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 87C89C433FE for ; Fri, 6 May 2022 14:15:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1442166AbiEFOTh (ORCPT ); Fri, 6 May 2022 10:19:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42892 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1442190AbiEFOTe (ORCPT ); Fri, 6 May 2022 10:19:34 -0400 X-Greylist: delayed 210 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Fri, 06 May 2022 07:15:46 PDT Received: from out02.mta.xmission.com (out02.mta.xmission.com [166.70.13.232]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3A10022BC4; Fri, 6 May 2022 07:15:45 -0700 (PDT) Received: from in01.mta.xmission.com ([166.70.13.51]:56272) by out02.mta.xmission.com with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1nmykC-009n4e-Hs; Fri, 06 May 2022 08:15:44 -0600 Received: from ip68-227-174-4.om.om.cox.net ([68.227.174.4]:37210 helo=localhost.localdomain) by in01.mta.xmission.com with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1nmykB-007Cxx-Eb; Fri, 06 May 2022 08:15:44 -0600 From: "Eric W. Biederman" To: linux-arch@vger.kernel.org Cc: Tejun Heo , Peter Zijlstra , Vincent Guittot , Al Viro , Jens Axboe , Thomas Gleixner , Linus Torvalds , linux-kernel@vger.kernel.org, "Eric W. Biederman" Date: Fri, 6 May 2022 09:15:10 -0500 Message-Id: <20220506141512.516114-5-ebiederm@xmission.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <87mtfu4up3.fsf@email.froward.int.ebiederm.org> References: <87mtfu4up3.fsf@email.froward.int.ebiederm.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-XM-SPF: eid=1nmykB-007Cxx-Eb;;;mid=<20220506141512.516114-5-ebiederm@xmission.com>;;;hst=in01.mta.xmission.com;;;ip=68.227.174.4;;;frm=ebiederm@xmission.com;;;spf=softfail X-XM-AID: U2FsdGVkX1+YtAybj6KSom4BKXaqhR+tPpLicoHoVIw= X-SA-Exim-Connect-IP: 68.227.174.4 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: [PATCH 5/7] init: Deal with the init process being a user mode process X-SA-Exim-Version: 4.2.1 (built Sat, 08 Feb 2020 21:53:50 +0000) X-SA-Exim-Scanned: Yes (on in01.mta.xmission.com) Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org It is silly for user_mode_thread to leave PF_KTHREAD set on the resulting task. Update the init process so that it does not care if PF_KTHREAD is set or not. Ensure do_populate_rootfs flushes all delayed fput work by calling task_work_run. In the rare instance that async_schedule_domain calls do_populate_rootfs synchronously it is possible do_populate_rootfs will be called directly from the init process. At which point fput will call "task_work_add(current, ..., TWA_RESUME)". The files on the initramfs need to be completely put before we attempt to exec them (which is before the code enters userspace). So call task_work_run just in case there are any pending fput operations. Signed-off-by: "Eric W. Biederman" --- init/initramfs.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/init/initramfs.c b/init/initramfs.c index 2f3d96dc3db6..41e7857d510d 100644 --- a/init/initramfs.c +++ b/init/initramfs.c @@ -15,6 +15,7 @@ #include #include #include +#include #include static ssize_t __init xwrite(struct file *file, const char *p, size_t count, @@ -703,6 +704,7 @@ static void __init do_populate_rootfs(void *unused, async_cookie_t cookie) initrd_end = 0; flush_delayed_fput(); + task_work_run(); } static ASYNC_DOMAIN_EXCLUSIVE(initramfs_domain); -- 2.35.3