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 F0676EE4996 for ; Tue, 22 Aug 2023 11:38:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235354AbjHVLi1 (ORCPT ); Tue, 22 Aug 2023 07:38:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37420 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235247AbjHVLiD (ORCPT ); Tue, 22 Aug 2023 07:38:03 -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 7A526E78; Tue, 22 Aug 2023 04:37:36 -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 0E6956538D; Tue, 22 Aug 2023 11:37:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 43D63C433CA; Tue, 22 Aug 2023 11:37:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1692704243; bh=Eyk4zl1JZYzGKhBc5ZOMVyD/BZx/6Hjfqpbnnq3Cvuw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mmSRuQPp+f/WbqThRdZoi1+ExiXJ8HPECPj4glQVHpZt/VKAyRs8O4Sym7RJEUBlY xPvOkFLLVAtSHD25Fm5VXaaEhi0FM4M9Ztv5TnPLQ3RaRxBCgZMpueIArNjg2Spg/U Y3nxk4dGe1wd6mI5wkqAB7Fj66pVqgs5hKajUxtZ5KK7WVZF1VFg5HkirqJ3cig+N+ yL3haEutpG+UD3QEsJZTGZYQsY1wv7El9tnJGHzfXzQ3Od66ZO9+5pG91oQTFAx7x3 Y3OC1MjHdmhCkQlpuAiTQ8DD6o3N/zg0Od4RdEIcHKLhhcjjcGu4yq63+bQQL9LGKW sxNQLn3u5/XPw== 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 5.10 2/3] scsi: qedi: Fix potential deadlock on &qedi_percpu->p_work_lock Date: Tue, 22 Aug 2023 07:37:18 -0400 Message-Id: <20230822113719.3551639-2-sashal@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230822113719.3551639-1-sashal@kernel.org> References: <20230822113719.3551639-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 5.10.191 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 cc2152c56d355..96e470746767a 100644 --- a/drivers/scsi/qedi/qedi_main.c +++ b/drivers/scsi/qedi/qedi_main.c @@ -1981,8 +1981,9 @@ 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; @@ -1993,7 +1994,7 @@ 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