[PATCH] drm: fix uninitialized acquire_ctx fields

[Rob Clark]

The acquire ctx will typically be declared on the stack, which means we
could have garbage values for any uninitialized field.  In this case, it
was triggering WARN_ON()s because 'contended' had garbage value.

Go ahead and use memset() to be more future-proof.

Reported-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
Signed-off-by: Rob Clark <robdclark at gmail.com>
---
 drivers/gpu/drm/drm_modeset_lock.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/drm_modeset_lock.c b/drivers/gpu/drm/drm_modeset_lock.c
index 7c2497d..4e8b244 100644
--- a/drivers/gpu/drm/drm_modeset_lock.c
+++ b/drivers/gpu/drm/drm_modeset_lock.c
@@ -64,6 +64,7 @@
 void drm_modeset_acquire_init(struct drm_modeset_acquire_ctx *ctx,
 		uint32_t flags)
 {
+	memset(ctx, 0, sizeof(ctx));
 	ww_acquire_init(&ctx->ww_ctx, &crtc_ww_class);
 	INIT_LIST_HEAD(&ctx->locked);
 }
-- 
1.9.3