Disabling user space stack dump for function trace event. Recent issues with user space callchains processing within page fault handler tracing showed as Peter said 'there's just too much fail surface'.
The user space stack dump is just another source of the this issue. Related list discussions: http://marc.info/?t=139302086500001&r=1&w=2 http://marc.info/?t=139301437300003&r=1&w=2 Suggested-by: Peter Zijlstra <[email protected]> Signed-off-by: Jiri Olsa <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Paul Mackerras <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Arnaldo Carvalho de Melo <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: Vince Weaver <[email protected]> Cc: Steven Rostedt <[email protected]> --- kernel/trace/trace_event_perf.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c index d5e01c3..c894614 100644 --- a/kernel/trace/trace_event_perf.c +++ b/kernel/trace/trace_event_perf.c @@ -42,6 +42,13 @@ static int perf_trace_event_perm(struct ftrace_event_call *tp_event, */ if (!p_event->attr.exclude_callchain_user) return -EINVAL; + + /* + * Same reason to disable user stack dump as for user space + * callchains above. + */ + if (p_event->attr.sample_type & PERF_SAMPLE_STACK_USER) + return -EINVAL; } /* No tracing, just counting, so no obvious leak */ -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
