[patch] drm/vmwgfx: fix a NULL dereference

From: Dan Carpenter
Date: Thu Jan 28 2016 - 04:07:19 EST


We dereference "eaction->event" inside the call to drm_send_event_locked()
so should hold off on setting it to NULL until afterward.

Fixes: fb740cf2492c ("drm: Create drm_send_event helpers")
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c b/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c
index e0edf14..37c305b 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c
@@ -880,8 +880,8 @@ static void vmw_event_fence_action_seq_passed(struct vmw_fence_action *action)
}

list_del_init(&eaction->fpriv_head);
- eaction->event = NULL;
drm_send_event_locked(dev, eaction->event);
+ eaction->event = NULL;
spin_unlock_irqrestore(&dev->event_lock, irq_flags);
}