If we call into the shrinker for direct relcaim inside kmalloc, it will
retire the requests. If we retire the vma->last_active while a new
i915_vma_move_to_active() we can upset the delicate bookkeeping required
for the cache. After the possible invocation of the shrinker, we need to
double check the vma->last_active is still valid.
Fixes: 8b293eb53a7d ("drm/i915: Track the last-active inside the i915_vma")
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_vma.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
index ed4e0fb558f7..11d834f94220 100644
--- a/drivers/gpu/drm/i915/i915_vma.c
+++ b/drivers/gpu/drm/i915/i915_vma.c
@@ -942,6 +942,14 @@ static struct i915_gem_active *active_instance(struct i915_vma *vma, u64 idx)
}
active = kmalloc(sizeof(*active), GFP_KERNEL);
+
+ /* kmalloc may retire the vma->last_active request (thanks shrinker)! */
+ if (unlikely(!i915_gem_active_raw(&vma->last_active,
+ &vma->vm->i915->drm.struct_mutex))) {
+ kfree(active);
+ goto out;
+ }
+
if (unlikely(!active))
return ERR_PTR(-ENOMEM);
--
2.18.0
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