Re: Fix x86 32 bit FRAME_POINTER chasing code

From: Ingo Molnar
Date: Thu Jan 10 2008 - 01:55:08 EST



* Arjan van de Ven <arjan@xxxxxxxxxxxxx> wrote:

> +++ linux-2.6.24-rc7/arch/x86/kernel/traps_32.c
> @@ -124,7 +124,8 @@ static inline unsigned long print_contex
> unsigned long addr;
>
> addr = frame->return_address;
> - ops->address(data, addr);
> + if (__kernel_text_address(addr))
> + ops->address(data, addr);
> /*
> * break out of recursive entries (such as
> * end_of_stack_stop_unwind_function). Also,
> @@ -132,6 +133,7 @@ static inline unsigned long print_contex
> * move downwards!
> */
> next = frame->next_frame;
> + ebp = (unsigned long) next;
> if (next <= frame)

thanks, applied. Nice catch!

> This patch is simple; I don't know if it's .24 candidate; the bug is
> pretty bad but not a recent regression, and there is obviously some
> risk with touching this code.

it's a 2.6.24.1 candidate i believe. We trigger plenty of various
crashes during x86.git maintenance and others hit various crashes in
-mm, so by the time .1 is released we'll have it in .25 and can backport
it. Most folks/distros will update to 2.6.24.1 very quickly so there's
no risk of months loss of quality to kerneloops.org data either.

if there's more than 1-2 weeks to the v2.6.24 release we could merge it
right now as well:

Acked-by: Ingo Molnar <mingo@xxxxxxx>

because in a week we'll trigger plenty of crashes in -git based x86
trees and will know about any regressions and will be able to reasonably
trust it.

Ingo
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