Re: TRACE: config warning for IRQSOFF_TRACER

From: Steven Rostedt
Date: Mon Aug 30 2010 - 20:47:40 EST


On Sat, 2010-08-21 at 15:52 +0100, Richard Kennedy wrote:
> In my config with PROVE_LOCKING=n and FTRACE=y (which defaults
> IRQSOFF_TRACER to y), I get the following warning from make oldconfig.
>
> scripts/kconfig/conf --oldconfig arch/x86/Kconfig
> warning: (IRQSOFF_TRACER && TRACING_SUPPORT && FTRACE &&
> TRACE_IRQFLAGS_SUPPORT && !ARCH_USES_GETTIMEOFFSET) selects
> TRACE_IRQFLAGS which has unmet direct dependencies (DEBUG_KERNEL &&
> TRACE_IRQFLAGS_SUPPORT && PROVE_LOCKING)
>
> The problem is that TRACE_IRQFLAGS depends on PROVE_LOCKING.
> Should it select PROVE_LOCKING instead? or is there a better way to fix
> this?

The TRACE_IRQFLAGS was originally written for lockdep, but it is now
used by Ftrace's irqsoff tracer.

I just compiled and booted with TRACE_IRQFLAGS=y and PROVE_LOCKING not
set, and it worked fine.

I think the correct patch is to remove the dependency of TRACE_IRQFLAGS
on PROVE_LOCKING.

-- Steve


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