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 X-Spam-Level: X-Spam-Status: No, score=-18.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E428EC433E0 for ; Tue, 2 Feb 2021 13:44:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9FB1664FCE for ; Tue, 2 Feb 2021 13:44:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232636AbhBBNoG (ORCPT ); Tue, 2 Feb 2021 08:44:06 -0500 Received: from mail.kernel.org ([198.145.29.99]:35064 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232661AbhBBNk3 (ORCPT ); Tue, 2 Feb 2021 08:40:29 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 7EFEF64F5F; Tue, 2 Feb 2021 13:39:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1612273189; bh=yPb8DO6ChUmx2eSgUraMKtt1Bbk4tuqYUv5KZIIUEws=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XRn6HkOifLVaErlnHI3Jfzw+vXv7EB5xh6WjkJYiOwK5nQGhFVotg49qHmY5QbYEu 9p3M6P63IS4sWx6h0k229X+UZcinyWsGk8h4wby14uGKN0C9tfIGzWgQZuowcomY0I O6gXX0x8m8WR/VGA04/fdYF8g/dosOUGLiFcyLS8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Baoquan He , Dan Carpenter , Pingfan Liu , "Rafael J. Wysocki" Subject: [PATCH 5.10 006/142] kernel: kexec: remove the lock operation of system_transition_mutex Date: Tue, 2 Feb 2021 14:36:09 +0100 Message-Id: <20210202132957.958567172@linuxfoundation.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210202132957.692094111@linuxfoundation.org> References: <20210202132957.692094111@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Baoquan He commit 56c91a18432b631ca18438841fd1831ef756cabf upstream. Function kernel_kexec() is called with lock system_transition_mutex held in reboot system call. While inside kernel_kexec(), it will acquire system_transition_mutex agin. This will lead to dead lock. The dead lock should be easily triggered, it hasn't caused any failure report just because the feature 'kexec jump' is almost not used by anyone as far as I know. An inquiry can be made about who is using 'kexec jump' and where it's used. Before that, let's simply remove the lock operation inside CONFIG_KEXEC_JUMP ifdeffery scope. Fixes: 55f2503c3b69 ("PM / reboot: Eliminate race between reboot and suspend") Signed-off-by: Baoquan He Reported-by: Dan Carpenter Reviewed-by: Pingfan Liu Cc: 4.19+ # 4.19+ Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman --- kernel/kexec_core.c | 2 -- 1 file changed, 2 deletions(-) --- a/kernel/kexec_core.c +++ b/kernel/kexec_core.c @@ -1135,7 +1135,6 @@ int kernel_kexec(void) #ifdef CONFIG_KEXEC_JUMP if (kexec_image->preserve_context) { - lock_system_sleep(); pm_prepare_console(); error = freeze_processes(); if (error) { @@ -1198,7 +1197,6 @@ int kernel_kexec(void) thaw_processes(); Restore_console: pm_restore_console(); - unlock_system_sleep(); } #endif