2010-08-21 14:52:17

by Richard Kennedy

Subject: TRACE: config warning for IRQSOFF_TRACER

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?

regards

Richard

2010-08-31 00:47:37

by Steven Rostedt

Subject: Re: TRACE: config warning for IRQSOFF_TRACER

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