sd->devnode is released after calling v4l2_subdev_release. Therefore it should be set to NULL so that the subdev won't hold a pointer to a released object. This fixes a reference after free bug in function v4l2_device_unregister_subdev
Cc: stable@vger.kernel.org Fixes: 0e43734d4c46e ("media: v4l2-subdev: add release() internal op") Signed-off-by: Dafna Hirschfeld dafna.hirschfeld@collabora.com Reviewed-by: Ezequiel Garcia ezequiel@collabora.com --- changes since v2: - since this is a regresion fix, I added Fixes and Cc to stable tags, - change the commit title and log to be more clear.
drivers/media/v4l2-core/v4l2-device.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/drivers/media/v4l2-core/v4l2-device.c b/drivers/media/v4l2-core/v4l2-device.c index 63d6b147b21e..2b3595671d62 100644 --- a/drivers/media/v4l2-core/v4l2-device.c +++ b/drivers/media/v4l2-core/v4l2-device.c @@ -177,6 +177,7 @@ static void v4l2_subdev_release(struct v4l2_subdev *sd) { struct module *owner = !sd->owner_v4l2_dev ? sd->owner : NULL;
+ sd->devnode = NULL; if (sd->internal_ops && sd->internal_ops->release) sd->internal_ops->release(sd); module_put(owner);
On 11/20/19 1:22 PM, Dafna Hirschfeld wrote:
sd->devnode is released after calling v4l2_subdev_release. Therefore it should be set to NULL so that the subdev won't hold a pointer to a released object. This fixes a reference after free bug in function v4l2_device_unregister_subdev
Cc: stable@vger.kernel.org Fixes: 0e43734d4c46e ("media: v4l2-subdev: add release() internal op") Signed-off-by: Dafna Hirschfeld dafna.hirschfeld@collabora.com Reviewed-by: Ezequiel Garcia ezequiel@collabora.com
changes since v2:
- since this is a regresion fix, I added Fixes and Cc to stable tags,
- change the commit title and log to be more clear.
drivers/media/v4l2-core/v4l2-device.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/drivers/media/v4l2-core/v4l2-device.c b/drivers/media/v4l2-core/v4l2-device.c index 63d6b147b21e..2b3595671d62 100644 --- a/drivers/media/v4l2-core/v4l2-device.c +++ b/drivers/media/v4l2-core/v4l2-device.c @@ -177,6 +177,7 @@ static void v4l2_subdev_release(struct v4l2_subdev *sd) { struct module *owner = !sd->owner_v4l2_dev ? sd->owner : NULL;
- sd->devnode = NULL; if (sd->internal_ops && sd->internal_ops->release) sd->internal_ops->release(sd);
I'd move the sd->devnode = NULL; line here. That way the sd->internal_ops->release(sd) callback can still use it.
Unless I am missing something?
module_put(owner);
Regards,
Hans
Hi
On 16.01.20 13:57, Hans Verkuil wrote:
On 11/20/19 1:22 PM, Dafna Hirschfeld wrote:
sd->devnode is released after calling v4l2_subdev_release. Therefore it should be set to NULL so that the subdev won't hold a pointer to a released object. This fixes a reference after free bug in function v4l2_device_unregister_subdev
Cc: stable@vger.kernel.org Fixes: 0e43734d4c46e ("media: v4l2-subdev: add release() internal op") Signed-off-by: Dafna Hirschfeld dafna.hirschfeld@collabora.com Reviewed-by: Ezequiel Garcia ezequiel@collabora.com
changes since v2:
since this is a regresion fix, I added Fixes and Cc to stable tags,
change the commit title and log to be more clear.
drivers/media/v4l2-core/v4l2-device.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/drivers/media/v4l2-core/v4l2-device.c b/drivers/media/v4l2-core/v4l2-device.c index 63d6b147b21e..2b3595671d62 100644 --- a/drivers/media/v4l2-core/v4l2-device.c +++ b/drivers/media/v4l2-core/v4l2-device.c @@ -177,6 +177,7 @@ static void v4l2_subdev_release(struct v4l2_subdev *sd) { struct module *owner = !sd->owner_v4l2_dev ? sd->owner : NULL;
- sd->devnode = NULL; if (sd->internal_ops && sd->internal_ops->release) sd->internal_ops->release(sd);
I'd move the sd->devnode = NULL; line here. That way the sd->internal_ops->release(sd) callback can still use it.
Unless I am missing something?
It makes sense although none of the drivers uses this callback since the subdevice should be released in the v4l2_device's release so it seems that this callback can (should?) be removed.
Dafna
module_put(owner);
Regards,
Hans
On 1/17/20 11:35 AM, Dafna Hirschfeld wrote:
Hi
On 16.01.20 13:57, Hans Verkuil wrote:
On 11/20/19 1:22 PM, Dafna Hirschfeld wrote:
sd->devnode is released after calling v4l2_subdev_release. Therefore it should be set to NULL so that the subdev won't hold a pointer to a released object. This fixes a reference after free bug in function v4l2_device_unregister_subdev
Cc: stable@vger.kernel.org Fixes: 0e43734d4c46e ("media: v4l2-subdev: add release() internal op") Signed-off-by: Dafna Hirschfeld dafna.hirschfeld@collabora.com Reviewed-by: Ezequiel Garcia ezequiel@collabora.com
changes since v2:
since this is a regresion fix, I added Fixes and Cc to stable tags,
change the commit title and log to be more clear.
drivers/media/v4l2-core/v4l2-device.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/drivers/media/v4l2-core/v4l2-device.c b/drivers/media/v4l2-core/v4l2-device.c index 63d6b147b21e..2b3595671d62 100644 --- a/drivers/media/v4l2-core/v4l2-device.c +++ b/drivers/media/v4l2-core/v4l2-device.c @@ -177,6 +177,7 @@ static void v4l2_subdev_release(struct v4l2_subdev *sd) { struct module *owner = !sd->owner_v4l2_dev ? sd->owner : NULL;
- sd->devnode = NULL; if (sd->internal_ops && sd->internal_ops->release) sd->internal_ops->release(sd);
I'd move the sd->devnode = NULL; line here. That way the sd->internal_ops->release(sd) callback can still use it.
Unless I am missing something?
It makes sense although none of the drivers uses this callback since the subdevice should be released in the v4l2_device's release so it seems that this callback can (should?) be removed.
If nobody uses it, then I agree that it is better to remove it.
Regards,
Hans
Dafna
module_put(owner);
Regards,
Hans
On 17.01.20 12:46, Hans Verkuil wrote:
On 1/17/20 11:35 AM, Dafna Hirschfeld wrote:
Hi
On 16.01.20 13:57, Hans Verkuil wrote:
On 11/20/19 1:22 PM, Dafna Hirschfeld wrote:
sd->devnode is released after calling v4l2_subdev_release. Therefore it should be set to NULL so that the subdev won't hold a pointer to a released object. This fixes a reference after free bug in function v4l2_device_unregister_subdev
Cc: stable@vger.kernel.org Fixes: 0e43734d4c46e ("media: v4l2-subdev: add release() internal op") Signed-off-by: Dafna Hirschfeld dafna.hirschfeld@collabora.com Reviewed-by: Ezequiel Garcia ezequiel@collabora.com
changes since v2:
since this is a regresion fix, I added Fixes and Cc to stable tags,
change the commit title and log to be more clear.
drivers/media/v4l2-core/v4l2-device.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/drivers/media/v4l2-core/v4l2-device.c b/drivers/media/v4l2-core/v4l2-device.c index 63d6b147b21e..2b3595671d62 100644 --- a/drivers/media/v4l2-core/v4l2-device.c +++ b/drivers/media/v4l2-core/v4l2-device.c @@ -177,6 +177,7 @@ static void v4l2_subdev_release(struct v4l2_subdev *sd) { struct module *owner = !sd->owner_v4l2_dev ? sd->owner : NULL;
- sd->devnode = NULL; if (sd->internal_ops && sd->internal_ops->release) sd->internal_ops->release(sd);
I'd move the sd->devnode = NULL; line here. That way the sd->internal_ops->release(sd) callback can still use it.
Unless I am missing something?
It makes sense although none of the drivers uses this callback since the subdevice should be released in the v4l2_device's release so it seems that this callback can (should?) be removed.
If nobody uses it, then I agree that it is better to remove it.
ok, currently only vimc implements this callback this would change after the patchset `media: vimc: race condition fixes` will be accepted. Then I can send a patch removing it.
Dafna
Regards,
Hans
Dafna
module_put(owner);Regards,
Hans
On Thu, 2020-01-16 at 12:57 +0100, Hans Verkuil wrote:
On 11/20/19 1:22 PM, Dafna Hirschfeld wrote:
sd->devnode is released after calling v4l2_subdev_release. Therefore it should be set to NULL so that the subdev won't hold a pointer to a released object. This fixes a reference after free bug in function v4l2_device_unregister_subdev
Cc: stable@vger.kernel.org Fixes: 0e43734d4c46e ("media: v4l2-subdev: add release() internal op") Signed-off-by: Dafna Hirschfeld dafna.hirschfeld@collabora.com Reviewed-by: Ezequiel Garcia ezequiel@collabora.com
changes since v2:
- since this is a regresion fix, I added Fixes and Cc to stable tags,
- change the commit title and log to be more clear.
drivers/media/v4l2-core/v4l2-device.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/drivers/media/v4l2-core/v4l2-device.c b/drivers/media/v4l2-core/v4l2-device.c index 63d6b147b21e..2b3595671d62 100644 --- a/drivers/media/v4l2-core/v4l2-device.c +++ b/drivers/media/v4l2-core/v4l2-device.c @@ -177,6 +177,7 @@ static void v4l2_subdev_release(struct v4l2_subdev *sd) { struct module *owner = !sd->owner_v4l2_dev ? sd->owner : NULL;
- sd->devnode = NULL; if (sd->internal_ops && sd->internal_ops->release) sd->internal_ops->release(sd);
I'd move the sd->devnode = NULL; line here. That way the sd->internal_ops->release(sd) callback can still use it.
Hi everyone,
Please note this fix is useful to fix a kernel oops when rkisp1 driver is removed.
Can we get a v4 addressing Hans' feedback?
Thanks, Ezequiel
Unless I am missing something?
module_put(owner);
Regards,
Hans
linux-stable-mirror@lists.linaro.org
-
Dafna Hirschfeld -
Ezequiel Garcia -
Hans Verkuil