linux-kernel - Re: [PATCH 0/9] traps: x86: finalize unification of traps.c

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Date:	Sat, 4 Oct 2008 11:27:45 +0200
From:	Ingo Molnar <mingo@...e.hu>
To:	Alexander van Heukelum <heukelum@...tmail.fm>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	"H. Peter Anvin" <hpa@...or.com>, Yinghai Lu <yinghai@...nel.org>,
	Jeremy Fitzhardinge <jeremy@...p.org>
Subject: Re: [PATCH 0/9] traps: x86: finalize unification of traps.c


* Ingo Molnar <mingo@...e.hu> wrote:

> 
> * Alexander van Heukelum <heukelum@...tmail.fm> wrote:
> 
> > Hi Ingo,
> > 
> > This series unifies traps_32.c and traps_64.c.
> 
> wow, very nice! I've applied them to tip/x86/traps:
> 
> f58f3d5: traps: x86: finalize unification of traps.c
> bf395d6: traps: x86: make traps_32.c and traps_64.c equal
> f156f35: traps: x86: various noop-changes preparing for unification of traps_xx.c
> 70cfe30: traps: x86_64: use task_pid_nr(tsk) instead of tsk->pid in do_general_protection
> dc89ce0: traps: i386: expand clear_mem_error and remove from mach_traps.h
> 6f8063f: traps: x86_64: make io_check_error equal to the one on i386
> d025445: traps: i386: use preempt_conditional_sti/cli in do_int3
> 2180afa: traps: x86_64: make math_state_restore more like i386
> 686cc4a: traps: x86: converge trap_init functions

-tip testing found a spontaneus reboot bug on two 32-bit systems (one 
Intel and one AMD testbox), and i've bisected it down to:

| 686cc4a0c1ca92bffbc22a897c3b433dadbbf444 is first bad commit
| commit 686cc4a0c1ca92bffbc22a897c3b433dadbbf444
| Author: Alexander van Heukelum <heukelum@...tmail.fm>
| Date:   Fri Oct 3 22:00:32 2008 +0200
|
|     traps: x86: converge trap_init functions

config attached. The bisection log:

 # bad:  [a229a9da] Merge branch 'timers/urgent'
 # good: [27de5e39] Merge branch 'out-of-tree'
 # good: [8e9cb9db] Merge branch 'tracing/ring-buffer'
 # bad:  [70cfe30f] traps: x86_64: use task_pid_nr(tsk) instead of tsk
 # bad:  [d0254456] traps: i386: use preempt_conditional_sti/cli in do
 # bad:  [2180afaf] traps: x86_64: make math_state_restore more like i
 # bad:  [686cc4a0] traps: x86: converge trap_init functions

so i've excluded these commits from tip/master for now.

there's no serial log entry visible - the spontaneous reboot happens at 
around when we hit user-space.

I suspect syscall entry setup might be borked - the stack frames of call 
gates versus interrupt gates are different and it's easy to make a small 
mistake there with such effects.

	Ingo

View attachment "config-Sat_Oct__4_10_50_26_CEST_2008.bad" of type "text/plain" (63403 bytes)