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 C1FB3EE4996 for ; Tue, 22 Aug 2023 11:37:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235027AbjHVLh1 (ORCPT ); Tue, 22 Aug 2023 07:37:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39232 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235038AbjHVLhZ (ORCPT ); Tue, 22 Aug 2023 07:37:25 -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 799FEE51; Tue, 22 Aug 2023 04:36:58 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 598C7628A7; Tue, 22 Aug 2023 11:36:02 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9840BC433CD; Tue, 22 Aug 2023 11:36:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1692704161; bh=Ym6qa0ZO8dJoVvGDoxNGVPBBoiW4ul0ekcw4PYRjNXQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=r99IO3WissmJ3wmcuks7x6Vfl5dZD61jM6tT92aVUK4BceSwSQg+heSaOwab0P0/a BKtp1bx0C92xcLXDx1CQwaBJAj2mM31gNME+yZa7us7MjIHzvyFeGhlQm87KjBv5lh ckidKztJZryJxKFLf23VMXMM1KeGI4Kehn7K7NeePrz6H1waFhddYqCW8SL0LtDLvn Yzi53tIv0UABmI8VoyUcgxPNhTlvYF5FKLyFxYPQHrWxqKMXZisNGux+aZ6YZjkpVa TslKlXLL8OsTCAcpc3ND2JWH/tzj7aq0R+Si25AbPke0j5029JZyhpYtxW9n2KHfNy UlUjPrObmTA2w== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Chengfeng Ye , Manish Rangankar , "Martin K . Petersen" , Sasha Levin , njavali@marvell.com, GR-QLogic-Storage-Upstream@marvell.com, jejb@linux.ibm.com, linux-scsi@vger.kernel.org Subject: [PATCH AUTOSEL 6.4 04/11] scsi: qedi: Fix potential deadlock on &qedi_percpu->p_work_lock Date: Tue, 22 Aug 2023 07:35:46 -0400 Message-Id: <20230822113553.3551206-4-sashal@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230822113553.3551206-1-sashal@kernel.org> References: <20230822113553.3551206-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.4.11 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Chengfeng Ye [ Upstream commit dd64f80587190265ca8a0f4be6c64c2fda6d3ac2 ] As &qedi_percpu->p_work_lock is acquired by hard IRQ qedi_msix_handler(), other acquisitions of the same lock under process context should disable IRQ, otherwise deadlock could happen if the IRQ preempts the execution while the lock is held in process context on the same CPU. qedi_cpu_offline() is one such function which acquires the lock in process context. [Deadlock Scenario] qedi_cpu_offline() ->spin_lock(&p->p_work_lock) ->qedi_msix_handler() ->edi_process_completions() ->spin_lock_irqsave(&p->p_work_lock, flags); (deadlock here) This flaw was found by an experimental static analysis tool I am developing for IRQ-related deadlocks. The tentative patch fix the potential deadlock by spin_lock_irqsave() under process context. Signed-off-by: Chengfeng Ye Link: https://lore.kernel.org/r/20230726125655.4197-1-dg573847474@gmail.com Acked-by: Manish Rangankar Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin --- drivers/scsi/qedi/qedi_main.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/scsi/qedi/qedi_main.c b/drivers/scsi/qedi/qedi_main.c index ef62dbbc1868e..1106d26113888 100644 --- a/drivers/scsi/qedi/qedi_main.c +++ b/drivers/scsi/qedi/qedi_main.c @@ -1977,8 +1977,9 @@ static int qedi_cpu_offline(unsigned int cpu) struct qedi_percpu_s *p = this_cpu_ptr(&qedi_percpu); struct qedi_work *work, *tmp; struct task_struct *thread; + unsigned long flags; - spin_lock_bh(&p->p_work_lock); + spin_lock_irqsave(&p->p_work_lock, flags); thread = p->iothread; p->iothread = NULL; @@ -1989,7 +1990,7 @@ static int qedi_cpu_offline(unsigned int cpu) kfree(work); } - spin_unlock_bh(&p->p_work_lock); + spin_unlock_irqrestore(&p->p_work_lock, flags); if (thread) kthread_stop(thread); return 0; -- 2.40.1