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%3Ba=su...

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 stable@vger.kernel.org know about it.

From foo@baz Thu Feb 1 13:58:04 CET 2018

From: Stefan Schake stschake@gmail.com Date: Fri, 10 Nov 2017 02:05:06 +0100 Subject: drm/vc4: Account for interrupts in flight

From: Stefan Schake stschake@gmail.com

[ 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.

Link: https://github.com/anholt/linux/issues/114 Signed-off-by: Stefan Schake stschake@gmail.com Fixes: d5b1a78a772f ("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-emai... Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpu/drm/vc4/vc4_irq.c | 6 ++++++ 1 file changed, 6 insertions(+)

--- a/drivers/gpu/drm/vc4/vc4_irq.c +++ b/drivers/gpu/drm/vc4/vc4_irq.c @@ -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 stschake@gmail.com are

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