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 D3B86EE49B5 for ; Tue, 22 Aug 2023 11:37:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235132AbjHVLhw (ORCPT ); Tue, 22 Aug 2023 07:37:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46422 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235145AbjHVLhn (ORCPT ); Tue, 22 Aug 2023 07:37:43 -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 ED24BE68; Tue, 22 Aug 2023 04:37:21 -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 D08F365375; Tue, 22 Aug 2023 11:36:35 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 189D9C433C9; Tue, 22 Aug 2023 11:36:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1692704195; bh=qpwNtJsV7UyMeH2/7ix05rpVptjCeBIH0tiJTTWKx50=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MfuLwSPv9rBMftrAzM6lyBOOtR1J7UE1SVPEbwKQyIlcY1SJHz9O+m51M85jJXvrM dA9xKYtuvxHthMwpIC9NvtqTnehCgD6VEVTtpjlBm+zHxt4XyQdCBxRLpyxevZk8U9 zpnhfcWD3Q7zsP7h5+bzWCAqHRV3SlGYkVSiWqfgVmdj+oSL2ONeo6HdLVwggXw9Km ZqnoLqiO36ef2x/0MoynUod5NZjgmdf4sxmllrFPREL5ckn8VXJ8Eg+DecKQ64Ux3k mSFnCh/xnwqN38KAqjWt74dMnTfHm+wyDEc8v1x9F1zAcDxHUsCWHA7nqnV3B8U29t pZx55lg3CLYKw== 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 6.1 04/10] scsi: qedi: Fix potential deadlock on &qedi_percpu->p_work_lock Date: Tue, 22 Aug 2023 07:36:22 -0400 Message-Id: <20230822113628.3551393-4-sashal@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230822113628.3551393-1-sashal@kernel.org> References: <20230822113628.3551393-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.1.46 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 9fd68d362698f..2ee109fb65616 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