From af6261031317f646d22f994c0b467521e47aa49f Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Mon, 20 Sep 2010 10:31:40 +0100 Subject: [PATCH] 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 --- drivers/gpu/drm/i915/i915_gem_evict.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_gem_evict.c b/drivers/gpu/drm/i915/i915_gem_evict.c index 72cae3cccad..e85246ef691 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 -- 2.20.1