From patchwork Thu Nov 29 05:55:30 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sasha Levin X-Patchwork-Id: 10703937 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 2192E17F0 for ; Thu, 29 Nov 2018 05:59:21 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 14C7E2E6A0 for ; Thu, 29 Nov 2018 05:59:21 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 087942E6A9; Thu, 29 Nov 2018 05:59:21 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4C0A32E6A0 for ; Thu, 29 Nov 2018 05:59:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728783AbeK2RD0 (ORCPT ); Thu, 29 Nov 2018 12:03:26 -0500 Received: from mail.kernel.org ([198.145.29.99]:37600 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727402AbeK2RDZ (ORCPT ); Thu, 29 Nov 2018 12:03:25 -0500 Received: from sasha-vm.mshome.net (unknown [37.142.5.207]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8627321104; Thu, 29 Nov 2018 05:59:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1543471154; bh=e5Nv0J2oHwauCYmFw66YMHAf7Gfp+g+y45/Isxcld2Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CCdORK6UOIIdXfJ0NiD+GnUjouCkuIxO8q0Cj+HUVxLIRgJj8csOgpPnvhVFFtOdb xbJSwW/4FmYlhU1xhxko+UfJu2Elqzkk+iGefSbgcMxqiLf3ahSxp9nUl4i01yZARm +BH9049Ra7qPgQUWhfjSPzeqSWnXnzJnNui8ccb8= From: Sasha Levin To: stable@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Chanho Min , "Rafael J . Wysocki" , Sasha Levin , linux-fsdevel@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 39/68] exec: make de_thread() freezable Date: Thu, 29 Nov 2018 00:55:30 -0500 Message-Id: <20181129055559.159228-39-sashal@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20181129055559.159228-1-sashal@kernel.org> References: <20181129055559.159228-1-sashal@kernel.org> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Chanho Min [ Upstream commit c22397888f1eed98cd59f0a88f2a5f6925f80e15 ] 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. This also can occur with the schedule() waiting for the group thread leader to exit if it 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 Acked-by: Oleg Nesterov Acked-by: Pavel Machek Acked-by: Michal Hocko Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin --- fs/exec.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/fs/exec.c b/fs/exec.c index 1ebf6e5a521d..6da8745857cb 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); @@ -1111,7 +1112,7 @@ static int de_thread(struct task_struct *tsk) __set_current_state(TASK_KILLABLE); write_unlock_irq(&tasklist_lock); cgroup_threadgroup_change_end(tsk); - schedule(); + freezable_schedule(); if (unlikely(__fatal_signal_pending(tsk))) goto killed; }