drm/i915: Reduce a pin-leak BUG into a WARN

Pin-leaks persist and we get the perennial bug reports of machine
lockups to the BUG_ON(pin_count==MAX). If we instead loudly report that
the object cannot be pinned at that time it should prevent the driver from
locking up, and hopefully restore a semblance of working whilst still
leaving us a OOPS to debug.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 489e2b162b2736b4fc3d43e171ebddb25c66b12e..274d25de521e78c577d5a62456fc812024bbae79 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -3242,7 +3242,8 @@ i915_gem_object_pin(struct drm_i915_gem_object *obj,
 {
        int ret;
 
-       BUG_ON(obj->pin_count == DRM_I915_GEM_OBJECT_MAX_PIN_COUNT);
+       if (WARN_ON(obj->pin_count == DRM_I915_GEM_OBJECT_MAX_PIN_COUNT))
+               return -EBUSY;
 
        if (obj->gtt_space != NULL) {
                if ((alignment && obj->gtt_offset & (alignment - 1)) ||