On Fri, 25 Aug 2017 21:49:37 +0800 Zhou Chengming <[email protected]> wrote:
> When run perf on the ftrace:function tracepoint, there is a bug > which can be reproduced by: > > perf record -e ftrace:function -a sleep 20 & > perf record -e ftrace:function ls > perf script > > ls 10304 [005] 171.853235: ftrace:function: > perf_output_begin > ls 10304 [005] 171.853237: ftrace:function: > perf_output_begin > ls 10304 [005] 171.853239: ftrace:function: > task_tgid_nr_ns > ls 10304 [005] 171.853240: ftrace:function: > task_tgid_nr_ns > ls 10304 [005] 171.853242: ftrace:function: > __task_pid_nr_ns > ls 10304 [005] 171.853244: ftrace:function: > __task_pid_nr_ns > > We can see that all the function traces are doubled in perf.data > of "ls". > > The problem is caused by the inconsistency of the register > function perf_ftrace_event_register() with the probe function > perf_ftrace_function_call(). The former registers one probe > for every perf_event. And the latter handles all perf_events > on the current cpu. So when two perf_events on the current cpu, > the traces of them will be doubled. > > So this patch adds an extra parameter "event" for perf_tp_event, > only send sample data to this event when it's not NULL. > > Signed-off-by: Zhou Chengming <[email protected]> > --- > include/linux/perf_event.h | 2 +- > include/linux/trace_events.h | 4 ++-- > kernel/events/core.c | 13 +++++++++---- > kernel/trace/trace_event_perf.c | 4 +++- > kernel/trace/trace_kprobe.c | 4 ++-- > kernel/trace/trace_syscalls.c | 4 ++-- > kernel/trace/trace_uprobe.c | 2 +- The trace files look fine to me. Acked-by: Steven Rostedt (VMware) <[email protected]> -- Steve > 7 files changed, 20 insertions(+), 13 deletions(-) >
