From patchwork Mon May 16 19:36:25 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "gregkh@linuxfoundation.org" X-Patchwork-Id: 573690 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 C5730C3A59E for ; Mon, 16 May 2022 20:13:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346808AbiEPUMG (ORCPT ); Mon, 16 May 2022 16:12:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57540 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350561AbiEPUBV (ORCPT ); Mon, 16 May 2022 16:01:21 -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 9FC0A49FAE; Mon, 16 May 2022 12:55:33 -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 31D2E60FD9; Mon, 16 May 2022 19:55:32 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 224E5C34115; Mon, 16 May 2022 19:55:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1652730931; bh=EwrlZFOvzJnjMTJ2FyUy85Q/vhUk54CTxzJFzMEnSow=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YRfmpfg2IkhsoTRP76maCmxcghA2OAjC3LhOKJWNVlaXLhvoaOO3PC8w2D0DLAKSD 7ppZUIPq1wX6zWJr1WiVefef3xCP2458mDKrFLVCbOlNNCQg7YtHTSNU8hFVWmi9Nd wOrhzLvk8W8uimKOgBuurhTCkOZRKOUI6uIwO74I= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Duoming Zhou , Shiraz Saleem , Jason Gunthorpe , Sasha Levin Subject: [PATCH 5.17 051/114] RDMA/irdma: Fix deadlock in irdma_cleanup_cm_core() Date: Mon, 16 May 2022 21:36:25 +0200 Message-Id: <20220516193626.959658720@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220516193625.489108457@linuxfoundation.org> References: <20220516193625.489108457@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Duoming Zhou [ Upstream commit 679ab61bf5f5f519377d812afb4fb93634782c74 ] There is a deadlock in irdma_cleanup_cm_core(), which is shown below: (Thread 1) | (Thread 2) | irdma_schedule_cm_timer() irdma_cleanup_cm_core() | add_timer() spin_lock_irqsave() //(1) | (wait a time) ... | irdma_cm_timer_tick() del_timer_sync() | spin_lock_irqsave() //(2) (wait timer to stop) | ... We hold cm_core->ht_lock in position (1) of thread 1 and use del_timer_sync() to wait timer to stop, but timer handler also need cm_core->ht_lock in position (2) of thread 2. As a result, irdma_cleanup_cm_core() will block forever. This patch removes the check of timer_pending() in irdma_cleanup_cm_core(), because the del_timer_sync() function will just return directly if there isn't a pending timer. As a result, the lock is redundant, because there is no resource it could protect. Link: https://lore.kernel.org/r/20220418153322.42524-1-duoming@zju.edu.cn Signed-off-by: Duoming Zhou Reviewed-by: Shiraz Saleem Signed-off-by: Jason Gunthorpe Signed-off-by: Sasha Levin --- drivers/infiniband/hw/irdma/cm.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) diff --git a/drivers/infiniband/hw/irdma/cm.c b/drivers/infiniband/hw/irdma/cm.c index 082a3ddb0fa3..632f65e53b63 100644 --- a/drivers/infiniband/hw/irdma/cm.c +++ b/drivers/infiniband/hw/irdma/cm.c @@ -3242,15 +3242,10 @@ enum irdma_status_code irdma_setup_cm_core(struct irdma_device *iwdev, */ void irdma_cleanup_cm_core(struct irdma_cm_core *cm_core) { - unsigned long flags; - if (!cm_core) return; - spin_lock_irqsave(&cm_core->ht_lock, flags); - if (timer_pending(&cm_core->tcp_timer)) - del_timer_sync(&cm_core->tcp_timer); - spin_unlock_irqrestore(&cm_core->ht_lock, flags); + del_timer_sync(&cm_core->tcp_timer); destroy_workqueue(cm_core->event_wq); cm_core->dev->ws_reset(&cm_core->iwdev->vsi);