Re: latest -git: BUG at fs/jfs/namei.c:512 assert(ip->i_nlink)

[Vegard Nossum]

On Fri, Jul 18, 2008 at 11:58 PM, Dave Kleikamp
<shaggy@xxxxxxxxxxxxxxxxxx> wrote:
>> You can also have a copy of my scripts if you want to try to reproduce
>> it locally. But I don't mind testing either :-)
>
> Can you please send me a copy.  For some of these, I'd like to get a
> repeatable test case, so I'm not debugging several problems at once.

Hi,

I've updated my scripts to save the bad disk images too, and now I've
hit a repeatable case:

    mount -o loop disk.1 /mnt
    rm -rf /mnt/*

BUG: unable to handle kernel paging request at f4568036
IP: [<c03048e2>] dbAdjTree+0x62/0xd0
*pde = 36b9a163 *pte = 34568160
Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
Pid: 396, comm: jfsCommit Not tainted (2.6.26-05752-g93ded9b #93)
EIP: 0060:[<c03048e2>] EFLAGS: 00010246 CPU: 1
EIP is at dbAdjTree+0x62/0xd0
EAX: 00000000 EBX: 00020015 ECX: 00000004 EDX: 00080054
ESI: f4548010 EDI: 00000000 EBP: f7a37c58 ESP: f7a37c48
 DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
Process jfsCommit (pid: 396, ti=f7a36000 task=f78a9fe0 task.ti=f7a36000)
Stack: 00020015 f4548804 00000001 00000004 f7a37c78 c0304a0d 00000001 f4548010
       f7a37c88 f4548804 00000001 00000022 f7a37cc0 c03065c1 00000246 f569893c
       c1c44ce0 f7a37c98 c017c77e f4548000 f639b950 f4548800 00000000 00000022
Call Trace:
 [<c0304a0d>] ? dbJoin+0xbd/0xe0
 [<c03065c1>] ? dbFreeBits+0xc1/0x320
 [<c017c77e>] ? unlock_page+0x4e/0x60
 [<c03071ad>] ? dbFreeDmap+0x3d/0xd0
 [<c0307c63>] ? dbFree+0x153/0x270
 [<c0315b01>] ? txFreeMap+0x1d1/0x3e0
 [<c01c65ec>] ? __mark_inode_dirty+0x2c/0x180
 [<c02fcf5b>] ? xtTruncate+0xe7b/0x1030
 [<c015c678>] ? __lock_acquire+0x2c8/0x1140
 [<c015c678>] ? __lock_acquire+0x2c8/0x1140
 [<c03b0c18>] ? _raw_spin_unlock+0x68/0x80
 [<c01c6662>] ? __mark_inode_dirty+0xa2/0x180
 [<c02f9c58>] ? jfs_free_zero_link+0x98/0x1b0
 [<c0159fdd>] ? put_lock_stats+0xd/0x30
 [<c02f6f57>] ? jfs_delete_inode+0x77/0x90
 [<c02f6ee0>] ? jfs_delete_inode+0x0/0x90
 [<c01bc1e2>] ? generic_delete_inode+0x62/0xe0
 [<c01bc37d>] ? generic_drop_inode+0x11d/0x170
 [<c01bb297>] ? iput+0x47/0x50
 [<c0315ee5>] ? txUpdateMap+0x1d5/0x2a0
 [<c015a083>] ? lock_release_holdtime+0x83/0x120
 [<c015bd2b>] ? trace_hardirqs_on+0xb/0x10
 [<c0318921>] ? jfs_lazycommit+0xd1/0x2e0
 [<c012f970>] ? default_wake_function+0x0/0x10
 [<c0318850>] ? jfs_lazycommit+0x0/0x2e0
 [<c014bebc>] ? kthread+0x3c/0x70
 [<c014be80>] ? kthread+0x0/0x70
 [<c0104d8b>] ? kernel_thread_helper+0x7/0x1c
 =======================
Code: f0 8d 44 16 12 8b 5d f0 0f b6 48 02 0f b6 78 03 38 48 03 0f b6
40 01 0f 4d cf 38 c1 0f 4c c8 0f b6 44 16 12 38 c1 0f 4c c8 31 ff <38>
4c 1e 11 75 47 eb 54 8d b6 00 00 00 00 8b 55 f0 83 ea 01 83
EIP: [<c03048e2>] dbAdjTree+0x62/0xd0 SS:ESP 0068:f7a37c48
---[ end trace 2d3ec5b787d965f7 ]---

This decodes to fs/jfs/jfs_dmap.c:2831:

                if (tp->dmt_stree[pp] == max)

or

   0:   38 4c 1e 11             cmp    %cl,0x11(%esi,%ebx,1)

It looks like %esi is the "tp" and %ebx is "pp", which would make pp
== 0x00020015.

Earlier, I got a crash in the same function, but a bit higher (with
the same disk image, and with the same commands):

BUG: unable to handle kernel paging request at daf76077
IP: [<c030488e>] dbAdjTree+0xe/0xd0
*pde = 34e11163 *pte = 1af76160
Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC

Pid: 396, comm: jfsCommit Not tainted (2.6.26-05752-g93ded9b #93)
EIP: 0060:[<c030488e>] EFLAGS: 00010206 CPU: 1
EIP is at dbAdjTree+0xe/0xd0
EAX: daef6010 EBX: daef6804 ECX: 00000004 EDX: 00080056
ESI: daef6010 EDI: 00000004 EBP: f79dfc58 ESP: f79dfc48
 DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
Process jfsCommit (pid: 396, ti=f79de000 task=f7336f90 task.ti=f79de000)
Stack: c0185b72 daef6804 00000001 00000004 f79dfc78 c0304a0d 00000001 daef6010
       f79dfc88 daef6804 00000001 00000022 f79dfcc0 c03065c1 00000246 d7731e5c
       c16511a8 f79dfc98 c017c77e daef6000 f386c180 daef6800 00000000 00000022
Call Trace:
 [<c0185b72>] ? activate_page+0x42/0xb0
 [<c0304a0d>] ? dbJoin+0xbd/0xe0

This corresponds to fs/jfs/jfs_dmap.c:2805:

        if (tp->dmt_stree[lp] == newval)

or

   0:   0f be 44 10 11          movsbl 0x11(%eax,%edx,1),%eax

..and here it looks like %eax is the base pointer and %edx the index,
which would make lp == 0x00080056.

The bad disk image can be found at
http://userweb.kernel.org/~vegard/20080722-jfs/ (no private/sensitive
data)

Thanks,


Vegard

-- 
"The animistic metaphor of the bug that maliciously sneaked in while
the programmer was not looking is intellectually dishonest as it
disguises that the error is the programmer's own creation."
	-- E. W. Dijkstra, EWD1036
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