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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 4A235C43381 for ; Mon, 4 Mar 2019 00:40:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 146DA20818 for ; Mon, 4 Mar 2019 00:40:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726069AbfCDAkZ (ORCPT ); Sun, 3 Mar 2019 19:40:25 -0500 Received: from mail-pf1-f193.google.com ([209.85.210.193]:41960 "EHLO mail-pf1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725933AbfCDAkZ (ORCPT ); Sun, 3 Mar 2019 19:40:25 -0500 Received: by mail-pf1-f193.google.com with SMTP id d25so1684567pfn.8; Sun, 03 Mar 2019 16:40:24 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=fnnW4dzsi/HmL27atcBKqhY87XBJda1rWjdELP8bgSY=; b=QLOdYQccutp1zw0T7UK1GIs+1d6JOyGj+o+9P7bNo+JD7RtSskIiHlXfk9TyQrQGd7 ZQptTGT+Z26WZh/LFbp1ltF6anJ5vifn7w+oKuHxP4Ehpvl7oGpCmsU+kI+rc/9QtXoQ KFY+g/+SFs6ypsUlzWzb6CAWmMKIkwc/fsoLhhGn6B6IhSek/qt6CYatg/kVLijTJstw 91+mWSZbcf5EEcoRQ5cP9BSGzOOgTVLqd9k+yw+HH4b0CpJx34+mRvew0NTzNjRPaO6v FPjWeKKZSbSm880JNb9JJp/PGh9zBjKfmbVbawvgPy8Vs6UBYWsmHnWFwVHjws+vzDdT 79Xw== X-Gm-Message-State: APjAAAUKPt2SeLCNlPU05OV1sNZvblJgjoZgiAn+3IguziM3H0p3FGXX Umhv2l+98RGsaRSvZnJgyHJhIFLTAQg= X-Google-Smtp-Source: APXvYqxlMUy0Max0Yj+PtiExdZWZa6Zqpeoqln7YZ3OHZBW6ya9dwocrPiXJXrL50Mp5boQMxIircQ== X-Received: by 2002:a63:4b0a:: with SMTP id y10mr16035974pga.66.1551660023866; Sun, 03 Mar 2019 16:40:23 -0800 (PST) Received: from asus.site ([2601:647:4000:5dd1:a41e:80b4:deb3:fb66]) by smtp.gmail.com with ESMTPSA id b6sm6080638pfo.27.2019.03.03.16.40.22 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 03 Mar 2019 16:40:23 -0800 (PST) Subject: Re: [PATCH] kernel/wq: Fix a alloc_workqueue() error path To: Peter Zijlstra Cc: Ingo Molnar , linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org, syzbot+17335689e239ce135d8b@syzkaller.appspotmail.com, Tejun Heo References: <20190303220046.29448-1-bvanassche@acm.org> From: Bart Van Assche Message-ID: <9c473d9a-fa9b-b432-00d2-48864d070669@acm.org> Date: Sun, 3 Mar 2019 16:40:21 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 MIME-Version: 1.0 In-Reply-To: <20190303220046.29448-1-bvanassche@acm.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org (+Tejun) On 3/3/19 2:00 PM, Bart Van Assche wrote: > This patch fixes a use-after-free and a memory leak in an alloc_workqueue() > error path. This patch avoids that e.g. the following complaint gets > reported: > > BUG: KASAN: use-after-free in __read_once_size include/linux/compiler.h:197 [inline] > BUG: KASAN: use-after-free in lockdep_register_key+0x3b9/0x490 kernel/locking/lockdep.c:1023 > Read of size 8 at addr ffff888090fc2698 by task syz-executor134/7858 > > CPU: 1 PID: 7858 Comm: syz-executor134 Not tainted 5.0.0-rc8-next-20190301 #1 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:77 [inline] > dump_stack+0x172/0x1f0 lib/dump_stack.c:113 > print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187 > kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317 > __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132 > __read_once_size include/linux/compiler.h:197 [inline] > lockdep_register_key+0x3b9/0x490 kernel/locking/lockdep.c:1023 > wq_init_lockdep kernel/workqueue.c:3444 [inline] > alloc_workqueue+0x427/0xe70 kernel/workqueue.c:4263 > ucma_open+0x76/0x290 drivers/infiniband/core/ucma.c:1732 > misc_open+0x398/0x4c0 drivers/char/misc.c:141 > chrdev_open+0x247/0x6b0 fs/char_dev.c:417 > do_dentry_open+0x488/0x1160 fs/open.c:771 > vfs_open+0xa0/0xd0 fs/open.c:880 > do_last fs/namei.c:3416 [inline] > path_openat+0x10e9/0x46e0 fs/namei.c:3533 > do_filp_open+0x1a1/0x280 fs/namei.c:3563 > do_sys_open+0x3fe/0x5d0 fs/open.c:1063 > __do_sys_openat fs/open.c:1090 [inline] > __se_sys_openat fs/open.c:1084 [inline] > __x64_sys_openat+0x9d/0x100 fs/open.c:1084 > do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > Allocated by task 7789: > save_stack+0x45/0xd0 mm/kasan/common.c:75 > set_track mm/kasan/common.c:87 [inline] > __kasan_kmalloc mm/kasan/common.c:497 [inline] > __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:470 > kasan_kmalloc+0x9/0x10 mm/kasan/common.c:511 > __do_kmalloc mm/slab.c:3726 [inline] > __kmalloc+0x15c/0x740 mm/slab.c:3735 > kmalloc include/linux/slab.h:553 [inline] > kzalloc include/linux/slab.h:743 [inline] > alloc_workqueue+0x13c/0xe70 kernel/workqueue.c:4236 > ucma_open+0x76/0x290 drivers/infiniband/core/ucma.c:1732 > misc_open+0x398/0x4c0 drivers/char/misc.c:141 > chrdev_open+0x247/0x6b0 fs/char_dev.c:417 > do_dentry_open+0x488/0x1160 fs/open.c:771 > vfs_open+0xa0/0xd0 fs/open.c:880 > do_last fs/namei.c:3416 [inline] > path_openat+0x10e9/0x46e0 fs/namei.c:3533 > do_filp_open+0x1a1/0x280 fs/namei.c:3563 > do_sys_open+0x3fe/0x5d0 fs/open.c:1063 > __do_sys_openat fs/open.c:1090 [inline] > __se_sys_openat fs/open.c:1084 [inline] > __x64_sys_openat+0x9d/0x100 fs/open.c:1084 > do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > Freed by task 7789: > save_stack+0x45/0xd0 mm/kasan/common.c:75 > set_track mm/kasan/common.c:87 [inline] > __kasan_slab_free+0x102/0x150 mm/kasan/common.c:459 > kasan_slab_free+0xe/0x10 mm/kasan/common.c:467 > __cache_free mm/slab.c:3498 [inline] > kfree+0xcf/0x230 mm/slab.c:3821 > alloc_workqueue+0xc3e/0xe70 kernel/workqueue.c:4295 > ucma_open+0x76/0x290 drivers/infiniband/core/ucma.c:1732 > misc_open+0x398/0x4c0 drivers/char/misc.c:141 > chrdev_open+0x247/0x6b0 fs/char_dev.c:417 > do_dentry_open+0x488/0x1160 fs/open.c:771 > vfs_open+0xa0/0xd0 fs/open.c:880 > do_last fs/namei.c:3416 [inline] > path_openat+0x10e9/0x46e0 fs/namei.c:3533 > do_filp_open+0x1a1/0x280 fs/namei.c:3563 > do_sys_open+0x3fe/0x5d0 fs/open.c:1063 > __do_sys_openat fs/open.c:1090 [inline] > __se_sys_openat fs/open.c:1084 [inline] > __x64_sys_openat+0x9d/0x100 fs/open.c:1084 > do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > The buggy address belongs to the object at ffff888090fc2580 > which belongs to the cache kmalloc-512 of size 512 > The buggy address is located 280 bytes inside of > 512-byte region [ffff888090fc2580, ffff888090fc2780) > > Reported-by: syzbot+17335689e239ce135d8b@syzkaller.appspotmail.com > Fixes: 669de8bda87b ("kernel/workqueue: Use dynamic lockdep keys for workqueues") > Signed-off-by: Bart Van Assche > --- > kernel/workqueue.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/kernel/workqueue.c b/kernel/workqueue.c > index 497900263dbc..35fd0e697087 100644 > --- a/kernel/workqueue.c > +++ b/kernel/workqueue.c > @@ -4291,6 +4291,8 @@ struct workqueue_struct *alloc_workqueue(const char *fmt, > return wq; > > err_free_wq: > + wq_unregister_lockdep(wq); > + wq_free_lockdep(wq); > free_workqueue_attrs(wq->unbound_attrs); > kfree(wq); > return NULL; >