Re: PROBLEM: 3.6.0 kernel BUG at fs/dcache.c:967 during shutdown/ restart

From: Stanislav Kinsbursky
Date: Tue Oct 09 2012 - 04:06:29 EST

09.10.2012 11:54, Jan Kara ÐÐÑÐÑ:
On Mon 08-10-12 17:10:52, Neil Salstrom wrote:
On 10/08/2012 10:14 AM, Jan Kara wrote:
On Sat 06-10-12 10:20:26, Neil Salstrom wrote:
I've not submitted a kernel bug before but I've read the bug
reporting pages. I'll try to do my best and if you need more
information please let me know. Please feel free to cc me on the
answer or if you have questions.

I'm using Linux Mint 13 (64 bit) on AMD hardware with a self
compiled 3.6.0 kernel for my MythTV HTPC.

Kernel version: Linux version 3.6.0 (gcc version 4.6.3
(Ubuntu/Linaro 4.6.3-1ubuntu5) ) #1 SMP Tue Oct 2 15:34:46 PDT 2012

CPU: model name : AMD A6-3500 APU with Radeon(tm) HD Graphics

If you need any other system variables please let me know and I can
get those as well.

Upon shutdown or restart (from either the hard button on the case or
a "sudo shutdown -r now" the system crashes and does not actually
shut down. I can ssh in to the system and a dmesg shows the
following:
There should be a line like:
BUG: Dentry ... still in use (%d) [unmount of %s %s]

just before the oops. Can you please post that one as well? Also I see that
you are using nvidia module which taints the kernel. Can you try
reproducing the issue without the module loaded?

Honza

Here is the full output with no nvidia module. I also have the full
dmeg from start to finish if you would like it.
Thanks for the new report. Since the use count of the problematic dentry
is 1, I guess this is really some bug in rpc_pipefs. Bruce, any idea?


Hi.
Could you, please, give more details about your configuration.
Currently, PipeFS is mounted on SUNRPC module install.
Would be great to understand, what process tries to umount it and when.
Also, do you have NFS mounts on the node, then Pipefs is umounting?
Is systemd is active on your node?
Could you trigger this panic manually?

Honza

[ 237.186167] BUG: Dentry ffff880118772540{i=6e,n=info} still in
use (1) [unmount of rpc_pipefs rpc_pipefs]
[ 237.186179] ------------[ cut here ]------------
[ 237.186181] kernel BUG at fs/dcache.c:967!
[ 237.186182] invalid opcode: 0000 [#1] SMP
[ 237.186185] Modules linked in: nls_utf8 udf crc_itu_t nfsv4
binfmt_misc nfsd nfs_acl auth_rpcgss nfs fscache lockd sunrpc
snd_hda_codec_hdmi snd_hda_codec_realtek xfs snd_hda_intel
snd_hda_codec snd_seq_midi snd_hwdep snd_rawmidi snd_pcm psmouse
snd_seq_midi_event rc_imon_mce serio_raw snd_seq imon rc_core
snd_timer snd_seq_device snd soundcore snd_page_alloc f71882fg r8169
ahci libahci
[ 237.186203] CPU 2
[ 237.186206] Pid: 3063, comm: umount Not tainted 3.6.0 #1 System
manufacturer System Product Name/F1A55-M LX PLUS
[ 237.186208] RIP: 0010:[<ffffffff8116c606>] [<ffffffff8116c606>]
shrink_dcache_for_umount_subtree+0x1e6/0x1f0
[ 237.186214] RSP: 0018:ffff8801181afd98 EFLAGS: 00010296
[ 237.186215] RAX: 000000000000005d RBX: ffff880118772540 RCX:
00000000000014bd
[ 237.186217] RDX: 0000000000003256 RSI: 0000000000000046 RDI:
ffffffff81bbf9bc
[ 237.186218] RBP: ffff8801181afdb8 R08: 000000000000000a R09:
0000000000000000
[ 237.186219] R10: 0000000000000383 R11: 0000000000000382 R12:
ffff88011873b9c0
[ 237.186220] R13: ffff8801177a2b80 R14: ffff8801177a2bb0 R15:
ffff88011287d800
[ 237.186222] FS: 00007f67049b1800(0000) GS:ffff88011ed00000(0000)
knlGS:0000000000000000
[ 237.186223] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 237.186225] CR2: 00007f3e1de80000 CR3: 0000000118a18000 CR4:
00000000000007e0
[ 237.186226] DR0: 0000000000000000 DR1: 0000000000000000 DR2:
0000000000000000
[ 237.186227] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7:
0000000000000400
[ 237.186229] Process umount (pid: 3063, threadinfo
ffff8801181ae000, task ffff880110fbc440)
[ 237.186230] Stack:
[ 237.186231] ffff88011287db50 ffff88011873b780 ffff88011287d800
ffffffffa021d3c0
[ 237.186233] ffff8801181afdd8 ffffffff8116de93 0000000000000001
ffff88011287d800
[ 237.186235] ffff8801181afe08 ffffffff811583bc ffff88011873b820
0000000000000015
[ 237.186238] Call Trace:
[ 237.186241] [<ffffffff8116de93>] shrink_dcache_for_umount+0x33/0x60
[ 237.186244] [<ffffffff811583bc>] generic_shutdown_super+0x2c/0xf0
[ 237.186247] [<ffffffff81158516>] kill_anon_super+0x16/0x30
[ 237.186249] [<ffffffff81158557>] kill_litter_super+0x27/0x30
[ 237.186265] [<ffffffffa02174a9>] rpc_kill_sb+0x99/0xc0 [sunrpc]
[ 237.186268] [<ffffffff8115877c>] deactivate_locked_super+0x3c/0xa0
[ 237.186270] [<ffffffff8115938e>] deactivate_super+0x4e/0x70
[ 237.186273] [<ffffffff81174416>] mntput_no_expire+0x106/0x160
[ 237.186276] [<ffffffff8117543e>] sys_umount+0x6e/0x3b0
[ 237.186279] [<ffffffff81583d96>] system_call_fastpath+0x1a/0x1f
[ 237.186280] Code: 00 00 48 8b 40 28 4c 8b 08 48 8b 43 30 48 85 c0
74 04 48 8b 50 40 48 89 34 24 48 c7 c7 48 69 7c 81 48 89 de 31 c0 e8
09 62 40 00 <0f> 0b 0f 0b 66 0f 1f 44 00 00 55 48 89 e5 41 54 53 66
66 66 66
[ 237.186301] RIP [<ffffffff8116c606>]
shrink_dcache_for_umount_subtree+0x1e6/0x1f0
[ 237.186303] RSP <ffff8801181afd98>
[ 237.186320] ---[ end trace 74629a120592ec3c ]---
[ 238.707925] mtrr: no MTRR for f9000000,e00000 found
[ 245.162939] imon:send_packet: task interrupted
[ 245.218338] nfsd: last server has exited, flushing export cache
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--
Best regards,
Stanislav Kinsbursky
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