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From: Stefan Schake <stschake@gmail.com>
To: dri-devel@lists.freedesktop.org
Cc: David Airlie <airlied@linux.ie>,
	linux-rpi-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, Stefan Schake <stschake@gmail.com>
Subject: [PATCH 1/2] drm/vc4: Account for interrupts in flight
Date: Fri, 10 Nov 2017 02:05:06 +0100	[thread overview]
Message-ID: <1510275907-993-2-git-send-email-stschake@gmail.com> (raw)
In-Reply-To: <1510275907-993-1-git-send-email-stschake@gmail.com>

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

diff --git a/drivers/gpu/drm/vc4/vc4_irq.c b/drivers/gpu/drm/vc4/vc4_irq.c
index 7d7af3a..61b2e53 100644
--- a/drivers/gpu/drm/vc4/vc4_irq.c
+++ b/drivers/gpu/drm/vc4/vc4_irq.c
@@ -208,6 +208,9 @@
 {
 	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 @@
 	/* 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);
 }
 
-- 
1.9.1

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WARNING: multiple messages have this Message-ID (diff)
From: Stefan Schake <stschake@gmail.com>
To: dri-devel@lists.freedesktop.org
Cc: linux-rpi-kernel@lists.infradead.org,
	Stefan Schake <stschake@gmail.com>, Eric Anholt <eric@anholt.net>,
	David Airlie <airlied@linux.ie>,
	linux-kernel@vger.kernel.org
Subject: [PATCH 1/2] drm/vc4: Account for interrupts in flight
Date: Fri, 10 Nov 2017 02:05:06 +0100	[thread overview]
Message-ID: <1510275907-993-2-git-send-email-stschake@gmail.com> (raw)
In-Reply-To: <1510275907-993-1-git-send-email-stschake@gmail.com>

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

diff --git a/drivers/gpu/drm/vc4/vc4_irq.c b/drivers/gpu/drm/vc4/vc4_irq.c
index 7d7af3a..61b2e53 100644
--- a/drivers/gpu/drm/vc4/vc4_irq.c
+++ b/drivers/gpu/drm/vc4/vc4_irq.c
@@ -208,6 +208,9 @@
 {
 	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 @@
 	/* 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);
 }
 
-- 
1.9.1

  reply	other threads:[~2017-11-10  1:05 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-11-10  1:05 [PATCH 0/2] drm/vc4: Correctly uninstall interrupts Stefan Schake
2017-11-10  1:05 ` Stefan Schake
2017-11-10  1:05 ` Stefan Schake [this message]
2017-11-10  1:05   ` [PATCH 1/2] drm/vc4: Account for interrupts in flight Stefan Schake
2017-11-14  0:59   ` Eric Anholt
2017-11-14  0:59     ` Eric Anholt
2017-11-10  1:05 ` [PATCH 2/2] drm/vc4: Ensure interrupts are disabled Stefan Schake
2017-11-10  1:05   ` Stefan Schake
2017-11-14  0:18   ` Eric Anholt
2017-11-14  0:18     ` Eric Anholt
2017-11-14 11:43     ` Stefan Schake
2017-11-14 19:44       ` Eric Anholt
2017-11-14 19:44         ` Eric Anholt
2017-11-14 23:18         ` Stefan Schake
2017-11-14 23:18           ` Stefan Schake

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