From patchwork Sun Jul 10 02:25:47 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tetsuo Handa X-Patchwork-Id: 589684 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 3785BC43334 for ; Sun, 10 Jul 2022 02:26:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229562AbiGJC0L (ORCPT ); Sat, 9 Jul 2022 22:26:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34636 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229545AbiGJC0L (ORCPT ); Sat, 9 Jul 2022 22:26:11 -0400 Received: from www262.sakura.ne.jp (www262.sakura.ne.jp [202.181.97.72]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2AFA9B859 for ; Sat, 9 Jul 2022 19:26:10 -0700 (PDT) Received: from fsav118.sakura.ne.jp (fsav118.sakura.ne.jp [27.133.134.245]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id 26A2Pp8d088449; Sun, 10 Jul 2022 11:25:51 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav118.sakura.ne.jp (F-Secure/fsigk_smtp/550/fsav118.sakura.ne.jp); Sun, 10 Jul 2022 11:25:51 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/fsav118.sakura.ne.jp) Received: from [192.168.1.9] (M106072142033.v4.enabler.ne.jp [106.72.142.33]) (authenticated bits=0) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTPSA id 26A2PpbT088446 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NO); Sun, 10 Jul 2022 11:25:51 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Message-ID: <273ec8c8-8b70-0a0e-4688-5b943ac8e648@I-love.SAKURA.ne.jp> Date: Sun, 10 Jul 2022 11:25:47 +0900 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.11.0 Subject: [PATCH v2 4/4] PM: hibernate: don't set PF_FREEZER_SKIP flag when manipulating /dev/snapshot Content-Language: en-US From: Tetsuo Handa To: Greg KH , Oliver Neukum , Wedson Almeida Filho , "Rafael J. Wysocki" , Arjan van de Ven , Len Brown , Dmitry Vyukov Cc: linux-pm@vger.kernel.org, LKML References: <03096156-3478-db03-c015-28643479116c@I-love.SAKURA.ne.jp> <48d01ce7-e028-c103-ea7f-5a4ea4c8930b@I-love.SAKURA.ne.jp> <2646e8a3-cc9f-c2c5-e4d6-c86de6e1b739@I-love.SAKURA.ne.jp> In-Reply-To: <2646e8a3-cc9f-c2c5-e4d6-c86de6e1b739@I-love.SAKURA.ne.jp> Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org Since khungtaskd skips threads with PF_FREEZER_SKIP flag set, currently we can't report unbounded uninterruptible sleep when something went wrong while manipulating /dev/snapshot interface. Let's change snapshot_{open,read,write}() to use mutex_lock_killable() and change snapshot_release() to use mutex_lock(), so that khungtaskd can report unbounded uninterruptible sleep, by not setting PF_FREEZER_SKIP flag. Since /dev/snapshot is exclusive due to hibernate_acquire(), we could choose mutex_trylock() for snapshot_{open,read,write}() as with snapshot_ioctl(). But until we confirm that this patch does not break something, let's stay mutex_lock_killable(). Signed-off-by: Tetsuo Handa Cc: "Rafael J. Wysocki" Cc: Len Brown Cc: Pavel Machek --- This patch is only compile tested. Need to review if somewhere depends on PF_FREEZER_SKIP flag being set. kernel/power/user.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) diff --git a/kernel/power/user.c b/kernel/power/user.c index 32dd5a855e8c..9936efa07022 100644 --- a/kernel/power/user.c +++ b/kernel/power/user.c @@ -68,7 +68,8 @@ static int snapshot_open(struct inode *inode, struct file *filp) break; } - lock_system_sleep(); + if (mutex_lock_killable(&system_transition_mutex)) + return -EINTR; if (!hibernate_acquire()) { error = -EBUSY; @@ -102,7 +103,7 @@ static int snapshot_open(struct inode *inode, struct file *filp) data->dev = 0; Unlock: - unlock_system_sleep(); + mutex_unlock(&system_transition_mutex); return error; } @@ -111,7 +112,7 @@ static int snapshot_release(struct inode *inode, struct file *filp) { struct snapshot_data *data; - lock_system_sleep(); + mutex_lock(&system_transition_mutex); swsusp_free(); data = filp->private_data; @@ -128,7 +129,7 @@ static int snapshot_release(struct inode *inode, struct file *filp) PM_POST_HIBERNATION : PM_POST_RESTORE); hibernate_release(); - unlock_system_sleep(); + mutex_unlock(&system_transition_mutex); return 0; } @@ -140,7 +141,8 @@ static ssize_t snapshot_read(struct file *filp, char __user *buf, ssize_t res; loff_t pg_offp = *offp & ~PAGE_MASK; - lock_system_sleep(); + if (mutex_lock_killable(&system_transition_mutex)) + return -EINTR; data = filp->private_data; if (!data->ready) { @@ -161,7 +163,7 @@ static ssize_t snapshot_read(struct file *filp, char __user *buf, *offp += res; Unlock: - unlock_system_sleep(); + mutex_unlock(&system_transition_mutex); return res; } @@ -173,7 +175,8 @@ static ssize_t snapshot_write(struct file *filp, const char __user *buf, ssize_t res; loff_t pg_offp = *offp & ~PAGE_MASK; - lock_system_sleep(); + if (mutex_lock_killable(&system_transition_mutex)) + return -EINTR; data = filp->private_data; @@ -195,7 +198,7 @@ static ssize_t snapshot_write(struct file *filp, const char __user *buf, if (res > 0) *offp += res; unlock: - unlock_system_sleep(); + mutex_unlock(&system_transition_mutex); return res; }