Patch "drm/vc4: Account for interrupts in flight" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

drm/vc4: Account for interrupts in flight

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
drm-vc4-account-for-interrupts-in-flight.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Stefan Schake <[email protected]>
Date: Fri, 10 Nov 2017 02:05:06 +0100
Subject: drm/vc4: Account for interrupts in flight

From: Stefan Schake <[email protected]>

[ Upstream commit 253696ccd613fbdaa5aba1de44c461a058e0a114 ]

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.

---
 drivers/gpu/drm/vc4/vc4_irq.c |    6 ++++++
 1 file changed, 6 insertions(+)

@@ -208,6 +208,9 @@ vc4_irq_postinstall(struct drm_device *d
 {
 	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);
 }
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/drm-vc4-move-irq-enable-to-pm-path.patch queue-4.9/drm-vc4-account-for-interrupts-in-flight.patch