Re: [PATCH] ftrace: distinguish kretprobe'd functions in trace logs

[Abhishek Sagar]

On Fri, Oct 31, 2008 at 11:50 AM, Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
> From: Steven Rostedt <srostedt@xxxxxxxxxx>
> Subject: ftrace: use kretprobe trampoline name to test in output
>
> When a function is kprobed, the return address is set to the
> kprobe_trampoline, or something similar. This caused the output
> of the trace to look confusing when the parent seemed to be this
> "kprobe_trampoline" function.
>
> To fix this, Abhishek Sagar added a test of the instruction pointer
> of the parent to see if it matched the kprobe_trampoline. If it
> did, the output would print a "[unknown/kretprobe'd]" instead.
>
> Unfortunately, not all archs do this the same way, and the trampoline
> function may not be exported, which causes failures in builds.
>
> This patch will compare the name instead of the pointer to see
> if it matches. This prevents us from depending on a function from
> being exported, and should work on all archs. The worst that can
> happen is that an arch might use a different name and then we
> go back to the confusing output. At least the arch will still build.
>
> Signed-off-by: Steven Rostedt <srostedt@xxxxxxxxxx>
> ---
>  kernel/trace/trace.c |   39 +++++++++++++++++++++------------------
>  1 file changed, 21 insertions(+), 18 deletions(-)

Looks good, and worked on x86-32.

Acked-by: Abhishek Sagar <sagar.abhishek@xxxxxxxxx>
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