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* [PATCH 1/2] drm/meson: Fix invalid pointer in meson_drv_unbind()
@ 2019-03-22 15:26 Jean-Philippe Brucker
  2019-03-22 15:26 ` [PATCH 2/2] drm/meson: Uninstall IRQ handler Jean-Philippe Brucker
                   ` (2 more replies)
  0 siblings, 3 replies; 5+ messages in thread
From: Jean-Philippe Brucker @ 2019-03-22 15:26 UTC (permalink / raw)
  To: narmstrong
  Cc: airlied, khilman, dri-devel, daniel, linux-amlogic, linux-arm-kernel

meson_drv_bind() registers a meson_drm struct as the device's privdata,
but meson_drv_unbind() tries to retrieve a drm_device. This may cause a
segfault on shutdown:

[ 5194.593429] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000197
 ...
[ 5194.788850] Call trace:
[ 5194.791349]  drm_dev_unregister+0x1c/0x118 [drm]
[ 5194.795848]  meson_drv_unbind+0x50/0x78 [meson_drm]

Retrieve the right pointer in meson_drv_unbind().

Fixes: bbbe775ec5b5 ("drm: Add support for Amlogic Meson Graphic Controller")
Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
---
 drivers/gpu/drm/meson/meson_drv.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/meson/meson_drv.c b/drivers/gpu/drm/meson/meson_drv.c
index 2281ed3eb774..7e85802c5398 100644
--- a/drivers/gpu/drm/meson/meson_drv.c
+++ b/drivers/gpu/drm/meson/meson_drv.c
@@ -356,8 +356,8 @@ static int meson_drv_bind(struct device *dev)
 
 static void meson_drv_unbind(struct device *dev)
 {
-	struct drm_device *drm = dev_get_drvdata(dev);
-	struct meson_drm *priv = drm->dev_private;
+	struct meson_drm *priv = dev_get_drvdata(dev);
+	struct drm_device *drm = priv->drm;
 
 	if (priv->canvas) {
 		meson_canvas_free(priv->canvas, priv->canvas_id_osd1);
-- 
2.20.1


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^ permalink raw reply related	[flat|nested] 5+ messages in thread

* [PATCH 2/2] drm/meson: Uninstall IRQ handler
  2019-03-22 15:26 [PATCH 1/2] drm/meson: Fix invalid pointer in meson_drv_unbind() Jean-Philippe Brucker
@ 2019-03-22 15:26 ` Jean-Philippe Brucker
  2019-03-23  9:54   ` Neil Armstrong
  2019-03-23  9:53 ` [PATCH 1/2] drm/meson: Fix invalid pointer in meson_drv_unbind() Neil Armstrong
  2019-03-25 10:19 ` Neil Armstrong
  2 siblings, 1 reply; 5+ messages in thread
From: Jean-Philippe Brucker @ 2019-03-22 15:26 UTC (permalink / raw)
  To: narmstrong
  Cc: airlied, khilman, dri-devel, daniel, linux-amlogic, linux-arm-kernel

meson_drv_unbind() doesn't unregister the IRQ handler, which can lead to
use-after-free if the IRQ fires after unbind:

[   64.656876] Unable to handle kernel paging request at virtual address ffff000011706dbc
...
[   64.662001] pc : meson_irq+0x18/0x30 [meson_drm]

I'm assuming that a similar problem could happen on the error path of
bind(), so uninstall the IRQ handler there as well.

Fixes: bbbe775ec5b5 ("drm: Add support for Amlogic Meson Graphic Controller")
Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
---
 drivers/gpu/drm/meson/meson_drv.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/meson/meson_drv.c b/drivers/gpu/drm/meson/meson_drv.c
index 7e85802c5398..8a4ebcb6405c 100644
--- a/drivers/gpu/drm/meson/meson_drv.c
+++ b/drivers/gpu/drm/meson/meson_drv.c
@@ -337,12 +337,14 @@ static int meson_drv_bind_master(struct device *dev, bool has_components)
 
 	ret = drm_dev_register(drm, 0);
 	if (ret)
-		goto free_drm;
+		goto uninstall_irq;
 
 	drm_fbdev_generic_setup(drm, 32);
 
 	return 0;
 
+uninstall_irq:
+	drm_irq_uninstall(drm);
 free_drm:
 	drm_dev_put(drm);
 
@@ -367,6 +369,7 @@ static void meson_drv_unbind(struct device *dev)
 	}
 
 	drm_dev_unregister(drm);
+	drm_irq_uninstall(drm);
 	drm_kms_helper_poll_fini(drm);
 	drm_mode_config_cleanup(drm);
 	drm_dev_put(drm);
-- 
2.20.1


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^ permalink raw reply related	[flat|nested] 5+ messages in thread

* Re: [PATCH 1/2] drm/meson: Fix invalid pointer in meson_drv_unbind()
  2019-03-22 15:26 [PATCH 1/2] drm/meson: Fix invalid pointer in meson_drv_unbind() Jean-Philippe Brucker
  2019-03-22 15:26 ` [PATCH 2/2] drm/meson: Uninstall IRQ handler Jean-Philippe Brucker
@ 2019-03-23  9:53 ` Neil Armstrong
  2019-03-25 10:19 ` Neil Armstrong
  2 siblings, 0 replies; 5+ messages in thread
From: Neil Armstrong @ 2019-03-23  9:53 UTC (permalink / raw)
  To: Jean-Philippe Brucker
  Cc: airlied, khilman, dri-devel, daniel, linux-amlogic, linux-arm-kernel

Hi Jean-Philippe,

Le 22/03/2019 16:26, Jean-Philippe Brucker a écrit :
> meson_drv_bind() registers a meson_drm struct as the device's privdata,
> but meson_drv_unbind() tries to retrieve a drm_device. This may cause a
> segfault on shutdown:
> 
> [ 5194.593429] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000197
>  ...
> [ 5194.788850] Call trace:
> [ 5194.791349]  drm_dev_unregister+0x1c/0x118 [drm]
> [ 5194.795848]  meson_drv_unbind+0x50/0x78 [meson_drm]
> 
> Retrieve the right pointer in meson_drv_unbind().
> 
> Fixes: bbbe775ec5b5 ("drm: Add support for Amlogic Meson Graphic Controller")
> Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>

Thanks for working on this,
Acked-by: Neil Armstrong <narmstrong@baylibre.com>

I'll push it on drm-misc-fixes

> ---
>  drivers/gpu/drm/meson/meson_drv.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/meson/meson_drv.c b/drivers/gpu/drm/meson/meson_drv.c
> index 2281ed3eb774..7e85802c5398 100644
> --- a/drivers/gpu/drm/meson/meson_drv.c
> +++ b/drivers/gpu/drm/meson/meson_drv.c
> @@ -356,8 +356,8 @@ static int meson_drv_bind(struct device *dev)
>  
>  static void meson_drv_unbind(struct device *dev)
>  {
> -	struct drm_device *drm = dev_get_drvdata(dev);
> -	struct meson_drm *priv = drm->dev_private;
> +	struct meson_drm *priv = dev_get_drvdata(dev);
> +	struct drm_device *drm = priv->drm;
>  
>  	if (priv->canvas) {
>  		meson_canvas_free(priv->canvas, priv->canvas_id_osd1);
> 

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^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH 2/2] drm/meson: Uninstall IRQ handler
  2019-03-22 15:26 ` [PATCH 2/2] drm/meson: Uninstall IRQ handler Jean-Philippe Brucker
@ 2019-03-23  9:54   ` Neil Armstrong
  0 siblings, 0 replies; 5+ messages in thread
From: Neil Armstrong @ 2019-03-23  9:54 UTC (permalink / raw)
  To: Jean-Philippe Brucker
  Cc: airlied, khilman, dri-devel, daniel, linux-amlogic, linux-arm-kernel

Hi Jean-Philippe,

Le 22/03/2019 16:26, Jean-Philippe Brucker a écrit :
> meson_drv_unbind() doesn't unregister the IRQ handler, which can lead to
> use-after-free if the IRQ fires after unbind:
> 
> [   64.656876] Unable to handle kernel paging request at virtual address ffff000011706dbc
> ...
> [   64.662001] pc : meson_irq+0x18/0x30 [meson_drm]
> 
> I'm assuming that a similar problem could happen on the error path of
> bind(), so uninstall the IRQ handler there as well.
> 
> Fixes: bbbe775ec5b5 ("drm: Add support for Amlogic Meson Graphic Controller")
> Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
> ---
>  drivers/gpu/drm/meson/meson_drv.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)

Thanks for working on this,
Acked-by: Neil Armstrong <narmstrong@baylibre.com>

I'll push it on drm-misc-fixes

> 
> diff --git a/drivers/gpu/drm/meson/meson_drv.c b/drivers/gpu/drm/meson/meson_drv.c
> index 7e85802c5398..8a4ebcb6405c 100644
> --- a/drivers/gpu/drm/meson/meson_drv.c
> +++ b/drivers/gpu/drm/meson/meson_drv.c
> @@ -337,12 +337,14 @@ static int meson_drv_bind_master(struct device *dev, bool has_components)
>  
>  	ret = drm_dev_register(drm, 0);
>  	if (ret)
> -		goto free_drm;
> +		goto uninstall_irq;
>  
>  	drm_fbdev_generic_setup(drm, 32);
>  
>  	return 0;
>  
> +uninstall_irq:
> +	drm_irq_uninstall(drm);
>  free_drm:
>  	drm_dev_put(drm);
>  
> @@ -367,6 +369,7 @@ static void meson_drv_unbind(struct device *dev)
>  	}
>  
>  	drm_dev_unregister(drm);
> +	drm_irq_uninstall(drm);
>  	drm_kms_helper_poll_fini(drm);
>  	drm_mode_config_cleanup(drm);
>  	drm_dev_put(drm);
> 

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^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH 1/2] drm/meson: Fix invalid pointer in meson_drv_unbind()
  2019-03-22 15:26 [PATCH 1/2] drm/meson: Fix invalid pointer in meson_drv_unbind() Jean-Philippe Brucker
  2019-03-22 15:26 ` [PATCH 2/2] drm/meson: Uninstall IRQ handler Jean-Philippe Brucker
  2019-03-23  9:53 ` [PATCH 1/2] drm/meson: Fix invalid pointer in meson_drv_unbind() Neil Armstrong
@ 2019-03-25 10:19 ` Neil Armstrong
  2 siblings, 0 replies; 5+ messages in thread
From: Neil Armstrong @ 2019-03-25 10:19 UTC (permalink / raw)
  To: Jean-Philippe Brucker
  Cc: airlied, khilman, dri-devel, daniel, linux-amlogic, linux-arm-kernel

On 22/03/2019 16:26, Jean-Philippe Brucker wrote:
> meson_drv_bind() registers a meson_drm struct as the device's privdata,
> but meson_drv_unbind() tries to retrieve a drm_device. This may cause a
> segfault on shutdown:
> 
> [ 5194.593429] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000197
>  ...
> [ 5194.788850] Call trace:
> [ 5194.791349]  drm_dev_unregister+0x1c/0x118 [drm]
> [ 5194.795848]  meson_drv_unbind+0x50/0x78 [meson_drm]
> 
> Retrieve the right pointer in meson_drv_unbind().
> 
> Fixes: bbbe775ec5b5 ("drm: Add support for Amlogic Meson Graphic Controller")
> Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
> ---
>  drivers/gpu/drm/meson/meson_drv.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/meson/meson_drv.c b/drivers/gpu/drm/meson/meson_drv.c
> index 2281ed3eb774..7e85802c5398 100644
> --- a/drivers/gpu/drm/meson/meson_drv.c
> +++ b/drivers/gpu/drm/meson/meson_drv.c
> @@ -356,8 +356,8 @@ static int meson_drv_bind(struct device *dev)
>  
>  static void meson_drv_unbind(struct device *dev)
>  {
> -	struct drm_device *drm = dev_get_drvdata(dev);
> -	struct meson_drm *priv = drm->dev_private;
> +	struct meson_drm *priv = dev_get_drvdata(dev);
> +	struct drm_device *drm = priv->drm;
>  
>  	if (priv->canvas) {
>  		meson_canvas_free(priv->canvas, priv->canvas_id_osd1);
> 

Applied both to drm-misc-fixes, thanks !

Neil

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^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2019-03-25 10:19 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-03-22 15:26 [PATCH 1/2] drm/meson: Fix invalid pointer in meson_drv_unbind() Jean-Philippe Brucker
2019-03-22 15:26 ` [PATCH 2/2] drm/meson: Uninstall IRQ handler Jean-Philippe Brucker
2019-03-23  9:54   ` Neil Armstrong
2019-03-23  9:53 ` [PATCH 1/2] drm/meson: Fix invalid pointer in meson_drv_unbind() Neil Armstrong
2019-03-25 10:19 ` Neil Armstrong

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