From: Maarten Lankhorst <m.b.lankhorst@gmail.com>
Date: Thu, 27 Jun 2013 11:38:22 +0000 (+0200)
Subject: drm/nouveau: complain loudly if buffer is pinned during destruction
X-Git-Url: https://rtime.felk.cvut.cz/gitweb/linux-imx.git/commitdiff_plain/27f06b2dbb84cf44b9ff404db1b93f14796ba559

drm/nouveau: complain loudly if buffer is pinned during destruction

Shouldn't happen, and we invert the struct_mutex with reservation here,
potentially leading to deadlocks. Once reservations become lockdep annotated,
lockdep will go splat on this.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Acked-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
---

diff --git a/drivers/gpu/drm/nouveau/nouveau_gem.c b/drivers/gpu/drm/nouveau/nouveau_gem.c
index b4b4d0c1f4af..705470600e48 100644
--- a/drivers/gpu/drm/nouveau/nouveau_gem.c
+++ b/drivers/gpu/drm/nouveau/nouveau_gem.c
@@ -50,7 +50,8 @@ nouveau_gem_object_del(struct drm_gem_object *gem)
 		return;
 	nvbo->gem = NULL;
 
-	if (unlikely(nvbo->pin_refcnt)) {
+	/* Lockdep hates you for doing reserve with gem object lock held */
+	if (WARN_ON_ONCE(nvbo->pin_refcnt)) {
 		nvbo->pin_refcnt = 1;
 		nouveau_bo_unpin(nvbo);
 	}