Re: [PATCH] tracing: Fix lockdep warning in global_clock()

From: Ingo Molnar
Date: Mon Dec 21 2009 - 01:44:19 EST



* Li Zefan <lizf@xxxxxxxxxxxxxx> wrote:

> # echo 1 > events/enable
> # echo global > trace_clock
>
> ------------[ cut here ]------------
> WARNING: at kernel/lockdep.c:3162 check_flags+0xb2/0x190()
> ...
> ---[ end trace 3f86734a89416623 ]---
> possible reason: unannotated irqs-on.
> ...
>
> Signed-off-by: Li Zefan <lizf@xxxxxxxxxxxxxx>
> ---
> kernel/trace/trace_clock.c | 4 ++--
> 1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/trace/trace_clock.c b/kernel/trace/trace_clock.c
> index 84a3a7b..11563c9 100644
> --- a/kernel/trace/trace_clock.c
> +++ b/kernel/trace/trace_clock.c
> @@ -83,7 +83,7 @@ u64 notrace trace_clock_global(void)
> int this_cpu;
> u64 now;
>
> - raw_local_irq_save(flags);
> + local_irq_save(flags);

Hm, wont this cause problems when we trace inside lockdep? Have you tried the
lockdep events - do they still work?

Ingo
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