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SubjectRe: Oops in trace_hardirqs_on (powerpc)
Hi Steven,

Steven Rostedt hat am Wed 22. Dec, 21:42 (-0500) geschrieben:
> On Sun, 2010-12-19 at 14:27 +0100, Jörg Sommer wrote:
> > Did you've fixed this problem? The bug report is still marked as open.
> > https://bugzilla.kernel.org/show_bug.cgi?id=16573
> >
>
> I just posted a patch to that BZ. I have it here below too. Could you
> see if it fixes you problem. I only fixed the one place that you
> reported, it may need more fixes (and in that case a macro to do the
> work).
>
> I hit the same bug on my ppc64 box, and have a fix for that, that I'll
> post to LKML tomorrow.
>
> -- Steve
>
> diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
> index ed4aeb9..915cc03 100644
> --- a/arch/powerpc/kernel/entry_32.S
> +++ b/arch/powerpc/kernel/entry_32.S
> @@ -879,7 +879,18 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_TYPE_47x)
> */
> andi. r10,r9,MSR_EE
> beq 1f
> + /*
> + * Since the ftrace irqsoff latency trace checks CALLER_ADDR1,
> + * which is the stack frame here, we need to force a stack frame
> + * in case we came from user space.
> + */
> + stwu r1,-32(r1)
> + mflr r0
> + stw r0,4(r1)
> + stwu r1,-32(r1)
> bl trace_hardirqs_on
> + lwz r1,0(r1)
> + lwz r1,0(r1)
> lwz r9,_MSR(r1)
> 1:
> #endif /* CONFIG_TRACE_IRQFLAGS */

This patch eliminates the oopses.

Bye, Jörg.
--
Der Klügere gibt so lange nach bis er der Dumme ist.
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