tracing: Clean up stack tracing and fix fentry updates
authorSteven Rostedt (Red Hat) <rostedt@goodmis.org>
Thu, 16 Jul 2015 17:24:54 +0000 (13:24 -0400)
committerSteven Rostedt <rostedt@goodmis.org>
Tue, 21 Jul 2015 02:30:50 +0000 (22:30 -0400)
commit72ac426a5bb0cec572d26b4456f8c1e14601694e
tree637bfb15ecc273161b4a5d49e6abc7b136fca6ac
parentd90fd77402d3de56a9ca3df04e5d868d0979dc59
tracing: Clean up stack tracing and fix fentry updates

Akashi Takahiro was porting the stack tracer to arm64 and found some
issues with it. One was that it repeats the top function, due to the
stack frame added by the mcount caller and added by itself. This
was added when fentry came in, and before fentry created its own stack
frame. But x86's fentry now creates its own stack frame, and there's
no need to insert the function again.

This also cleans up the code a bit, where it doesn't need to do something
special for fentry, and doesn't include insertion of a duplicate
entry for the called function being traced.

Link: http://lkml.kernel.org/r/55A646EE.6030402@linaro.org
Some-suggestions-by: Jungseok Lee <jungseoklee85@gmail.com>
Some-suggestions-by: Mark Rutland <mark.rutland@arm.com>
Reported-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
kernel/trace/trace_stack.c