Re: [GIT PULL] time.c - respin

From: Ingo Molnar
Date: Thu Aug 21 2008 - 06:22:51 EST



* Glauber Costa <gcosta@xxxxxxxxxx> wrote:

> Ingo, please pull the latest master git tree from:
>
> git://git.kernel.org/pub/scm/linux/kernel/git/glommer/linux-2.6-x86-integration.git master
>
> into your tree. It solves a bisectability issue, but I can't,
> unfortunately, reproduce the problem you report. So hopefuly you'll
> now be able to bisect your problems to a point we can find out what's
> going on

i've tried it, and -tip testing found a hang on 64-bit x86.

It hangs here:

[ 0.340029] calling tc_filter_init+0x0/0x4c
[ 0.340029] initcall tc_filter_init+0x0/0x4c returned 0 after 0 msecs
[ 0.340029] calling genl_init+0x0/0xd8
[ hard hang ]

it should have continued with:

[ 2.976346] initcall genl_init+0x0/0xd8 returned 0 after 15 msecs
[ 2.982303] calling cipso_v4_init+0x0/0x88
[ ... etc ... ]

i've bisected the hang back to:

0de577d0dd2d1101431d3438d0880fa32a6188d6 is first bad commit
commit 0de577d0dd2d1101431d3438d0880fa32a6188d6
Author: Glauber Costa <gcosta@xxxxxxxxxx>
Date: Fri Jul 11 15:43:19 2008 -0300

x86: use generic intr_init call

Replace apic initialization code with generic intr_init_hook().

Signed-off-by: Glauber Costa <gcosta@xxxxxxxxxx>

the config is at:

http://redhat.com/~mingo/misc/config-Thu_Aug_21_11_14_36_CEST_2008.bad

but the bug is rather obvious:

- apic_intr_init();
-
- if (!acpi_ioapic)
- setup_irq(2, &irq2);
+ intr_init_hook();

why exactly did you remove the cascade IRQ registration? If it remains
unallocated and a driver happens to use it funny things might occur.

Also, the commit log does not declare why it's removed.

Ingo
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