Subject: Re: Random crashes with 2.6.27-rc3 on PPC

From: Andreas Schwab <[email-masked]>
Date: Sun, 24 Aug 2008 16:46:38 +0200

Michael Buesch <[email-masked]> writes:

> The following workaround seems to fix the crashes on powerpc.
> However, this patch is clearly not what we want for other architectures,
> as they might need -fno-omit-frame-pointer to function properly.

This has a better chance to be accepted. :-)

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 8b5a7d3..f9a2e48 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -394,7 +394,7 @@ config LOCKDEP
 	bool
 	depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
 	select STACKTRACE
-	select FRAME_POINTER if !X86 && !MIPS
+	select FRAME_POINTER if !X86 && !MIPS && !PPC
 	select KALLSYMS
 	select KALLSYMS_ALL

> Index: linux-2.6/kernel/Makefile
> ===================================================================
> --- linux-2.6.orig/kernel/Makefile	2008-08-24 11:50:23.000000000 +0200
> +++ linux-2.6/kernel/Makefile	2008-08-24 12:15:54.000000000 +0200
> @@ -92,13 +92,13 @@ obj-$(CONFIG_SMP) += sched_cpupri.o
>  ifneq ($(CONFIG_SCHED_NO_NO_OMIT_FRAME_POINTER),y)
>  # According to Alan Modra <[email-masked]>, the -fno-omit-frame-pointer is
>  # needed for x86 only.  Why this used to be enabled for all architectures is beyond
>  # me.  I suspect most platforms don't need this, but until we know that for sure
>  # I turn this off for IA-64 only.  Andreas Schwab says it's also needed on m68k
>  # to get a correct value for the wait-channel (WCHAN in ps). --davidm
> -CFLAGS_sched.o := $(PROFILING) -fno-omit-frame-pointer
> +CFLAGS_sched.o := $(PROFILING)

CONFIG_SCHED_NO_NO_OMIT_FRAME_POINTER is already enabled on powerpc.

Andreas.

-- 
Andreas Schwab, SuSE Labs, [email-masked]
SuSE Linux Products GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany
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"And now for something completely different."