Re: [PATCH 0/1] x86: Eliminate bp argument from the stack tracing routines

[Frederic Weisbecker <fweisbec@gmail.com>]

On Fri, Nov 05, 2010 at 07:14:33AM -0400, Søren Sandmann Pedersen wrote:
> Hi,
> 
> This is a resurrection of an old patch that I sent about a year ago:
> 
>      http://lkml.org/lkml/2009/10/22/192
> 
> At the time, I thought the patch broke perf callchains on 64 bit, but
> it turns out that those are broken even without this patch. 
> 
> I don't know why that is, but I now think the patch is correct and to
> blame.
> 
> (FWIW, this
> 
> diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
> index 461a85d..d977d26 100644
> --- a/arch/x86/kernel/cpu/perf_event.c
> +++ b/arch/x86/kernel/cpu/perf_event.c
> @@ -1653,7 +1653,7 @@ static const struct stacktrace_ops backtrace_ops = {
>  	.warning_symbol		= backtrace_warning_symbol,
>  	.stack			= backtrace_stack,
>  	.address		= backtrace_address,
> -	.walk_stack		= print_context_stack_bp,
> +	.walk_stack		= print_context_stack,
>  };
> 
> makes it produce correct kernel callchains. And yes, I did compile the
> kernel with CONFIG_FRAME_POINTER).



What do you see is broken in 64 bits perf callchains? Can you please provide
me more details so that I can fix the issue?

Thanks.