Due to i915_perf assuming that it can use the i915_gem_context reference
to protect its i915->gem.contexts.list iteration, we need to defer removal
of the context from the list until last reference to the context is put.
However, there is a risk of triggering kernel warning on contexts list not
empty at driver release time if we deleagate that task to a worker for
i915_gem_context_release_work(), unless that work is flushed first.
Unfortunately, it is not flushed on driver release. Fix it.
Instead of additionally calling flush_workqueue(), either directly or via
a new dedicated wrapper around it, replace last call to
i915_gem_drain_freed_objects() with existing i915_gem_drain_workqueue()
that performs both tasks.
Fixes: 75eefd82581f ("drm/i915: Release i915_gem_context from a worker")
Suggested-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Janusz Krzysztofik <janusz.krzysztofik@xxxxxxxxxxxxxxx>
Reviewed-by: Andi Shyti <andi.shyti@xxxxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxx # v5.16+
---
drivers/gpu/drm/i915/i915_gem.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index c8e14ed9c2a96..172c29a15f118 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1195,7 +1195,8 @@ void i915_gem_driver_release(struct drm_i915_private *dev_priv)
intel_uc_cleanup_firmwares(&to_gt(dev_priv)->uc);
- i915_gem_drain_freed_objects(dev_priv);
+ /* Flush any outstanding work, including i915_gem_context.release_work. */
+ i915_gem_drain_workqueue(dev_priv);
drm_WARN_ON(&dev_priv->drm, !list_empty(&dev_priv->gem.contexts.list));
}
--
2.25.1
