Re: bad page when freeing preallocated pages

[Hans-Christian Egtvedt <hcegtvedt@norway.atmel.com>]

Takashi Iwai wrote:
> At Wed, 26 Apr 2006 10:30:30 +0200,
> Hans-Christian Egtvedt wrote:

<snip>

>> Example:
>> [  141.380000] Bad page state in process 'rmmod'
>> [17179650.992000] page:90200600 flags:0x00004000 mapping:00000000
>> mapcount:0 count:0
>>
>> Sorry if my email is lacking information, I'll gladly provide more
>> information.
> 
> It's a new bug I haven't seen yet.
> 
> Could you give more detail on your system - the architecture, the
> linux kernel version, and the ALSA version?

~ # uname -a
Linux (none) 2.6.16.11 #3 Wed Apr 26 11:21:06 CEST 2006 avr32 unknown

~ # cat /proc/asound/version
Advanced Linux Sound Architecture Driver Version 1.0.11rc2 (Wed Jan 04
08:57:20 2006 UTC).

The architecture is the AVR32 processor family from Atmel running on the
ATSTK1000 development board.

The interessting part is that if I preallocate a small area (4kB), then
the bad pages go away on rmmod. It could maybe be that we have some
undiscovered bug in dma_alloc_coherent() or dma_free_coherent(), but we
use there function calls in other drivers, so i doubt it (but keeping
the option open;) ).

-- 
With kind regards,
Med vennlig hilsen,

Hans-Christian Egtvedt
Applications Engineer - AVR Applications Lab
Atmel Norway


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