Re: [patch] sched-HT-2.6.0-test11-A5

From: Martin J. Bligh
Date: Sun Dec 07 2003 - 12:48:29 EST

>> i've seen a similar crash once on a 2-way (4-way) HT box, so there some
>> startup race going on most likely.
> Im seeing bootup crashes every now and then on a ppc64 box too. A few
> other things Ive noticed:

ALT+sysrq+t does nothing, but NMI watchdog gives me:


Starting migration thread for cpu 0
NMI Watchdog detected LOCKUP on CPU0, eip c011c11b, registers:
CPU: 0
EIP: 0060:[<c011c11b>] Not tainted
EFLAGS: 00000086
EIP is at .text.lock.sched+0xee/0x243
eax: 0000000c ebx: 00000286 ecx: f018a000 edx: c3932bc0
esi: 0000000c edi: c3932bc0 ebp: f018bfb4 esp: f018bfac
ds: 007b es: 007b ss: 0068
Process migration/0 (pid: 2, threadinfo=f018a000 task=f018f330)
Stack: 00000000 00000000 f018bfec c011befe 02000000 00000020 c011bd54 00000000
00000000 f018f330 c0309c60 c0309c60 f018a000 f018a000 00000000 00000063
00000000 c0107001 f01a3fac 00000000 00000000
Call Trace:
[<c011befe>] migration_task+0x1aa/0x1b4
[<c011bd54>] migration_task+0x0/0x1b4
[<c0107001>] kernel_thread_helper+0x5/0xc

Code: 7e f8 e9 44 e6 ff ff f3 90 80 7e 04 00 7e f8 e9 6b e6 ff ff
console shuts up ...


[<c011befe>] migration_task+0x1aa/0x1b4

is just after the return from complete, so I'd say we're deadlocked
on "spin_lock_irqsave(&x->wait.lock, flags);" in complete. Afraid I
don't understand what the completion / migration stuff is attempting
to do, so can't be more help ... I can reproduce this 100% of the
time if you want something tried though.


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