perf_events: Fix bogus copy_to_user() in perf_event_read_group()

When using an event group, the value and id for non leaders events
were wrong due to invalid offset into the outgoing buffer.

Signed-off-by: Stephane Eranian <eranian@google.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: paulus@samba.org
Cc: perfmon2-devel@lists.sourceforge.net
LKML-Reference: <4b0b71e1.0508d00a.075e.ffff84a3@mx.google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 9425c96..accfd7b 100644 (file)
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -1831,7 +1831,7 @@ static int perf_event_read_group(struct perf_event *event,
 
                size = n * sizeof(u64);
 
-               if (copy_to_user(buf + size, values, size)) {
+               if (copy_to_user(buf + ret, values, size)) {
                        ret = -EFAULT;
                        goto unlock;
                }