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 <chuhu@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
1 file changed