From patchwork Tue Feb 2 13:37:43 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 376007 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, URIBL_RED, USER_AGENT_GIT autolearn=ham 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 14A4AC433E9 for ; Tue, 2 Feb 2021 19:27:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D1B6E60295 for ; Tue, 2 Feb 2021 19:27:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233348AbhBBT1c (ORCPT ); Tue, 2 Feb 2021 14:27:32 -0500 Received: from mail.kernel.org ([198.145.29.99]:45424 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233529AbhBBN7B (ORCPT ); Tue, 2 Feb 2021 08:59:01 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 35BA964F72; Tue, 2 Feb 2021 13:46:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1612273581; bh=CaVfVYIxP1gyPkUtrnppSfw4+6q6Ngh3L0VAOaX9+Po=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wwCvExL2VVagj5kuXzQ22ItNyowNxSK46nSF8e4bgWO8kptYkOFIRrgpkj9Kdh9SI ykDZt8OS5IdCB5QgwaeEUcPLlA5VO+3ZfWudgHTT/HuCYIXbmhp8jSov1o+JGGkWIA TBklAVupy16hUTLIJ6cmKNG5SwOL6icUk9wshbQY= 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 5.4 05/61] kernel: kexec: remove the lock operation of system_transition_mutex Date: Tue, 2 Feb 2021 14:37:43 +0100 Message-Id: <20210202132946.706162495@linuxfoundation.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210202132946.480479453@linuxfoundation.org> References: <20210202132946.480479453@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@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 @@ -1129,7 +1129,6 @@ int kernel_kexec(void) #ifdef CONFIG_KEXEC_JUMP if (kexec_image->preserve_context) { - lock_system_sleep(); pm_prepare_console(); error = freeze_processes(); if (error) { @@ -1192,7 +1191,6 @@ int kernel_kexec(void) thaw_processes(); Restore_console: pm_restore_console(); - unlock_system_sleep(); } #endif