diff options
| author | Jiri Olsa <jolsa@redhat.com> | 2014-03-02 15:56:38 (GMT) |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2014-03-11 10:57:57 (GMT) |
| commit | cfa77bc4af2c75c0781ee76cde2dd104c6c8e2b7 (patch) | |
| tree | 5ebefacf14f3b4f852179744836f64a1dcd07e7c /kernel/trace | |
| parent | ef11dadb8373fcbe53bdd09ceb262b2f18da10c5 (diff) | |
| download | linux-cfa77bc4af2c75c0781ee76cde2dd104c6c8e2b7.tar.xz | |
perf: Disallow user-space callchains for function trace events
Recent issues with user space callchains processing within
page fault handler tracing showed as Peter said 'there's
just too much fail surface'.
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 <a.p.zijlstra@chello.nl>
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1393775800-13524-2-git-send-email-jolsa@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/trace')
| -rw-r--r-- | kernel/trace/trace_event_perf.c | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c index e854f42..d5e01c3 100644 --- a/kernel/trace/trace_event_perf.c +++ b/kernel/trace/trace_event_perf.c @@ -31,9 +31,18 @@ static int perf_trace_event_perm(struct ftrace_event_call *tp_event, } /* The ftrace function trace is allowed only for root. */ - if (ftrace_event_is_function(tp_event) && - perf_paranoid_tracepoint_raw() && !capable(CAP_SYS_ADMIN)) - return -EPERM; + if (ftrace_event_is_function(tp_event)) { + if (perf_paranoid_tracepoint_raw() && !capable(CAP_SYS_ADMIN)) + return -EPERM; + + /* + * We don't allow user space callchains for function trace + * event, due to issues with page faults while tracing page + * fault handler and its overall trickiness nature. + */ + if (!p_event->attr.exclude_callchain_user) + return -EINVAL; + } /* No tracing, just counting, so no obvious leak */ if (!(p_event->attr.sample_type & PERF_SAMPLE_RAW)) |