From patchwork Thu Nov 29 06:00:54 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sasha Levin X-Patchwork-Id: 10703985 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 BAB3918B8 for ; Thu, 29 Nov 2018 06:09:39 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id AE10E2E663 for ; Thu, 29 Nov 2018 06:09:39 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id A29EF2E67F; Thu, 29 Nov 2018 06:09:39 +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 3EA5D2E663 for ; Thu, 29 Nov 2018 06:09:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729108AbeK2RGm (ORCPT ); Thu, 29 Nov 2018 12:06:42 -0500 Received: from mail.kernel.org ([198.145.29.99]:43208 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729641AbeK2RGl (ORCPT ); Thu, 29 Nov 2018 12:06:41 -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 C6258213A2; Thu, 29 Nov 2018 06:02:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1543471350; bh=q+QxCI+Fxjshjm62J4/HS3sFKLsxZSYLxI+7C+9iChE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Q8dhGcxFK5NODs4iZUCgeNAQ6weYmesqmEt3AANh9mnAAygN+rKCA4xSHTAHV1rem sMTlpX9aNpgXWmBnWRFLtvQtE+m7iR5wY3pfpbKB2AqYodtwvs1YdRHO8bHwL27rUn S1iNIFgkLc81cD6DR6Au/bDQGW7HpiIx7skuC1zM= 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 4.14 20/35] exec: make de_thread() freezable Date: Thu, 29 Nov 2018 01:00:54 -0500 Message-Id: <20181129060110.159878-20-sashal@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20181129060110.159878-1-sashal@kernel.org> References: <20181129060110.159878-1-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 0da4d748b4e6..25c529f46aaa 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -62,6 +62,7 @@ #include #include #include +#include #include #include @@ -1079,7 +1080,7 @@ 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); @@ -1107,7 +1108,7 @@ 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; }