overlay: Write out the assumption for kernel-provided data

The code assumes (correctly) that perf_event_header's size is
non-zero. Write that out so static analysis also knows it.

Signed-off-by: Petri Latvala <petri.latvala@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Arkadiusz Hiler <arkadiusz.hiler@intel.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/overlay/gpu-perf.c b/overlay/gpu-perf.c
index 5629f826..7addd78d 100644
--- a/overlay/gpu-perf.c
+++ b/overlay/gpu-perf.c
@@ -494,6 +494,7 @@ int gpu_perf_update(struct gpu_perf *gp)
 			const struct perf_event_header *header;
 
 			header = (const struct perf_event_header *)(data + (tail & mask));
+			assert(header->size > 0);
 			if (header->size > head - tail)
 				break;