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authorJiri Olsa <jolsa@redhat.com>2014-03-02 16:56:38 +0100
committerIngo Molnar <mingo@kernel.org>2014-03-11 11:57:57 +0100
commitcfa77bc4af2c75c0781ee76cde2dd104c6c8e2b7 (patch)
tree5ebefacf14f3b4f852179744836f64a1dcd07e7c /kernel/trace
parentef11dadb8373fcbe53bdd09ceb262b2f18da10c5 (diff)
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.c15
1 files changed, 12 insertions, 3 deletions
diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index e854f420e03..d5e01c3f4e6 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))