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=-10.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,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 DD4DDC388F3 for ; Mon, 30 Sep 2019 23:17:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BD8E821855 for ; Mon, 30 Sep 2019 23:17:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731806AbfI3XRW (ORCPT ); Mon, 30 Sep 2019 19:17:22 -0400 Received: from mail-pg1-f194.google.com ([209.85.215.194]:33322 "EHLO mail-pg1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729057AbfI3XRW (ORCPT ); Mon, 30 Sep 2019 19:17:22 -0400 Received: by mail-pg1-f194.google.com with SMTP id q1so219118pgb.0; Mon, 30 Sep 2019 16:17:21 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=ocb0Btdcve+bO+wvymS9VkmrTcFGK8V6696tRMbHc+k=; b=BhCKdjvdhTBZ69uqLHX2rGhrP36s1pp3LebDq630hlx5pZd1TJU2aRe3anlZwZiRp/ dPE5Qs3uUSvt9BIhLynmIdZR+pcKG3bzSPL96tfKysMZkP9kwMc+rjXh4ToFiNqvT6NC iUGtYjJaiOilU71VexFOrjk5qiBbq9Q2P4XIgLZ3FP6FMG7KhT1eoTkxXuO1GH0aKM11 wHUJY0b0Z8MDl7ScLdgRp/XoAAJ8HtsxhgSpRyGhXGN9gsYWdiF+CmNVw0Me5tJGSKSj 1q9BYcosEACI0JScPOzFtV+gPDlX0AC9P9frw2XCieCHmFOByFFtVuCrPq8zksVnMdco 9+Wg== X-Gm-Message-State: APjAAAVy29WaWbqZ+2ptOMnkFdkcoKZKZsLePPDWHUl6tYW81YnCyQj8 yul+f2I1mPmEKje7oPzVe9k= X-Google-Smtp-Source: APXvYqxqlWVNGWrOUIUEPZcvOX2yzzKdpmHAFcs908qNTdxO1EMIqimea5iYW00BRDuKt2JUsKyy1g== X-Received: by 2002:aa7:9104:: with SMTP id 4mr24407619pfh.176.1569885441335; Mon, 30 Sep 2019 16:17:21 -0700 (PDT) Received: from desktop-bart.svl.corp.google.com ([2620:15c:2cd:202:4308:52a3:24b6:2c60]) by smtp.gmail.com with ESMTPSA id l7sm585406pjy.12.2019.09.30.16.17.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 30 Sep 2019 16:17:20 -0700 (PDT) From: Bart Van Assche To: Jason Gunthorpe Cc: Leon Romanovsky , Doug Ledford , linux-rdma@vger.kernel.org, Bart Van Assche , Or Gerlitz , Steve Wise , Sagi Grimberg , Bernard Metzler , Krishnamraju Eraparaju , stable@vger.kernel.org Subject: [PATCH 02/15] RDMA/iwcm: Fix a lock inversion issue Date: Mon, 30 Sep 2019 16:16:54 -0700 Message-Id: <20190930231707.48259-3-bvanassche@acm.org> X-Mailer: git-send-email 2.23.0.444.g18eeb5a265-goog In-Reply-To: <20190930231707.48259-1-bvanassche@acm.org> References: <20190930231707.48259-1-bvanassche@acm.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org 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 Cc: Or Gerlitz Cc: Steve Wise Cc: Sagi Grimberg Cc: Bernard Metzler Cc: Krishnamraju Eraparaju Cc: Fixes: de910bd92137 ("RDMA/cma: Simplify locking needed for serialization of callbacks"; v2.6.27). Signed-off-by: Bart Van Assche --- 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 0e3cf3461999..d78f67623f24 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); -- 2.23.0.444.g18eeb5a265-goog