From: Chris Wilson Date: Fri, 23 Jul 2010 22:18:50 +0000 (+0100) Subject: drm/i915: Repeat unbinding during free if interrupted (v6) X-Git-Tag: MMI-PSA29.97-13-9~22422^2~70^2~5 X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=be72615bcf4d5b7b314d836c5e1b4baa4b65dad1;p=GitHub%2FMotorolaMobilityLLC%2Fkernel-slsi.git drm/i915: Repeat unbinding during free if interrupted (v6) If during the freeing of an object the unbind is interrupted by a system call, which is quite possible if we have outstanding GPU writes that must be flushed, the unbind is silently aborted. This still leaves the AGP region and backing pages allocated, and perhaps more importantly, the object remains upon the various lists exposing us to memory corruption. I think this is the cause behind the use-after-free, such as Bug 15664 - Graphics hang and kernel backtrace when starting Azureus with Compiz enabled https://bugzilla.kernel.org/show_bug.cgi?id=15664 v2: Daniel Vetter reminded me that kernel space programming is never easy. We cannot simply spin to clear the pending signal and so must deferred the freeing of the object until later. v3: Run from the top level retire requests. v4: Tested with P(return -ERESTARTSYS)=.5 from i915_gem_do_wait_request() v5: Rebase against Eric's for-linus tree. v6: Refactor, split and add a comment about avoiding unbounded recursion. Signed-off-by: Chris Wilson Cc: Daniel Vetter Signed-off-by: Eric Anholt --- diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index a27780b7aef2..906663b9929e 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -551,6 +551,14 @@ typedef struct drm_i915_private { /** LRU list of objects with fence regs on them. */ struct list_head fence_list; + /** + * List of objects currently pending being freed. + * + * These objects are no longer in use, but due to a signal + * we were prevented from freeing them at the appointed time. + */ + struct list_head deferred_free_list; + /** * We leave the user IRQ off as much as possible, * but this means that requests will finish and never diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index 138ca6ea5ef7..f45f385c84cd 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -53,6 +53,7 @@ static int i915_gem_evict_from_inactive_list(struct drm_device *dev); static int i915_gem_phys_pwrite(struct drm_device *dev, struct drm_gem_object *obj, struct drm_i915_gem_pwrite *args, struct drm_file *file_priv); +static void i915_gem_free_object_tail(struct drm_gem_object *obj); static LIST_HEAD(shrink_list); static DEFINE_SPINLOCK(shrink_list_lock); @@ -1755,6 +1756,20 @@ i915_gem_retire_requests(struct drm_device *dev) { drm_i915_private_t *dev_priv = dev->dev_private; + if (!list_empty(&dev_priv->mm.deferred_free_list)) { + struct drm_i915_gem_object *obj_priv, *tmp; + + /* We must be careful that during unbind() we do not + * accidentally infinitely recurse into retire requests. + * Currently: + * retire -> free -> unbind -> wait -> retire_ring + */ + list_for_each_entry_safe(obj_priv, tmp, + &dev_priv->mm.deferred_free_list, + list) + i915_gem_free_object_tail(&obj_priv->base); + } + i915_gem_retire_requests_ring(dev, &dev_priv->render_ring); if (HAS_BSD(dev)) i915_gem_retire_requests_ring(dev, &dev_priv->bsd_ring); @@ -4458,20 +4473,19 @@ int i915_gem_init_object(struct drm_gem_object *obj) return 0; } -void i915_gem_free_object(struct drm_gem_object *obj) +static void i915_gem_free_object_tail(struct drm_gem_object *obj) { struct drm_device *dev = obj->dev; + drm_i915_private_t *dev_priv = dev->dev_private; struct drm_i915_gem_object *obj_priv = to_intel_bo(obj); + int ret; - trace_i915_gem_object_destroy(obj); - - while (obj_priv->pin_count > 0) - i915_gem_object_unpin(obj); - - if (obj_priv->phys_obj) - i915_gem_detach_phys_object(dev, obj); - - i915_gem_object_unbind(obj); + ret = i915_gem_object_unbind(obj); + if (ret == -ERESTARTSYS) { + list_move(&obj_priv->list, + &dev_priv->mm.deferred_free_list); + return; + } if (obj_priv->mmap_offset) i915_gem_free_mmap_offset(obj); @@ -4483,6 +4497,22 @@ void i915_gem_free_object(struct drm_gem_object *obj) kfree(obj_priv); } +void i915_gem_free_object(struct drm_gem_object *obj) +{ + struct drm_device *dev = obj->dev; + struct drm_i915_gem_object *obj_priv = to_intel_bo(obj); + + trace_i915_gem_object_destroy(obj); + + while (obj_priv->pin_count > 0) + i915_gem_object_unpin(obj); + + if (obj_priv->phys_obj) + i915_gem_detach_phys_object(dev, obj); + + i915_gem_free_object_tail(obj); +} + /** Unbinds all inactive objects. */ static int i915_gem_evict_from_inactive_list(struct drm_device *dev) @@ -4756,6 +4786,7 @@ i915_gem_load(struct drm_device *dev) INIT_LIST_HEAD(&dev_priv->mm.gpu_write_list); INIT_LIST_HEAD(&dev_priv->mm.inactive_list); INIT_LIST_HEAD(&dev_priv->mm.fence_list); + INIT_LIST_HEAD(&dev_priv->mm.deferred_free_list); INIT_LIST_HEAD(&dev_priv->render_ring.active_list); INIT_LIST_HEAD(&dev_priv->render_ring.request_list); if (HAS_BSD(dev)) {