On Mon, 2016-11-01 at 03:30:31 UTC, Michael Ellerman wrote:

On Fri, 2016-01-08 at 17:50 -0500, Steven Rostedt wrote:

quoted

quoted

Are you going to take this, or do you want me to?

Sorry, yep I'll take it.

I trimmed the change log a bit, final version below.

powerpc: Implement save_stack_trace_regs() to enable kprobe stack tracing

It has come to my attention that kprobe event stack tracing does not
work on powerpc. You can see with the following:

  # cd /sys/kernel/debug/tracing
  # echo stacktrace > trace_options
  # echo 'p kfree' > kprobe_events
  # echo 1 > events/kprobes/enable

Will print the following warning:
  save_stack_trace_regs() not implemented yet.

Although save_stack_trace() (which normal event stack traces use) is
implemented, save_stack_trace_regs() which kprobe events use is not.
This is a cheap attempt to implement that function.

Note, This may have issues if a task tries to get a stack trace from
another task with its regs, because it just passes in "current" to
save_context_stack(). But this does solve the issue with stack tracing
kprobe events.

Reported-by: Chunyu Hu <redacted>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/35de3b1aa16842214e0cd7c603

cheers