From patchwork Thu Mar 2 15:45:40 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michal Hocko X-Patchwork-Id: 9600585 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id E3E2960453 for ; Thu, 2 Mar 2017 15:48:36 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D239B285BB for ; Thu, 2 Mar 2017 15:48:36 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id C61F6285BA; Thu, 2 Mar 2017 15:48:36 +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=-6.4 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RCVD_IN_SORBS_SPAM 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 67017285B5 for ; Thu, 2 Mar 2017 15:48:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754014AbdCBPsa (ORCPT ); Thu, 2 Mar 2017 10:48:30 -0500 Received: from mail-wr0-f196.google.com ([209.85.128.196]:36525 "EHLO mail-wr0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751585AbdCBPqj (ORCPT ); Thu, 2 Mar 2017 10:46:39 -0500 Received: by mail-wr0-f196.google.com with SMTP id l37so9992877wrc.3; Thu, 02 Mar 2017 07:45:51 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=4wyAfRBG+zu6am/RfQGedMXQzGlmcn5DRm8N7FzRjBo=; b=i2p7GH4JtNNYqAYwmkV9o9UpIPkTEc8TgPaAhEYP4iuIaLO+7qVCr3IFzygenotns9 bkFSBo/vJUXT53yGYNhWCQ9C795RJ6SBr4rIKrJV+9+JBTM1YDS4VVfLl3LUaD1PGDIj mT4ASibsW1dsCAblhqRwK2ZKbsUv5ZAjei04ReGqn4EWZOlVZURL/k7+Q4U5uET67NHu OkpQ05h27I5Y1rth22te+4xOxKxnNkb3oXFsjue1DGd6h1kLDwazlEYxdXAZX4CG9J/+ lHLmaTGrNAVuK/59KIvVXYKbMki75pQFEGaFJ0thUGjX7qaV6R3+YOqwPfo5I/CUSTJ7 xl5g== X-Gm-Message-State: AMke39kyEA3P3/ZSOgn21VvvAQE1GfWJ0L8PSz1nGhJbxQHeAu/Do3nZcwddkGJkLAYpSA== X-Received: by 10.223.170.3 with SMTP id p3mr14325348wrd.100.1488469551076; Thu, 02 Mar 2017 07:45:51 -0800 (PST) Received: from tiehlicka.suse.cz (prg-ext-pat.suse.com. [213.151.95.130]) by smtp.gmail.com with ESMTPSA id 10sm27598907wmi.23.2017.03.02.07.45.49 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 02 Mar 2017 07:45:49 -0800 (PST) From: Michal Hocko To: Christoph Hellwig , Brian Foster Cc: Tetsuo Handa , Xiong Zhou , linux-xfs@vger.kernel.org, , LKML , , Michal Hocko Subject: [PATCH 1/2] xfs: allow kmem_zalloc_greedy to fail Date: Thu, 2 Mar 2017 16:45:40 +0100 Message-Id: <20170302154541.16155-1-mhocko@kernel.org> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20170302153002.GG3213@bfoster.bfoster> References: <20170302153002.GG3213@bfoster.bfoster> Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Michal Hocko Even though kmem_zalloc_greedy is documented it might fail the current code doesn't really implement this properly and loops on the smallest allowed size for ever. This is a problem because vzalloc might fail permanently - we might run out of vmalloc space or since 5d17a73a2ebe ("vmalloc: back off when the current task is killed") when the current task is killed. The later one makes the failure scenario much more probable than it used to be because it makes vmalloc() failures permanent for tasks with fatal signals pending.. Fix this by bailing out if the minimum size request failed. This has been noticed by a hung generic/269 xfstest by Xiong Zhou. fsstress: vmalloc: allocation failure, allocated 12288 of 20480 bytes, mode:0x14080c2(GFP_KERNEL|__GFP_HIGHMEM|__GFP_ZERO), nodemask=(null) fsstress cpuset=/ mems_allowed=0-1 CPU: 1 PID: 23460 Comm: fsstress Not tainted 4.10.0-master-45554b2+ #21 Hardware name: HP ProLiant DL380 Gen9/ProLiant DL380 Gen9, BIOS P89 10/05/2016 Call Trace: dump_stack+0x63/0x87 warn_alloc+0x114/0x1c0 ? alloc_pages_current+0x88/0x120 __vmalloc_node_range+0x250/0x2a0 ? kmem_zalloc_greedy+0x2b/0x40 [xfs] ? free_hot_cold_page+0x21f/0x280 vzalloc+0x54/0x60 ? kmem_zalloc_greedy+0x2b/0x40 [xfs] kmem_zalloc_greedy+0x2b/0x40 [xfs] xfs_bulkstat+0x11b/0x730 [xfs] ? xfs_bulkstat_one_int+0x340/0x340 [xfs] ? selinux_capable+0x20/0x30 ? security_capable+0x48/0x60 xfs_ioc_bulkstat+0xe4/0x190 [xfs] xfs_file_ioctl+0x9dd/0xad0 [xfs] ? do_filp_open+0xa5/0x100 do_vfs_ioctl+0xa7/0x5e0 SyS_ioctl+0x79/0x90 do_syscall_64+0x67/0x180 entry_SYSCALL64_slow_path+0x25/0x25 fsstress keeps looping inside kmem_zalloc_greedy without any way out because vmalloc keeps failing due to fatal_signal_pending. Reported-by: Xiong Zhou Analyzed-by: Tetsuo Handa Signed-off-by: Michal Hocko Reviewed-by: Christoph Hellwig Reviewed-by: Brian Foster Reviewed-by: Darrick J. Wong --- fs/xfs/kmem.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/xfs/kmem.c b/fs/xfs/kmem.c index 339c696bbc01..ee95f5c6db45 100644 --- a/fs/xfs/kmem.c +++ b/fs/xfs/kmem.c @@ -34,6 +34,8 @@ kmem_zalloc_greedy(size_t *size, size_t minsize, size_t maxsize) size_t kmsize = maxsize; while (!(ptr = vzalloc(kmsize))) { + if (kmsize == minsize) + break; if ((kmsize >>= 1) <= minsize) kmsize = minsize; }