Re: [PATCH 1/3] tracing/function-graph-tracer: introduce __notrace_funcgraph to filter special functions

[Frederic Weisbecker <fweisbec@gmail.com>]

Frederic Weisbecker wrote:
> Impact: trace more functions
> 
> When the function graph tracer is configured, three more files are not traced to prevent
> only four functions to be traced. And this impacts the normal function tracer too.
> 
> arch/x86/kernel/process_64/32.c:
> 
> I had crashes when I let this file traced. After some debugging, I saw that 
> the "current" task point was changed inside__swtich_to(), ie: "write_pda(pcurrent, next_p);" 
> inside process_64.c 
> Since the tracer store the original return address of the function inside current, we had crashes.
> Only __switch_to() has to be traced.
> 
> kernel/module.c and kernel/extable.c:
> 
> Because of a function used internally by the function graph tracer: __kernel_text_address()
> 
> To let the other functions inside these files to be traced, this patch introduces the 
> __notrace_funcgraph function prefix which is __notrace if function graph tracer is 
> configured and nothing if not.
> 


And once again I...did not test under x86-32 :-s