Re: Dumb question: BKL on reboot ?

[Hannes Reinecke <Hannes.Reinecke@suse.de>]

Andrea Arcangeli wrote:
> On Thu, Aug 21, 2003 at 05:55:49PM +0200, Hannes Reinecke wrote:
> 
>>Andrea Arcangeli wrote:
>>
>>>On Thu, Aug 21, 2003 at 10:05:20AM +0200, Hannes Reinecke wrote:
>>
>>
>>
>>What happened was this:
>>
>>================================================================
>>TASK HAS CPU (0): 0x904000 (kupdated):
>> LOWCORE INFO:
>>  -psw      : 0x400100180000000 0x0000000007aa22
>>  -function : sync_old_buffers+58
>>  -prefix   : 0x009c8000
>>  -cpu timer: 0xfffffa77 0x33465f80
>>  -clock cmp: 0x00b9e503 0x235324f4
>>  -general registers:
>>     0000000000000000 0x000000002e1000
>>     0x0000000007aa22 0x0000000004919e
>>     0x00000000907f28 0x0000000022b428
>>     0000000000000000 0000000000000000
>>     0x00000000224340 0000000000000000
>>     0x00000000970000 0x00000000233b00
>>     0x00000000904000 0x000000001deb60
>>     0x00000000907e78 0x00000000907dd8
>>[ .. ]
>> STACK:
>> 0 kupdate+424 [0x7af4c]
>> 1 arch_kernel_thread+70 [0x18d72]
>>================================================================
>>TASK HAS CPU (1): 0x3318000 (reboot):
>> LOWCORE INFO:
>>  -psw      : 0x700100180000000 0x0000007ffe0d8e
>>  -function : not found in System map
>>  -prefix   : 0x009c2000
>>  -cpu timer: 0xfff79e2d 0x014244c0
>>  -clock cmp: 0x00b9e503 0x3a5d9504
>>  -general registers:
>>     0x00000000000001 0000000000000000
>>     0000000000000000 0000000000000000
>>     0x0000000001f268 0000000000000000
>>     0x00000000000003 0x000000000002c0
>>     0x000000000490f0 0x00000003318000
>>     0x00000000016422 0000000000000000
>>     0x00000000000001 0x000000001da280
>>     0x0000000001f268 0x0000000331bae0
>>[ .. ]
>> STACK:
>> 0 machine_restart_smp+62 [0x1f5f2]
>> 1 machine_restart+48 [0x19884]
>> 2 sys_reboot+306 [0x49222]
>> 3 sysc_noemu+16 [0x16242]
> 
> 
> This can't be the lock_kernel, you see, there's no lock_kernel
> invocation at all in the machine_restart_smp path.

Oh? sys_reboot() does call lock_kernel(). kernel/sys.c:303.

Agreed, this smp_processor_id() == 0 thing is interesting. I'll try you 
suggestion and see how far I'll progress.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke			hare@suse.de
SuSE Linux AG				S390 & zSeries
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