[PATCH] drm/vc4: Fix NULL pointer dereference in vc4_save_hang_state()

[Boris Brezillon <boris.brezillon@xxxxxxxxxxxxxxxxxx>]

When saving BOs in the hang state we skip one entry of the
kernel_state->bo[] array, thus leaving it to NULL. This leads to a NULL
pointer dereference when, later in this function, we iterate over all
BOs to check their ->madv state.

Fixes: ca26d28bbaa3 ("drm/vc4: improve throughput by pipelining binning and rendering jobs")
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxxxxxxx>
---
 drivers/gpu/drm/vc4/vc4_gem.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/vc4/vc4_gem.c b/drivers/gpu/drm/vc4/vc4_gem.c
index 6c32c89a83a9..19ac7fe0e5db 100644
--- a/drivers/gpu/drm/vc4/vc4_gem.c
+++ b/drivers/gpu/drm/vc4/vc4_gem.c
@@ -208,7 +208,7 @@ vc4_save_hang_state(struct drm_device *dev)
 			kernel_state->bo[j + prev_idx] = &bo->base.base;
 			j++;
 		}
-		prev_idx = j + 1;
+		prev_idx = j;
 	}
 
 	if (exec[0])
-- 
2.11.0