From: Karol Herbst Date: Wed, 20 Apr 2022 09:57:20 +0000 (+0200) Subject: drm/i915: Fix race in __i915_vma_remove_closed X-Git-Tag: baikal/mips/sdk6.1~5843^2~1^2 X-Git-Url: https://git.baikalelectronics.ru/sdk/?a=commitdiff_plain;h=09ca33a0fe97e550f78ec61a1a95ad4e165478db;p=kernel.git drm/i915: Fix race in __i915_vma_remove_closed i915_vma_reopen checked if the vma is closed before without taking the lock. So multiple threads could attempt removing the vma. Instead the lock needs to be taken before actually checking. v2: move struct declaration Cc: Chris Wilson Cc: intel-gfx@lists.freedesktop.org Cc: dri-devel@lists.freedesktop.org Cc: # v5.3+ Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/5732 Signed-off-by: Karol Herbst Fixes: 597d87fcbca0 ("drm/i915: Move object close under its own lock") Reviewed-by: Tvrtko Ursulin Signed-off-by: Tvrtko Ursulin Link: https://patchwork.freedesktop.org/patch/msgid/20220420095720.3331609-1-kherbst@redhat.com (cherry picked from commit 1df1c79cbb7ac9bf148930be3418973c76ba8dde) Signed-off-by: Joonas Lahtinen --- diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c index 94fcdb7bd21d3..eeaa8d0d04075 100644 --- a/drivers/gpu/drm/i915/i915_vma.c +++ b/drivers/gpu/drm/i915/i915_vma.c @@ -1605,17 +1605,17 @@ void i915_vma_close(struct i915_vma *vma) static void __i915_vma_remove_closed(struct i915_vma *vma) { - struct intel_gt *gt = vma->vm->gt; - - spin_lock_irq(>->closed_lock); list_del_init(&vma->closed_link); - spin_unlock_irq(>->closed_lock); } void i915_vma_reopen(struct i915_vma *vma) { + struct intel_gt *gt = vma->vm->gt; + + spin_lock_irq(>->closed_lock); if (i915_vma_is_closed(vma)) __i915_vma_remove_closed(vma); + spin_unlock_irq(>->closed_lock); } void i915_vma_release(struct kref *ref) @@ -1641,6 +1641,7 @@ static void force_unbind(struct i915_vma *vma) static void release_references(struct i915_vma *vma) { struct drm_i915_gem_object *obj = vma->obj; + struct intel_gt *gt = vma->vm->gt; GEM_BUG_ON(i915_vma_is_active(vma)); @@ -1650,7 +1651,9 @@ static void release_references(struct i915_vma *vma) rb_erase(&vma->obj_node, &obj->vma.tree); spin_unlock(&obj->vma.lock); + spin_lock_irq(>->closed_lock); __i915_vma_remove_closed(vma); + spin_unlock_irq(>->closed_lock); __i915_vma_put(vma); }