perf: Fix stack data leak

the "reserved" field was not initialized to zero, resulting in 4 bytes
of stack data leaking to userspace....

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>

diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index 5c6fae4f43d88c08b1532d4b72d009e2327ae7b5..ff854fd89a8145f34201cd7fb8c302bfa50bfdc5 100644 (file)
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -2666,6 +2666,7 @@ static void perf_counter_output(struct perf_counter *counter, int nmi,
                header.size += sizeof(cpu_entry);
 
                cpu_entry.cpu = raw_smp_processor_id();
+               cpu_entry.reserved = 0;
        }
 
        if (sample_type & PERF_SAMPLE_PERIOD)