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 0D02AEE4996 for ; Tue, 22 Aug 2023 11:38:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235403AbjHVLik (ORCPT ); Tue, 22 Aug 2023 07:38:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60602 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235278AbjHVLiR (ORCPT ); Tue, 22 Aug 2023 07:38:17 -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 199E3CDF; Tue, 22 Aug 2023 04:37:42 -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 37656653B5; Tue, 22 Aug 2023 11:37:35 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5E53BC433C7; Tue, 22 Aug 2023 11:37:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1692704254; bh=eEXlUWvTrWxU/nU7QIsiY/Df3hcXrpaKMgp6vLnuyOg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sC5Hivkx1o4l3t6kQPBBVja+0IgR+dv3uG3NmKtUuwiSmumfhgooXbKbXclgviOSk +s2AK61/OnAfxzG0qkWhik2CZ8aSchOviuQwIBXQ73S8/RXOMlfxkMrLTTBVng3HHw wn9io+/1x7w0hFKswXG3fik5rUs3jZU3sNYay1h4luKoqpIP+AEoJRVlwjostz1RMG jxJCFUx19ZAoRmnCcc5/DBkLv3wEi/CMXut41bR+Yov0nd2dbQjJ/UDcPY7NQwQCil RsGSvQkM8W1jrzG0hmVkLtckeMT3+5u56cqED3sHdMsgY5YUL6odxVhe7413HzEebp 9uLLG7gYkFf/A== 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 4.19 2/2] scsi: qedi: Fix potential deadlock on &qedi_percpu->p_work_lock Date: Tue, 22 Aug 2023 07:37:30 -0400 Message-Id: <20230822113730.3551725-2-sashal@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230822113730.3551725-1-sashal@kernel.org> References: <20230822113730.3551725-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 4.19.292 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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 ab66e1f0fdfa3..7a179cfc01ed2 100644 --- a/drivers/scsi/qedi/qedi_main.c +++ b/drivers/scsi/qedi/qedi_main.c @@ -1864,8 +1864,9 @@ 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; @@ -1876,7 +1877,7 @@ 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