[PATCH 2/3] drm: Avoid NULL dereference for DRM_LEGACY debug message

[Chris Wilson]

smatch warns:

	drivers/gpu/drm/drm_lock.c:188 drm_legacy_lock() warn:
	variable dereferenced before check 'master->lock.hw_lock' (see line 177)

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/drm_lock.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_lock.c b/drivers/gpu/drm/drm_lock.c
index c901f3c5b269..32d43f86a8f2 100644
--- a/drivers/gpu/drm/drm_lock.c
+++ b/drivers/gpu/drm/drm_lock.c
@@ -176,7 +176,8 @@ int drm_legacy_lock(struct drm_device *dev, void *data,
 
 	DRM_DEBUG("%d (pid %d) requests lock (0x%08x), flags = 0x%08x\n",
 		  lock->context, task_pid_nr(current),
-		  master->lock.hw_lock->lock, lock->flags);
+		  master->lock.hw_lock ? master->lock.hw_lock->lock : -1,
+		  lock->flags);
 
 	add_wait_queue(&master->lock.lock_queue, &entry);
 	spin_lock_bh(&master->lock.spinlock);
-- 
2.10.2