Re: 2.6.9-rc2-mm4 ps hang ?

[Peter Williams]

Andrew Morton wrote:
> Badari Pulavarty <pbadari@xxxxxxxxxx> wrote:
>
> > Here is the full sysrq-t output.
>
>
> What's this guy up to?
>
> db2fmcd       D 0000000000000000     0 11032      1          1373 11031 (NOTLB)
> 00000101b9b9bef8 0000000000000002 0000003700000037 00000101c13608a0 
>        000000010000009f 0000010199649250 0000010199649588 0000000000000000 
>        0000000000000206 ffffffff801353db 
> Call Trace:<ffffffff801353db>{try_to_wake_up+971} <ffffffff80445570>{__down_write+128} 
>        <ffffffff80125e7f>{sys32_mmap+143} <ffffffff80124b01>{ia32_sysret+0} 
>        
>
> Something is seriously screwed up if it's stuck in try_to_wake_up().  Tried
> generating a few extra traces?
>
> Then again, maybe we're missing an up_read() somewhere.  hrm, I'll check.

It's highly^64 unlikely BUT a possible reason for a task getting stuck 
in try_to_wakeup() is the function adjust_sched_timestamp() which is 
part of the ZAPHOD patch.  This could be tested by removing the if-while 
statement from that function and seeing if that fixes things.  Or you 
could just remove the call from try_to_wake_up().

I'll use a more sensible (bounded) mechanism in the next version of ZAPHOD.

Peter
--
Peter Williams                                   pwil3058@xxxxxxxxxxxxxx

"Learning, n. The kind of ignorance distinguishing the studious."
 -- Ambrose Bierce
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