RE: BUG 2.6.7 hangs on boot (rx2600)

Tian, Kevin
2004-06-23T14:26:40Z

On 6/23/2004 6:38AM, Sharma Arun wrote:
>I saw it on a 4 way Tiger as well. The kernel was compiled using the
RHEL3
>toolchain.
>Saw the machine sitting in dispatch_to_fault_handler: with the IIP
pointing to
>count_reserved_pages(). I think IFA was 0.
>
>Didn't get a chance to debug this further.
>
> -Arun

I also saw such hang on Tiger, when rpmbuild on SLES9-RC2. I'm
suspecting that recent patch which moves init_task to region 5 may break
sth there.

Env:
Tiger 4 with 4 Madison
SLES9-RC2 (linux-2.6.5-7.79)

Description:
Before rpmbuild, I applied partial-page patch derived from David's tree,
which happened to contain another patch to move init_task to region 5.
Then when I booted the new kernel created by rpmbuild (so by default
config file), Tiger hangs immediately.

Excluding patch for moving init_task made problem away.
======Kernel just stopped at general_exception(), with IIP pointing to
count_reserved_pages():
IIP: 0xa0000001000594a0 (In count_reserved_pages)
ISR: 0x00000028400000030
IFA: 0xe00000004fefe6018

Then by single step:
General_exception() -> dispatch_to_default_handler() ->
SAVE_MIN_WITH_COVER_R19:
MINSTATE_GET_CURRENT(r16); //r16 = 0xa00000010070c000
(&init_task)
...
adds r16=IA64_TASK_THREAD_ON_USTACK_OFFSET,r16;
\
;;
\
ld1 r17=[r16]; <------Just in this point, ITP also hangs and
seems another fault happening.

I'm suspecting line in ia64_switch_to:
/*
* If we've already mapped this task's page, we can skip doing it
again.
*/
(p6) cmp.eq p7,p6=r27,r27 <----- Should here cmp.eq.unc be used
instead? No time to test it now...

Thanks,
Kevin