Attachment 314376 Details for Bug 458500 – Fix lockdep irq tracing bug on powerpc

Fix lockdep irq tracing bug on powerpc

powerpc-lockdep-problem.diff (text/plain), 1.25 KB, created by IBM Bug Proxy on 2008-08-15 07:20:39 UTC

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Creator: IBM Bug Proxy

Created: 2008-08-15 07:20:39 UTC

Size: 1.25 KB

patch

obsolete

>powerpc: Fix lockdep IRQ tracing bug
>
>A small bogon sneaked into the ppc64 lockdep support. A test is
>branching slightly off causing a clobbered register value to
>overwrite the irq state under some circumstances.
>
>Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
>---
>
>This explains some of the reported weird lockdep errors, maybe
>even all of them, we'll see.
>
>We should probably backport that to 2.6.26-stable too, any candidate ?
>
>Index: linux-work/arch/powerpc/include/asm/irqflags.h
>===================================================================
>--- linux-work.orig/arch/powerpc/include/asm/irqflags.h	2008-08-15 16:48:43.000000000 +1000
>+++ linux-work/arch/powerpc/include/asm/irqflags.h	2008-08-15 16:51:02.000000000 +1000
>@@ -20,7 +20,7 @@
> #define TRACE_ENABLE_INTS	bl .trace_hardirqs_on
> #define TRACE_DISABLE_INTS	bl .trace_hardirqs_off
> #define TRACE_AND_RESTORE_IRQ_PARTIAL(en,skip)	\
>-	cmpdi	en, 0;				\
>+	cmpdi	en,0;				\
> 	bne	95f;				\
> 	stb	en,PACASOFTIRQEN(r13);		\
> 	bl	.trace_hardirqs_off;		\
>@@ -29,7 +29,8 @@
> 	li	en,1;
> #define TRACE_AND_RESTORE_IRQ(en)		\
> 	TRACE_AND_RESTORE_IRQ_PARTIAL(en,96f);	\
>-96:	stb	en,PACASOFTIRQEN(r13)
>+	stb	en,PACASOFTIRQEN(r13);	        \
>+96:
> #else
> #define TRACE_ENABLE_INTS
> #define TRACE_DISABLE_INTS

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