Re: [Xen-devel] 100% reliable Oops on xen 4.0.1

[Peter Moody <pmoody@xxxxxxxxxx>]

On Tue, Aug 14, 2012 at 2:19 AM, Ian Campbell <Ian.Campbell@xxxxxxxxxx> wrote:

>>
>>  a) this only happens on our xen machines (though not all of them)
>>  b) one of my stack traces started with
>>
>> [172577.560441]  [<ffffffff810065ad>] ? xen_force_evtchn_callback+0xd/0x10
>
> This is likely to be a coincidence IMHO since this function forces a
> call to the hypervisor to trigger the (re)injection of any pending
> interrupts (typically after reenabling interrupts), so it is not unusual
> for it to be at the bottom of any stack trace which happens in interrupt
> context.
>
> The example stack trace in crasher.c doesn't involve Xen -- can you post
> any examples of ones which do.

Hi Ian, here's the trace in question. I'm perfectly happy with this
not being a xen issue if for no other reason then it means that I have
one less thing I need to look at. The python script in question was
essentially doing the same thing as crasher.c, though in the middle of
other, more productive activities.

Cheers,
peter

------------[ cut here ]------------
kernel BUG at fs/buffer.c:1263!
invalid opcode: 0000 [#1] SMP
last sysfs file: /sys/devices/system/cpu/online
CPU 3
Pid: 27277, comm: python2.6 Not tainted 2.6.38.8-gg868-ganetixenu #1
RIP: e030:[<ffffffff81153853>]  [<ffffffff81153853>]
__find_get_block+0x1f3/0x200
RSP: e02b:ffff880496cffc78  EFLAGS: 00010046
RAX: ffff8807b9480000 RBX: ffff88049f172de8 RCX: 000000000086dafd
RDX: 0000000000001000 RSI: 000000000086dafd RDI: ffff8807ba4dd380
RBP: ffff880496cffcd8 R08: 0000000000000001 R09: ffff88049f172d10
R10: 0000000000000000 R11: 0000000000000000 R12: ffff88049f172d14
R13: ffff88049f172d40 R14: ffff8807ba4b7228 R15: 000000000086dafd
FS:  00007f667a0ca700(0000) GS:ffff8807fff74000(0063) knlGS:0000000000000000
CS:  e033 DS: 002b ES: 002b CR0: 000000008005003b
CR2: 000000000a130260 CR3: 00000004e978c000 CR4: 0000000000002660
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process python2.6 (pid: 27277, threadinfo ffff880496cfe000, task
ffff8804b5a72d40)
Stack:
 ffff880496cffc98 ffffffff81654cd1 ffff880496cffca8 ffff88062d8d2440
 ffff880496cffd08 ffffffff811c9294 ffff8804ffffffc3 0000000000000014
 ffff88049f172de8 ffff88049f172d14 ffff88049f172d40 ffff8807ba4b7228
Call Trace:
 [<ffffffff81654cd1>] ? down_read+0x11/0x30
 [<ffffffff811c9294>] ? ext3_xattr_get+0xf4/0x2b0
 [<ffffffff811baf88>] ext3_clear_blocks+0x128/0x190
 [<ffffffff811bb104>] ext3_free_data+0x114/0x160
 [<ffffffff811bbc0a>] ext3_truncate+0x87a/0x950
 [<ffffffff812133f5>] ? journal_start+0xb5/0x100
 [<ffffffff811bc840>] ext3_evict_inode+0x180/0x1a0
 [<ffffffff8114065f>] evict+0x1f/0xb0
 [<ffffffff81006d52>] ? check_events+0x12/0x20
 [<ffffffff81140c14>] iput+0x1a4/0x290
 [<ffffffff8113ed05>] dput+0x265/0x310
 [<ffffffff81132435>] path_put+0x15/0x30
 [<ffffffff810a5d31>] audit_syscall_exit+0x171/0x260
 [<ffffffff8103ed9a>] sysexit_audit+0x21/0x5f
 [<ffffffff810065ad>] ? xen_force_evtchn_callback+0xd/0x10
 [<ffffffff81006d52>] ? check_events+0x12/0x20
Code: 82 00 05 01 00 85 c0 75 de 65 48 89 1c 25 00 05 01 00 e9 87 fe
ff ff 48 89 df e8 e9 fc ff ff 4c 89 f7 e9 02 ff ff ff 0f 0b eb fe <0f>
0b eb fe 0f 0b eb fe 0f 1f 44 00 00 55 48 89 e5 41 57 49 89
RIP  [<ffffffff81153853>] __find_get_block+0x1f3/0x200
 RSP <ffff880496cffc78>
---[ end trace d45267c89c4e0548 ]---


-- 
Peter Moody      Google    1.650.253.7306
Security Engineer  pgp:0xC3410038

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