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>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index a641eb753b8cc92b664966e3a6932c595f07b111..7bc888dfd06ab890c2a55c9b3211f0785146e678 100644 (file)
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -2665,6 +2665,7 @@ 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)