 2019 09:55:00 -0400 Message-Id: <20191025135505.24762-28-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191025135505.24762-1-sashal@kernel.org> References: <20191025135505.24762-1-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 a68d0ccf67a43..2e48b59926c19 100644 --- a/drivers/infiniband/core/cma.c +++ b/drivers/infiniband/core/cma.c @@ -2396,9 +2396,10 @@ 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