[Intel-gfx] [PATCH] drm: Fix locking gotcha in page_flip ioctl

[Daniel Vetter]

We want to lock the primary plane, not the cursor (which might be
optional). Real bad case of copy-paste fail, unfortunately our CI
didn't catch that because i915 does have a cursor plane.

Cc: Eric Anholt <eric at anholt.net>
Reported-by: Eric Anholt <eric at anholt.net>
Fixes: 29dc0d1de182 ("drm: Roll out acquire context for the page_flip ioctl")
Cc: Harry Wentland <harry.wentland at amd.com>
Cc: Daniel Vetter <daniel.vetter at intel.com>
Cc: Jani Nikula <jani.nikula at linux.intel.com>
Cc: Sean Paul <seanpaul at chromium.org>
Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
---
 drivers/gpu/drm/drm_plane.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_plane.c b/drivers/gpu/drm/drm_plane.c
index 3a6de27bafed..838ca742a28b 100644
--- a/drivers/gpu/drm/drm_plane.c
+++ b/drivers/gpu/drm/drm_plane.c
@@ -871,7 +871,7 @@ int drm_mode_page_flip_ioctl(struct drm_device *dev,
 	ret = drm_modeset_lock(&crtc->mutex, &ctx);
 	if (ret)
 		goto out;
-	ret = drm_modeset_lock(&crtc->cursor->mutex, &ctx);
+	ret = drm_modeset_lock(&crtc->primary->mutex, &ctx);
 	if (ret)
 		goto out;
 
-- 
2.11.0