[tip:perf/core] perf_events, x86: Fix validate_event bug

[tip-bot for Stephane Eranian]

Commit-ID:  1261a02a0c0ab8e643125705f0d1d83e5090e4d1
Gitweb:     http://git.kernel.org/tip/1261a02a0c0ab8e643125705f0d1d83e5090e4d1
Author:     Stephane Eranian <eranian@xxxxxxxxxx>
AuthorDate: Tue, 24 Nov 2009 05:27:18 -0800
Committer:  Ingo Molnar <mingo@xxxxxxx>
CommitDate: Tue, 24 Nov 2009 19:23:48 +0100

perf_events, x86: Fix validate_event bug

The validate_event() was failing on valid event combinations. The
function was assuming that if x86_schedule_event() returned 0, it
meant error. But x86_schedule_event() returns the counter index and
0 is a perfectly valid value. An error is returned if the function
returns a negative value.

Furthermore, validate_event() was also failing for event groups
because the event->pmu was not set until after
hw_perf_event_init().

Signed-off-by: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: peterz@xxxxxxxxxxxxx
Cc: paulus@xxxxxxxxx
Cc: perfmon2-devel@xxxxxxxxxxxxxxxxxxxxx
Cc: eranian@xxxxxxxxx
LKML-Reference: <4b0bdf36.1818d00a.07cc.25ae@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
--
 arch/x86/kernel/cpu/perf_event.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
 arch/x86/kernel/cpu/perf_event.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index bd87430..c1bbed1 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -2229,10 +2229,10 @@ validate_event(struct cpu_hw_events *cpuc, struct perf_event *event)
 {
 	struct hw_perf_event fake_event = event->hw;
 
-	if (event->pmu != &pmu)
+	if (event->pmu && event->pmu != &pmu)
 		return 0;
 
-	return x86_schedule_event(cpuc, &fake_event);
+	return x86_schedule_event(cpuc, &fake_event) >= 0;
 }
 
 static int validate_group(struct perf_event *event)
--
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