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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,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 57146C43441 for ; Fri, 9 Nov 2018 08:38:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1B31620883 for ; Fri, 9 Nov 2018 08:38:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1B31620883 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lge.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727667AbeKISRd (ORCPT ); Fri, 9 Nov 2018 13:17:33 -0500 Received: from lgeamrelo12.lge.com ([156.147.23.52]:48572 "EHLO lgeamrelo11.lge.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727366AbeKISRd (ORCPT ); Fri, 9 Nov 2018 13:17:33 -0500 Received: from unknown (HELO lgeamrelo04.lge.com) (156.147.1.127) by 156.147.23.52 with ESMTP; 9 Nov 2018 17:37:59 +0900 X-Original-SENDERIP: 156.147.1.127 X-Original-MAILFROM: chanho.min@lge.com Received: from unknown (HELO kernel.lge.com) (165.186.175.97) by 156.147.1.127 with ESMTP; 9 Nov 2018 17:37:59 +0900 X-Original-SENDERIP: 165.186.175.97 X-Original-MAILFROM: chanho.min@lge.com From: Chanho Min To: "Rafael J. Wysocki" , Pavel Machek , Len Brown , Andrew Morton , "Eric W. Biederman" , Christian Brauner , Oleg Nesterov , Anna-Maria Gleixner , Alexander Viro Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Seungho Park , Inkyu Hwang , Donghwan Jung , Jongsung Kim , Chanho Min Subject: [PATCH] exec: make de_thread() freezable Date: Fri, 9 Nov 2018 17:37:36 +0900 Message-Id: <1541752656-12857-1-git-send-email-chanho.min@lge.com> X-Mailer: git-send-email 2.1.4 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Suspend fails due to the exec family of functions blocking the freezer. The casue is that de_thread() sleeps in TASK_UNINTERRUPTIBLE waiting for all sub-threads to die, and we have the deadlock if one of them is frozen. In our machine, it causes freeze timeout as bellows. Freezing of tasks failed after 20.010 seconds (1 tasks refusing to freeze, wq_busy=0): setcpushares-ls D ffffffc00008ed70 0 5817 1483 0x0040000d Call trace: [] __switch_to+0x88/0xa0 [] __schedule+0x1bc/0x720 [] schedule+0x40/0xa8 [] flush_old_exec+0xdc/0x640 [] load_elf_binary+0x2a8/0x1090 [] search_binary_handler+0x9c/0x240 [] load_script+0x20c/0x228 [] search_binary_handler+0x9c/0x240 [] do_execveat_common.isra.14+0x4f8/0x6e8 [] compat_SyS_execve+0x38/0x48 [] el0_svc_naked+0x24/0x28 To fix this, make de_thread() freezable. It looks safe and works fine. Suggested-by: Oleg Nesterov Signed-off-by: Chanho Min --- fs/exec.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/exec.c b/fs/exec.c index 1ebf6e5..70ccfc8 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -62,6 +62,7 @@ #include #include #include +#include #include #include @@ -1083,7 +1084,7 @@ static int de_thread(struct task_struct *tsk) while (sig->notify_count) { __set_current_state(TASK_KILLABLE); spin_unlock_irq(lock); - schedule(); + freezable_schedule(); if (unlikely(__fatal_signal_pending(tsk))) goto killed; spin_lock_irq(lock); -- 2.1.4