Commit 253696cc authored Nov 10, 2017 by Stefan Schake Committed by Eric Anholt Nov 13, 2017

drm/vc4: Account for interrupts in flight

Synchronously disable the IRQ to make the following cancel_work_sync
invocation effective.

An interrupt in flight could enqueue further overflow mem work. As we
free the binner BO immediately following vc4_irq_uninstall this caused
a NULL pointer dereference in the work callback vc4_overflow_mem_work.

Link: https://github.com/anholt/linux/issues/114


Signed-off-by: Stefan Schake <stschake@gmail.com>
Fixes: d5b1a78a ("drm/vc4: Add support for drawing 3D frames.")
Signed-off-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Eric Anholt <eric@anholt.net>
Link: https://patchwork.freedesktop.org/patch/msgid/1510275907-993-2-git-send-email-stschake@gmail.com

parent 44419ce7

drivers/gpu/drm/vc4/vc4_irq.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -208,6 +208,9 @@ vc4_irq_postinstall(struct drm_device *dev)
		{
		struct vc4_dev *vc4 = to_vc4_dev(dev);

		/* Undo the effects of a previous vc4_irq_uninstall. */
		enable_irq(dev->irq);

		/* Enable both the render done and out of memory interrupts. */
		V3D_WRITE(V3D_INTENA, V3D_DRIVER_IRQS);

		@@ -225,6 +228,9 @@ vc4_irq_uninstall(struct drm_device *dev)
		/* Clear any pending interrupts we might have left. */
		V3D_WRITE(V3D_INTCTL, V3D_DRIVER_IRQS);

		/* Finish any interrupt handler still in flight. */
		disable_irq(dev->irq);

		cancel_work_sync(&vc4->overflow_mem_work);
		}