From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:48315 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750932AbaBNBeB (ORCPT ); Thu, 13 Feb 2014 20:34:01 -0500 Received: from m3.gw.fujitsu.co.jp (unknown [10.0.50.73]) by fgwmail6.fujitsu.co.jp (Postfix) with ESMTP id 0A3843EE0BC for ; Fri, 14 Feb 2014 10:34:00 +0900 (JST) Received: from smail (m3 [127.0.0.1]) by outgoing.m3.gw.fujitsu.co.jp (Postfix) with ESMTP id EF60945DEB7 for ; Fri, 14 Feb 2014 10:33:59 +0900 (JST) Received: from s3.gw.fujitsu.co.jp (s3.gw.nic.fujitsu.com [10.0.50.93]) by m3.gw.fujitsu.co.jp (Postfix) with ESMTP id D843C45DD76 for ; Fri, 14 Feb 2014 10:33:59 +0900 (JST) Received: from s3.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id CADBA1DB803E for ; Fri, 14 Feb 2014 10:33:59 +0900 (JST) Received: from m1001.s.css.fujitsu.com (m1001.s.css.fujitsu.com [10.240.81.139]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id 76BF21DB803B for ; Fri, 14 Feb 2014 10:33:59 +0900 (JST) Message-ID: <52FD726B.2080503@jp.fujitsu.com> Date: Fri, 14 Feb 2014 10:33:31 +0900 From: Hidetoshi Seto MIME-Version: 1.0 To: linux-btrfs@vger.kernel.org CC: Anand Jain , clm@fb.com Subject: Re: [RFC PATCH] btrfs: fix null pointer deference at btrfs_sysfs_add_one+0x105 References: <1389777748-4341-1-git-send-email-Anand.Jain@oracle.com> In-Reply-To: <1389777748-4341-1-git-send-email-Anand.Jain@oracle.com> Content-Type: text/plain; charset=ISO-2022-JP Sender: linux-btrfs-owner@vger.kernel.org List-ID: I still see this trouble on v3.14-rc2. I confirmed that we cannot do mount with -o degraded without this patch. Could you pick this up, Chris? Thanks, H.Seto Feel free to add: Tested-by: Hidetoshi Seto (2014/01/15 18:22), Anand Jain wrote: > bdev is null when disk has disappeared and mounted with > the degrade option > > stack trace > --------- > btrfs_sysfs_add_one+0x105/0x1c0 [btrfs] > open_ctree+0x15f3/0x1fe0 [btrfs] > btrfs_mount+0x5db/0x790 [btrfs] > ? alloc_pages_current+0xa4/0x160 > mount_fs+0x34/0x1b0 > vfs_kern_mount+0x62/0xf0 > do_mount+0x22e/0xa80 > ? __get_free_pages+0x9/0x40 > ? copy_mount_options+0x31/0x170 > SyS_mount+0x7e/0xc0 > system_call_fastpath+0x16/0x1b > --------- > > reproducer: > ------- > mkfs.btrfs -draid1 -mraid1 /dev/sdc /dev/sdd > (detach a disk) > devmgt detach /dev/sdc [1] > mount -o degrade /dev/sdd /btrfs > ------- > > [1] github.com/anajain/devmgt.git > > Signed-off-by: Anand Jain > --- > fs/btrfs/sysfs.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > > diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c > index ba94b27..f20bc1f 100644 > --- a/fs/btrfs/sysfs.c > +++ b/fs/btrfs/sysfs.c > @@ -578,8 +578,14 @@ static int add_device_membership(struct btrfs_fs_info *fs_info) > return -ENOMEM; > > list_for_each_entry(dev, &fs_devices->devices, dev_list) { > - struct hd_struct *disk = dev->bdev->bd_part; > - struct kobject *disk_kobj = &part_to_dev(disk)->kobj; > + struct hd_struct *disk; > + struct kobject *disk_kobj; > + > + if (!dev->bdev) > + continue; > + > + disk = dev->bdev->bd_part; > + disk_kobj = &part_to_dev(disk)->kobj; > > error = sysfs_create_link(fs_info->device_dir_kobj, > disk_kobj, disk_kobj->name); >