From: Chris Wilson Date: Mon, 20 Sep 2010 09:31:40 +0000 (+0100) Subject: drm/i915: Hold a reference to the object whilst unbinding the eviction list X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=af6261031317f646d22f994c0b467521e47aa49f;p=deliverable%2Flinux.git drm/i915: Hold a reference to the object whilst unbinding the eviction list During heavy aperture thrashing we may be forced to wait upon several active objects during eviction. The active list may be the last reference to these objects and so the action of waiting upon one of them may cause another to be freed (and itself unbound). To prevent the object disappearing underneath us, we need to acquire and hold a reference whilst unbinding. This should fix the reported page refcount OOPS: kernel BUG at drivers/gpu/drm/i915/i915_gem.c:1444! ... RIP: 0010:[] [] i915_gem_object_put_pages+0x25/0xf5 [i915] Call Trace: [] i915_gem_object_unbind+0xc5/0x1a7 [i915] [] i915_gem_evict_something+0x3bd/0x409 [i915] [] ? drm_gem_object_lookup+0x27/0x57 [drm] [] i915_gem_object_bind_to_gtt+0x1d3/0x279 [i915] [] i915_gem_object_pin+0xa3/0x146 [i915] [] ? drm_gem_object_lookup+0x4c/0x57 [drm] [] i915_gem_do_execbuffer+0x50d/0xe32 [i915] Reported-by: Shawn Starr Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=18902 Signed-off-by: Chris Wilson --- diff --git a/drivers/gpu/drm/i915/i915_gem_evict.c b/drivers/gpu/drm/i915/i915_gem_evict.c index 72cae3cccad8..e85246ef691c 100644 --- a/drivers/gpu/drm/i915/i915_gem_evict.c +++ b/drivers/gpu/drm/i915/i915_gem_evict.c @@ -79,6 +79,7 @@ mark_free(struct drm_i915_gem_object *obj_priv, struct list_head *unwind) { list_add(&obj_priv->evict_list, unwind); + drm_gem_object_reference(&obj_priv->base); return drm_mm_scan_add_block(obj_priv->gtt_space); } @@ -165,6 +166,7 @@ i915_gem_evict_something(struct drm_device *dev, int min_size, unsigned alignmen list_for_each_entry(obj_priv, &unwind_list, evict_list) { ret = drm_mm_scan_remove_block(obj_priv->gtt_space); BUG_ON(ret); + drm_gem_object_unreference(&obj_priv->base); } /* We expect the caller to unpin, evict all and try again, or give up. @@ -181,18 +183,21 @@ found: * scanning, therefore store to be evicted objects on a * temporary list. */ list_move(&obj_priv->evict_list, &eviction_list); - } + } else + drm_gem_object_unreference(&obj_priv->base); } /* Unbinding will emit any required flushes */ list_for_each_entry_safe(obj_priv, tmp_obj_priv, &eviction_list, evict_list) { #if WATCH_LRU - DRM_INFO("%s: evicting %p\n", __func__, obj); + DRM_INFO("%s: evicting %p\n", __func__, &obj_priv->base); #endif ret = i915_gem_object_unbind(&obj_priv->base); if (ret) return ret; + + drm_gem_object_unreference(&obj_priv->base); } /* The just created free hole should be on the top of the free stack