Currently the set_alt callback immediately disables the endpoint and queues
the v4l2 streamoff event. However, as the streamoff event is processed
asynchronously, it is possible that the video_pump thread attempts to queue
requests to an already disabled endpoint.
This change moves disabling usb endpoint to the end of streamoff event
callback. As the endpoint's state can no longer be used, video_pump is
now guarded by uvc->state as well. To be consistent with the actual
streaming state, uvc->state is now toggled between CONNECTED and STREAMING
from the v4l2 event callback only.
Link: https://lore.kernel.org/20230615171558.GK741@pendragon.ideasonboard.com/
Link: https://lore.kernel.org/20230531085544.253363-1-dan.scally@ideasonboard.com/
Reviewed-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Tested-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Signed-off-by: Avichal Rakesh <arakesh@google.com>
---
v1 -> v2: Rebased to ToT and reworded commit message.
v2 -> v3: Fix email threading goof-up
v3 -> v4: Address review comments & re-rebase to ToT
v4 -> v5: Add Reviewed-by & Tested-by
v5 -> v6: No change
v6 -> v7: No change
v7 -> v8: No change. Getting back in review queue
drivers/usb/gadget/function/f_uvc.c | 11 +++++------
drivers/usb/gadget/function/f_uvc.h | 2 +-
drivers/usb/gadget/function/uvc.h | 2 +-
drivers/usb/gadget/function/uvc_v4l2.c | 20 +++++++++++++++++---
drivers/usb/gadget/function/uvc_video.c | 3 ++-
5 files changed, 26 insertions(+), 12 deletions(-)
diff --git a/drivers/usb/gadget/function/f_uvc.c b/drivers/usb/gadget/function/f_uvc.c
index faa398109431..ae08341961eb 100644
--- a/drivers/usb/gadget/function/f_uvc.c
+++ b/drivers/usb/gadget/function/f_uvc.c
@@ -263,10 +263,13 @@ uvc_function_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
return 0;
}
-void uvc_function_setup_continue(struct uvc_device *uvc)
+void uvc_function_setup_continue(struct uvc_device *uvc, int disable_ep)
{
struct usb_composite_dev *cdev = uvc->func.config->cdev;
+ if (disable_ep && uvc->video.ep)
+ usb_ep_disable(uvc->video.ep);
+
usb_composite_setup_continue(cdev);
}
@@ -337,15 +340,11 @@ uvc_function_set_alt(struct usb_function *f, unsigned interface, unsigned alt)
if (uvc->state != UVC_STATE_STREAMING)
return 0;
- if (uvc->video.ep)
- usb_ep_disable(uvc->video.ep);
-
memset(&v4l2_event, 0, sizeof(v4l2_event));
v4l2_event.type = UVC_EVENT_STREAMOFF;
v4l2_event_queue(&uvc->vdev, &v4l2_event);
- uvc->state = UVC_STATE_CONNECTED;
- return 0;
+ return USB_GADGET_DELAYED_STATUS;
case 1:
if (uvc->state != UVC_STATE_CONNECTED)
diff --git a/drivers/usb/gadget/function/f_uvc.h b/drivers/usb/gadget/function/f_uvc.h
index 1db972d4beeb..e7f9f13f14dc 100644
--- a/drivers/usb/gadget/function/f_uvc.h
+++ b/drivers/usb/gadget/function/f_uvc.h
@@ -11,7 +11,7 @@
struct uvc_device;
-void uvc_function_setup_continue(struct uvc_device *uvc);
+void uvc_function_setup_continue(struct uvc_device *uvc, int disale_ep);
void uvc_function_connect(struct uvc_device *uvc);
diff --git a/drivers/usb/gadget/function/uvc.h b/drivers/usb/gadget/function/uvc.h
index 6751de8b63ad..989bc6b4e93d 100644
--- a/drivers/usb/gadget/function/uvc.h
+++ b/drivers/usb/gadget/function/uvc.h
@@ -177,7 +177,7 @@ struct uvc_file_handle {
* Functions
*/
-extern void uvc_function_setup_continue(struct uvc_device *uvc);
+extern void uvc_function_setup_continue(struct uvc_device *uvc, int disable_ep);
extern void uvc_function_connect(struct uvc_device *uvc);
extern void uvc_function_disconnect(struct uvc_device *uvc);
diff --git a/drivers/usb/gadget/function/uvc_v4l2.c b/drivers/usb/gadget/function/uvc_v4l2.c
index 3f0a9795c0d4..7cb8d027ff0c 100644
--- a/drivers/usb/gadget/function/uvc_v4l2.c
+++ b/drivers/usb/gadget/function/uvc_v4l2.c
@@ -451,7 +451,7 @@ uvc_v4l2_streamon(struct file *file, void *fh, enum v4l2_buf_type type)
* Complete the alternate setting selection setup phase now that
* userspace is ready to provide video frames.
*/
- uvc_function_setup_continue(uvc);
+ uvc_function_setup_continue(uvc, 0);
uvc->state = UVC_STATE_STREAMING;
return 0;
@@ -463,11 +463,18 @@ uvc_v4l2_streamoff(struct file *file, void *fh, enum v4l2_buf_type type)
struct video_device *vdev = video_devdata(file);
struct uvc_device *uvc = video_get_drvdata(vdev);
struct uvc_video *video = &uvc->video;
+ int ret = 0;
if (type != video->queue.queue.type)
return -EINVAL;
- return uvcg_video_enable(video, 0);
+ uvc->state = UVC_STATE_CONNECTED;
+ ret = uvcg_video_enable(video, 0);
+ if (ret < 0)
+ return ret;
+
+ uvc_function_setup_continue(uvc, 1);
+ return 0;
}
static int
@@ -500,6 +507,14 @@ uvc_v4l2_subscribe_event(struct v4l2_fh *fh,
static void uvc_v4l2_disable(struct uvc_device *uvc)
{
uvc_function_disconnect(uvc);
+ /*
+ * Drop uvc->state to CONNECTED if it was streaming before.
+ * This ensures that the usb_requests are no longer queued
+ * to the controller.
+ */
+ if (uvc->state == UVC_STATE_STREAMING)
+ uvc->state = UVC_STATE_CONNECTED;
+
uvcg_video_enable(&uvc->video, 0);
uvcg_free_buffers(&uvc->video.queue);
uvc->func_connected = false;
@@ -647,4 +662,3 @@ const struct v4l2_file_operations uvc_v4l2_fops = {
.get_unmapped_area = uvcg_v4l2_get_unmapped_area,
#endif
};
-
diff --git a/drivers/usb/gadget/function/uvc_video.c b/drivers/usb/gadget/function/uvc_video.c
index 91af3b1ef0d4..c334802ac0a4 100644
--- a/drivers/usb/gadget/function/uvc_video.c
+++ b/drivers/usb/gadget/function/uvc_video.c
@@ -384,13 +384,14 @@ static void uvcg_video_pump(struct work_struct *work)
struct uvc_video_queue *queue = &video->queue;
/* video->max_payload_size is only set when using bulk transfer */
bool is_bulk = video->max_payload_size;
+ struct uvc_device *uvc = video->uvc;
struct usb_request *req = NULL;
struct uvc_buffer *buf;
unsigned long flags;
bool buf_done;
int ret;
- while (video->ep->enabled) {
+ while (uvc->state == UVC_STATE_STREAMING && video->ep->enabled) {
/*
* Retrieve the first available USB request, protected by the
* request lock.
--
2.42.0.758.gaed0368e0e-goog
On 10/24/23 11:36, Avichal Rakesh wrote:
> Currently the set_alt callback immediately disables the endpoint and queues
> the v4l2 streamoff event. However, as the streamoff event is processed
> asynchronously, it is possible that the video_pump thread attempts to queue
> requests to an already disabled endpoint.
>
> This change moves disabling usb endpoint to the end of streamoff event
> callback. As the endpoint's state can no longer be used, video_pump is
> now guarded by uvc->state as well. To be consistent with the actual
> streaming state, uvc->state is now toggled between CONNECTED and STREAMING
> from the v4l2 event callback only.
>
> Link: https://lore.kernel.org/20230615171558.GK741@pendragon.ideasonboard.com/
> Link: https://lore.kernel.org/20230531085544.253363-1-dan.scally@ideasonboard.com/
> Reviewed-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
> Tested-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
> Signed-off-by: Avichal Rakesh <arakesh@google.com>
> ---
> v1 -> v2: Rebased to ToT and reworded commit message.
> v2 -> v3: Fix email threading goof-up
> v3 -> v4: Address review comments & re-rebase to ToT
> v4 -> v5: Add Reviewed-by & Tested-by
> v5 -> v6: No change
> v6 -> v7: No change
> v7 -> v8: No change. Getting back in review queue
>
> drivers/usb/gadget/function/f_uvc.c | 11 +++++------
> drivers/usb/gadget/function/f_uvc.h | 2 +-
> drivers/usb/gadget/function/uvc.h | 2 +-
> drivers/usb/gadget/function/uvc_v4l2.c | 20 +++++++++++++++++---
> drivers/usb/gadget/function/uvc_video.c | 3 ++-
> 5 files changed, 26 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/usb/gadget/function/f_uvc.c b/drivers/usb/gadget/function/f_uvc.c
> index faa398109431..ae08341961eb 100644
> --- a/drivers/usb/gadget/function/f_uvc.c
> +++ b/drivers/usb/gadget/function/f_uvc.c
> @@ -263,10 +263,13 @@ uvc_function_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
> return 0;
> }
>
> -void uvc_function_setup_continue(struct uvc_device *uvc)
> +void uvc_function_setup_continue(struct uvc_device *uvc, int disable_ep)
> {
> struct usb_composite_dev *cdev = uvc->func.config->cdev;
>
> + if (disable_ep && uvc->video.ep)
> + usb_ep_disable(uvc->video.ep);
> +
> usb_composite_setup_continue(cdev);
> }
>
> @@ -337,15 +340,11 @@ uvc_function_set_alt(struct usb_function *f, unsigned interface, unsigned alt)
> if (uvc->state != UVC_STATE_STREAMING)
> return 0;
>
> - if (uvc->video.ep)
> - usb_ep_disable(uvc->video.ep);
> -
> memset(&v4l2_event, 0, sizeof(v4l2_event));
> v4l2_event.type = UVC_EVENT_STREAMOFF;
> v4l2_event_queue(&uvc->vdev, &v4l2_event);
>
> - uvc->state = UVC_STATE_CONNECTED;
> - return 0;
> + return USB_GADGET_DELAYED_STATUS;
>
> case 1:
> if (uvc->state != UVC_STATE_CONNECTED)
> diff --git a/drivers/usb/gadget/function/f_uvc.h b/drivers/usb/gadget/function/f_uvc.h
> index 1db972d4beeb..e7f9f13f14dc 100644
> --- a/drivers/usb/gadget/function/f_uvc.h
> +++ b/drivers/usb/gadget/function/f_uvc.h
> @@ -11,7 +11,7 @@
>
> struct uvc_device;
>
> -void uvc_function_setup_continue(struct uvc_device *uvc);
> +void uvc_function_setup_continue(struct uvc_device *uvc, int disale_ep);
>
> void uvc_function_connect(struct uvc_device *uvc);
>
> diff --git a/drivers/usb/gadget/function/uvc.h b/drivers/usb/gadget/function/uvc.h
> index 6751de8b63ad..989bc6b4e93d 100644
> --- a/drivers/usb/gadget/function/uvc.h
> +++ b/drivers/usb/gadget/function/uvc.h
> @@ -177,7 +177,7 @@ struct uvc_file_handle {
> * Functions
> */
>
> -extern void uvc_function_setup_continue(struct uvc_device *uvc);
> +extern void uvc_function_setup_continue(struct uvc_device *uvc, int disable_ep);
> extern void uvc_function_connect(struct uvc_device *uvc);
> extern void uvc_function_disconnect(struct uvc_device *uvc);
>
> diff --git a/drivers/usb/gadget/function/uvc_v4l2.c b/drivers/usb/gadget/function/uvc_v4l2.c
> index 3f0a9795c0d4..7cb8d027ff0c 100644
> --- a/drivers/usb/gadget/function/uvc_v4l2.c
> +++ b/drivers/usb/gadget/function/uvc_v4l2.c
> @@ -451,7 +451,7 @@ uvc_v4l2_streamon(struct file *file, void *fh, enum v4l2_buf_type type)
> * Complete the alternate setting selection setup phase now that
> * userspace is ready to provide video frames.
> */
> - uvc_function_setup_continue(uvc);
> + uvc_function_setup_continue(uvc, 0);
> uvc->state = UVC_STATE_STREAMING;
>
> return 0;
> @@ -463,11 +463,18 @@ uvc_v4l2_streamoff(struct file *file, void *fh, enum v4l2_buf_type type)
> struct video_device *vdev = video_devdata(file);
> struct uvc_device *uvc = video_get_drvdata(vdev);
> struct uvc_video *video = &uvc->video;
> + int ret = 0;
>
> if (type != video->queue.queue.type)
> return -EINVAL;
>
> - return uvcg_video_enable(video, 0);
> + uvc->state = UVC_STATE_CONNECTED;
> + ret = uvcg_video_enable(video, 0);
> + if (ret < 0)
> + return ret;
> +
> + uvc_function_setup_continue(uvc, 1);
> + return 0;
> }
>
> static int
> @@ -500,6 +507,14 @@ uvc_v4l2_subscribe_event(struct v4l2_fh *fh,
> static void uvc_v4l2_disable(struct uvc_device *uvc)
> {
> uvc_function_disconnect(uvc);
> + /*
> + * Drop uvc->state to CONNECTED if it was streaming before.
> + * This ensures that the usb_requests are no longer queued
> + * to the controller.
> + */
> + if (uvc->state == UVC_STATE_STREAMING)
> + uvc->state = UVC_STATE_CONNECTED;
> +
> uvcg_video_enable(&uvc->video, 0);
> uvcg_free_buffers(&uvc->video.queue);
> uvc->func_connected = false;
> @@ -647,4 +662,3 @@ const struct v4l2_file_operations uvc_v4l2_fops = {
> .get_unmapped_area = uvcg_v4l2_get_unmapped_area,
> #endif
> };
> -
> diff --git a/drivers/usb/gadget/function/uvc_video.c b/drivers/usb/gadget/function/uvc_video.c
> index 91af3b1ef0d4..c334802ac0a4 100644
> --- a/drivers/usb/gadget/function/uvc_video.c
> +++ b/drivers/usb/gadget/function/uvc_video.c
> @@ -384,13 +384,14 @@ static void uvcg_video_pump(struct work_struct *work)
> struct uvc_video_queue *queue = &video->queue;
> /* video->max_payload_size is only set when using bulk transfer */
> bool is_bulk = video->max_payload_size;
> + struct uvc_device *uvc = video->uvc;
> struct usb_request *req = NULL;
> struct uvc_buffer *buf;
> unsigned long flags;
> bool buf_done;
> int ret;
>
> - while (video->ep->enabled) {
> + while (uvc->state == UVC_STATE_STREAMING && video->ep->enabled) {
> /*
> * Retrieve the first available USB request, protected by the
> * request lock.
> --
> 2.42.0.758.gaed0368e0e-goog
Hey Greg,
Considering Laurent and Dan haven't responded, and Michael and I have
tested this change, would it be possible to merge this patch set
if the changes look OK to you? I don't think there are any outstanding
items to be done around these fixes.
Thank you!
- Avi.
On Thu, Oct 26, 2023 at 01:23:44PM -0700, Avichal Rakesh wrote: > Considering Laurent and Dan haven't responded, and Michael and I have > tested this change, would it be possible to merge this patch set > if the changes look OK to you? I don't think there are any outstanding > items to be done around these fixes. I would like their review first please. thanks, greg k-h
Good morning On 27/10/2023 11:51, Greg KH wrote: > On Thu, Oct 26, 2023 at 01:23:44PM -0700, Avichal Rakesh wrote: >> Considering Laurent and Dan haven't responded, and Michael and I have >> tested this change, would it be possible to merge this patch set >> if the changes look OK to you? I don't think there are any outstanding >> items to be done around these fixes. > I would like their review first please. Apologies for the delay - I am reviewing it now. > > thanks, > > greg k-h
Currently, the uvc gadget driver allocates all uvc_requests as one array
and deallocates them all when the video stream stops. This includes
de-allocating all the usb_requests associated with those uvc_requests.
This can lead to use-after-free issues if any of those de-allocated
usb_requests were still owned by the usb controller.
This patch is 1 of 2 patches addressing the use-after-free issue.
Instead of bulk allocating all uvc_requests as an array, this patch
allocates uvc_requests one at a time, which should allows for similar
granularity when deallocating the uvc_requests. This patch has no
functional changes other than allocating each uvc_request separately,
and similarly freeing each of them separately.
Link: https://lore.kernel.org/7cd81649-2795-45b6-8c10-b7df1055020d@google.com
Suggested-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Reviewed-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Tested-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Signed-off-by: Avichal Rakesh <arakesh@google.com>
---
v1 -> v2: Rebased to ToT
v2 -> v3: Fix email threading goof-up
v3 -> v4: Address review comments & re-rebase to ToT
v4 -> v5: Address more review comments. Add Reviewed-by & Tested-by.
v5 -> v6: No change
v6 -> v7: No change
v7 -> v8: No change. Getting back in review queue
drivers/usb/gadget/function/uvc.h | 3 +-
drivers/usb/gadget/function/uvc_video.c | 89 ++++++++++++++-----------
2 files changed, 52 insertions(+), 40 deletions(-)
diff --git a/drivers/usb/gadget/function/uvc.h b/drivers/usb/gadget/function/uvc.h
index 989bc6b4e93d..993694da0bbc 100644
--- a/drivers/usb/gadget/function/uvc.h
+++ b/drivers/usb/gadget/function/uvc.h
@@ -81,6 +81,7 @@ struct uvc_request {
struct sg_table sgt;
u8 header[UVCG_REQUEST_HEADER_LEN];
struct uvc_buffer *last_buf;
+ struct list_head list;
};
struct uvc_video {
@@ -102,7 +103,7 @@ struct uvc_video {
/* Requests */
unsigned int req_size;
- struct uvc_request *ureq;
+ struct list_head ureqs; /* all uvc_requests allocated by uvc_video */
struct list_head req_free;
spinlock_t req_lock;
diff --git a/drivers/usb/gadget/function/uvc_video.c b/drivers/usb/gadget/function/uvc_video.c
index c334802ac0a4..c180866c8e34 100644
--- a/drivers/usb/gadget/function/uvc_video.c
+++ b/drivers/usb/gadget/function/uvc_video.c
@@ -227,6 +227,24 @@ uvc_video_encode_isoc(struct usb_request *req, struct uvc_video *video,
* Request handling
*/
+static void
+uvc_video_free_request(struct uvc_request *ureq, struct usb_ep *ep)
+{
+ sg_free_table(&ureq->sgt);
+ if (ureq->req && ep) {
+ usb_ep_free_request(ep, ureq->req);
+ ureq->req = NULL;
+ }
+
+ kfree(ureq->req_buffer);
+ ureq->req_buffer = NULL;
+
+ if (!list_empty(&ureq->list))
+ list_del_init(&ureq->list);
+
+ kfree(ureq);
+}
+
static int uvcg_video_ep_queue(struct uvc_video *video, struct usb_request *req)
{
int ret;
@@ -293,27 +311,12 @@ uvc_video_complete(struct usb_ep *ep, struct usb_request *req)
static int
uvc_video_free_requests(struct uvc_video *video)
{
- unsigned int i;
-
- if (video->ureq) {
- for (i = 0; i < video->uvc_num_requests; ++i) {
- sg_free_table(&video->ureq[i].sgt);
+ struct uvc_request *ureq, *temp;
- if (video->ureq[i].req) {
- usb_ep_free_request(video->ep, video->ureq[i].req);
- video->ureq[i].req = NULL;
- }
-
- if (video->ureq[i].req_buffer) {
- kfree(video->ureq[i].req_buffer);
- video->ureq[i].req_buffer = NULL;
- }
- }
-
- kfree(video->ureq);
- video->ureq = NULL;
- }
+ list_for_each_entry_safe(ureq, temp, &video->ureqs, list)
+ uvc_video_free_request(ureq, video->ep);
+ INIT_LIST_HEAD(&video->ureqs);
INIT_LIST_HEAD(&video->req_free);
video->req_size = 0;
return 0;
@@ -322,6 +325,7 @@ uvc_video_free_requests(struct uvc_video *video)
static int
uvc_video_alloc_requests(struct uvc_video *video)
{
+ struct uvc_request *ureq;
unsigned int req_size;
unsigned int i;
int ret = -ENOMEM;
@@ -332,29 +336,34 @@ uvc_video_alloc_requests(struct uvc_video *video)
* max_t(unsigned int, video->ep->maxburst, 1)
* (video->ep->mult);
- video->ureq = kcalloc(video->uvc_num_requests, sizeof(struct uvc_request), GFP_KERNEL);
- if (video->ureq == NULL)
- return -ENOMEM;
+ INIT_LIST_HEAD(&video->ureqs);
+ for (i = 0; i < video->uvc_num_requests; i++) {
+ ureq = kzalloc(sizeof(struct uvc_request), GFP_KERNEL);
+ if (ureq == NULL)
+ goto error;
+
+ INIT_LIST_HEAD(&ureq->list);
+
+ list_add_tail(&ureq->list, &video->ureqs);
- for (i = 0; i < video->uvc_num_requests; ++i) {
- video->ureq[i].req_buffer = kmalloc(req_size, GFP_KERNEL);
- if (video->ureq[i].req_buffer == NULL)
+ ureq->req_buffer = kmalloc(req_size, GFP_KERNEL);
+ if (ureq->req_buffer == NULL)
goto error;
- video->ureq[i].req = usb_ep_alloc_request(video->ep, GFP_KERNEL);
- if (video->ureq[i].req == NULL)
+ ureq->req = usb_ep_alloc_request(video->ep, GFP_KERNEL);
+ if (ureq->req == NULL)
goto error;
- video->ureq[i].req->buf = video->ureq[i].req_buffer;
- video->ureq[i].req->length = 0;
- video->ureq[i].req->complete = uvc_video_complete;
- video->ureq[i].req->context = &video->ureq[i];
- video->ureq[i].video = video;
- video->ureq[i].last_buf = NULL;
+ ureq->req->buf = ureq->req_buffer;
+ ureq->req->length = 0;
+ ureq->req->complete = uvc_video_complete;
+ ureq->req->context = ureq;
+ ureq->video = video;
+ ureq->last_buf = NULL;
- list_add_tail(&video->ureq[i].req->list, &video->req_free);
+ list_add_tail(&ureq->req->list, &video->req_free);
/* req_size/PAGE_SIZE + 1 for overruns and + 1 for header */
- sg_alloc_table(&video->ureq[i].sgt,
+ sg_alloc_table(&ureq->sgt,
DIV_ROUND_UP(req_size - UVCG_REQUEST_HEADER_LEN,
PAGE_SIZE) + 2, GFP_KERNEL);
}
@@ -489,8 +498,8 @@ static void uvcg_video_pump(struct work_struct *work)
*/
int uvcg_video_enable(struct uvc_video *video, int enable)
{
- unsigned int i;
int ret;
+ struct uvc_request *ureq;
if (video->ep == NULL) {
uvcg_info(&video->uvc->func,
@@ -502,9 +511,10 @@ int uvcg_video_enable(struct uvc_video *video, int enable)
cancel_work_sync(&video->pump);
uvcg_queue_cancel(&video->queue, 0);
- for (i = 0; i < video->uvc_num_requests; ++i)
- if (video->ureq && video->ureq[i].req)
- usb_ep_dequeue(video->ep, video->ureq[i].req);
+ list_for_each_entry(ureq, &video->ureqs, list) {
+ if (ureq->req)
+ usb_ep_dequeue(video->ep, ureq->req);
+ }
uvc_video_free_requests(video);
uvcg_queue_enable(&video->queue, 0);
@@ -536,6 +546,7 @@ int uvcg_video_enable(struct uvc_video *video, int enable)
*/
int uvcg_video_init(struct uvc_video *video, struct uvc_device *uvc)
{
+ INIT_LIST_HEAD(&video->ureqs);
INIT_LIST_HEAD(&video->req_free);
spin_lock_init(&video->req_lock);
INIT_WORK(&video->pump, uvcg_video_pump);
--
2.42.0.758.gaed0368e0e-googThis patch refactors the video disable logic in uvcg_video_enable
into its own separate function 'uvcg_video_disable'.
Suggested-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Signed-off-by: Avichal Rakesh <arakesh@google.com>
---
v6: Introduced this patch to make the next one easier to review
v6 -> v7: Add Suggested-by
v7 -> v8: No change. Getting back in review queue
drivers/usb/gadget/function/uvc_video.c | 37 +++++++++++++++----------
1 file changed, 23 insertions(+), 14 deletions(-)
diff --git a/drivers/usb/gadget/function/uvc_video.c b/drivers/usb/gadget/function/uvc_video.c
index c180866c8e34..80b8eaea2d39 100644
--- a/drivers/usb/gadget/function/uvc_video.c
+++ b/drivers/usb/gadget/function/uvc_video.c
@@ -493,13 +493,33 @@ static void uvcg_video_pump(struct work_struct *work)
return;
}
+/*
+ * Disable video stream
+ */
+static int
+uvcg_video_disable(struct uvc_video *video)
+{
+ struct uvc_request *ureq;
+
+ cancel_work_sync(&video->pump);
+ uvcg_queue_cancel(&video->queue, 0);
+
+ list_for_each_entry(ureq, &video->ureqs, list) {
+ if (ureq->req)
+ usb_ep_dequeue(video->ep, ureq->req);
+ }
+
+ uvc_video_free_requests(video);
+ uvcg_queue_enable(&video->queue, 0);
+ return 0;
+}
+
/*
* Enable or disable the video stream.
*/
int uvcg_video_enable(struct uvc_video *video, int enable)
{
int ret;
- struct uvc_request *ureq;
if (video->ep == NULL) {
uvcg_info(&video->uvc->func,
@@ -507,19 +527,8 @@ int uvcg_video_enable(struct uvc_video *video, int enable)
return -ENODEV;
}
- if (!enable) {
- cancel_work_sync(&video->pump);
- uvcg_queue_cancel(&video->queue, 0);
-
- list_for_each_entry(ureq, &video->ureqs, list) {
- if (ureq->req)
- usb_ep_dequeue(video->ep, ureq->req);
- }
-
- uvc_video_free_requests(video);
- uvcg_queue_enable(&video->queue, 0);
- return 0;
- }
+ if (!enable)
+ return uvcg_video_disable(video);
if ((ret = uvcg_queue_enable(&video->queue, 1)) < 0)
return ret;
--
2.42.0.758.gaed0368e0e-googCurrently, the uvc gadget driver allocates all uvc_requests as one array
and deallocates them all when the video stream stops. This includes
de-allocating all the usb_requests associated with those uvc_requests.
This can lead to use-after-free issues if any of those de-allocated
usb_requests were still owned by the usb controller.
This is patch 2 of 2 in fixing the use-after-free issue. It adds a new
flag to uvc_video to track when frames and requests should be flowing.
When disabling the video stream, the flag is tripped and, instead
of de-allocating all uvc_requests and usb_requests, the gadget
driver only de-allocates those usb_requests that are currently
owned by it (as present in req_free). Other usb_requests are left
untouched until their completion handler is called which takes care
of freeing the usb_request and its corresponding uvc_request.
Now that uvc_video does not depends on uvc->state, this patch removes
unnecessary upates to uvc->state that were made to accommodate uvc_video
logic. This should ensure that uvc gadget driver never accidentally
de-allocates a usb_request that it doesn't own.
Link: https://lore.kernel.org/7cd81649-2795-45b6-8c10-b7df1055020d@google.com
Suggested-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Reviewed-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Tested-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Signed-off-by: Avichal Rakesh <arakesh@google.com>
---
v1 -> v2: Rebased to ToT, and fixed deadlock reported in
https://lore.kernel.org/all/ZRv2UnKztgyqk2pt@pengutronix.de/
v2 -> v3: Fix email threading goof-up
v3 -> v4: re-rebase to ToT & moved to a uvc_video level lock
as discussed in
https://lore.kernel.org/b14b296f-2e08-4edf-aeea-1c5b621e2d0c@google.com/
v4 -> v5: Address review comments. Add Reviewed-by & Tested-by.
v5 -> v6: Added another patch before this one to make uvcg_video_disable
easier to review.
v6 -> v7: Fix warning reported in
https://lore.kernel.org/202310200457.GwPPFuHX-lkp@intel.com/
v7 -> v8: No change. Getting back in review queue
drivers/usb/gadget/function/uvc.h | 1 +
drivers/usb/gadget/function/uvc_v4l2.c | 12 +--
drivers/usb/gadget/function/uvc_video.c | 128 ++++++++++++++++++++----
3 files changed, 111 insertions(+), 30 deletions(-)
diff --git a/drivers/usb/gadget/function/uvc.h b/drivers/usb/gadget/function/uvc.h
index 993694da0bbc..be0d012aa244 100644
--- a/drivers/usb/gadget/function/uvc.h
+++ b/drivers/usb/gadget/function/uvc.h
@@ -102,6 +102,7 @@ struct uvc_video {
unsigned int uvc_num_requests;
/* Requests */
+ bool is_enabled; /* tracks whether video stream is enabled */
unsigned int req_size;
struct list_head ureqs; /* all uvc_requests allocated by uvc_video */
struct list_head req_free;
diff --git a/drivers/usb/gadget/function/uvc_v4l2.c b/drivers/usb/gadget/function/uvc_v4l2.c
index 7cb8d027ff0c..f4d2e24835d4 100644
--- a/drivers/usb/gadget/function/uvc_v4l2.c
+++ b/drivers/usb/gadget/function/uvc_v4l2.c
@@ -451,8 +451,8 @@ uvc_v4l2_streamon(struct file *file, void *fh, enum v4l2_buf_type type)
* Complete the alternate setting selection setup phase now that
* userspace is ready to provide video frames.
*/
- uvc_function_setup_continue(uvc, 0);
uvc->state = UVC_STATE_STREAMING;
+ uvc_function_setup_continue(uvc, 0);
return 0;
}
@@ -468,11 +468,11 @@ uvc_v4l2_streamoff(struct file *file, void *fh, enum v4l2_buf_type type)
if (type != video->queue.queue.type)
return -EINVAL;
- uvc->state = UVC_STATE_CONNECTED;
ret = uvcg_video_enable(video, 0);
if (ret < 0)
return ret;
+ uvc->state = UVC_STATE_CONNECTED;
uvc_function_setup_continue(uvc, 1);
return 0;
}
@@ -507,14 +507,6 @@ uvc_v4l2_subscribe_event(struct v4l2_fh *fh,
static void uvc_v4l2_disable(struct uvc_device *uvc)
{
uvc_function_disconnect(uvc);
- /*
- * Drop uvc->state to CONNECTED if it was streaming before.
- * This ensures that the usb_requests are no longer queued
- * to the controller.
- */
- if (uvc->state == UVC_STATE_STREAMING)
- uvc->state = UVC_STATE_CONNECTED;
-
uvcg_video_enable(&uvc->video, 0);
uvcg_free_buffers(&uvc->video.queue);
uvc->func_connected = false;
diff --git a/drivers/usb/gadget/function/uvc_video.c b/drivers/usb/gadget/function/uvc_video.c
index 80b8eaea2d39..ab3f02054e85 100644
--- a/drivers/usb/gadget/function/uvc_video.c
+++ b/drivers/usb/gadget/function/uvc_video.c
@@ -227,6 +227,9 @@ uvc_video_encode_isoc(struct usb_request *req, struct uvc_video *video,
* Request handling
*/
+/*
+ * Must be called with req_lock held as it modifies the list ureq is held in
+ */
static void
uvc_video_free_request(struct uvc_request *ureq, struct usb_ep *ep)
{
@@ -271,9 +274,25 @@ uvc_video_complete(struct usb_ep *ep, struct usb_request *req)
struct uvc_request *ureq = req->context;
struct uvc_video *video = ureq->video;
struct uvc_video_queue *queue = &video->queue;
- struct uvc_device *uvc = video->uvc;
+ struct uvc_buffer *last_buf = NULL;
unsigned long flags;
+ spin_lock_irqsave(&video->req_lock, flags);
+ if (!video->is_enabled) {
+ /*
+ * When is_enabled is false, uvc_video_disable ensures that
+ * in-flight uvc_buffers are returned, so we can safely
+ * call free_request without worrying about last_buf.
+ */
+ uvc_video_free_request(ureq, ep);
+ spin_unlock_irqrestore(&video->req_lock, flags);
+ return;
+ }
+
+ last_buf = ureq->last_buf;
+ ureq->last_buf = NULL;
+ spin_unlock_irqrestore(&video->req_lock, flags);
+
switch (req->status) {
case 0:
break;
@@ -295,17 +314,26 @@ uvc_video_complete(struct usb_ep *ep, struct usb_request *req)
uvcg_queue_cancel(queue, 0);
}
- if (ureq->last_buf) {
- uvcg_complete_buffer(&video->queue, ureq->last_buf);
- ureq->last_buf = NULL;
+ if (last_buf) {
+ spin_lock_irqsave(&queue->irqlock, flags);
+ uvcg_complete_buffer(&video->queue, last_buf);
+ spin_unlock_irqrestore(&queue->irqlock, flags);
}
spin_lock_irqsave(&video->req_lock, flags);
- list_add_tail(&req->list, &video->req_free);
- spin_unlock_irqrestore(&video->req_lock, flags);
-
- if (uvc->state == UVC_STATE_STREAMING)
+ /*
+ * Video stream might have been disabled while we were
+ * processing the current usb_request. So make sure
+ * we're still streaming before queueing the usb_request
+ * back to req_free
+ */
+ if (video->is_enabled) {
+ list_add_tail(&req->list, &video->req_free);
queue_work(video->async_wq, &video->pump);
+ } else {
+ uvc_video_free_request(ureq, ep);
+ }
+ spin_unlock_irqrestore(&video->req_lock, flags);
}
static int
@@ -393,20 +421,22 @@ static void uvcg_video_pump(struct work_struct *work)
struct uvc_video_queue *queue = &video->queue;
/* video->max_payload_size is only set when using bulk transfer */
bool is_bulk = video->max_payload_size;
- struct uvc_device *uvc = video->uvc;
struct usb_request *req = NULL;
struct uvc_buffer *buf;
unsigned long flags;
bool buf_done;
int ret;
- while (uvc->state == UVC_STATE_STREAMING && video->ep->enabled) {
+ while (true) {
+ if (!video->ep->enabled)
+ return;
+
/*
- * Retrieve the first available USB request, protected by the
- * request lock.
+ * Check is_enabled and retrieve the first available USB
+ * request, protected by the request lock.
*/
spin_lock_irqsave(&video->req_lock, flags);
- if (list_empty(&video->req_free)) {
+ if (!video->is_enabled || list_empty(&video->req_free)) {
spin_unlock_irqrestore(&video->req_lock, flags);
return;
}
@@ -488,9 +518,11 @@ static void uvcg_video_pump(struct work_struct *work)
return;
spin_lock_irqsave(&video->req_lock, flags);
- list_add_tail(&req->list, &video->req_free);
+ if (video->is_enabled)
+ list_add_tail(&req->list, &video->req_free);
+ else
+ uvc_video_free_request(req->context, video->ep);
spin_unlock_irqrestore(&video->req_lock, flags);
- return;
}
/*
@@ -499,17 +531,64 @@ static void uvcg_video_pump(struct work_struct *work)
static int
uvcg_video_disable(struct uvc_video *video)
{
- struct uvc_request *ureq;
+ unsigned long flags;
+ struct list_head inflight_bufs;
+ struct usb_request *req, *temp;
+ struct uvc_buffer *buf, *btemp;
+ struct uvc_request *ureq, *utemp;
+
+ INIT_LIST_HEAD(&inflight_bufs);
+ spin_lock_irqsave(&video->req_lock, flags);
+ video->is_enabled = false;
+
+ /*
+ * Remove any in-flight buffers from the uvc_requests
+ * because we want to return them before cancelling the
+ * queue. This ensures that we aren't stuck waiting for
+ * all complete callbacks to come through before disabling
+ * vb2 queue.
+ */
+ list_for_each_entry(ureq, &video->ureqs, list) {
+ if (ureq->last_buf) {
+ list_add_tail(&ureq->last_buf->queue, &inflight_bufs);
+ ureq->last_buf = NULL;
+ }
+ }
+ spin_unlock_irqrestore(&video->req_lock, flags);
cancel_work_sync(&video->pump);
uvcg_queue_cancel(&video->queue, 0);
- list_for_each_entry(ureq, &video->ureqs, list) {
- if (ureq->req)
- usb_ep_dequeue(video->ep, ureq->req);
+ spin_lock_irqsave(&video->req_lock, flags);
+ /*
+ * Remove all uvc_reqeusts from ureqs with list_del_init
+ * This lets uvc_video_free_request correctly identify
+ * if the uvc_request is attached to a list or not when freeing
+ * memory.
+ */
+ list_for_each_entry_safe(ureq, utemp, &video->ureqs, list)
+ list_del_init(&ureq->list);
+
+ list_for_each_entry_safe(req, temp, &video->req_free, list) {
+ list_del(&req->list);
+ uvc_video_free_request(req->context, video->ep);
}
- uvc_video_free_requests(video);
+ INIT_LIST_HEAD(&video->ureqs);
+ INIT_LIST_HEAD(&video->req_free);
+ video->req_size = 0;
+ spin_unlock_irqrestore(&video->req_lock, flags);
+
+ /*
+ * Return all the video buffers before disabling the queue.
+ */
+ spin_lock_irqsave(&video->queue.irqlock, flags);
+ list_for_each_entry_safe(buf, btemp, &inflight_bufs, queue) {
+ list_del(&buf->queue);
+ uvcg_complete_buffer(&video->queue, buf);
+ }
+ spin_unlock_irqrestore(&video->queue.irqlock, flags);
+
uvcg_queue_enable(&video->queue, 0);
return 0;
}
@@ -530,6 +609,14 @@ int uvcg_video_enable(struct uvc_video *video, int enable)
if (!enable)
return uvcg_video_disable(video);
+ /*
+ * Safe to access request related fields without req_lock because
+ * this is the only thread currently active, and no other
+ * request handling thread will become active until this function
+ * returns.
+ */
+ video->is_enabled = true;
+
if ((ret = uvcg_queue_enable(&video->queue, 1)) < 0)
return ret;
@@ -555,6 +642,7 @@ int uvcg_video_enable(struct uvc_video *video, int enable)
*/
int uvcg_video_init(struct uvc_video *video, struct uvc_device *uvc)
{
+ video->is_enabled = false;
INIT_LIST_HEAD(&video->ureqs);
INIT_LIST_HEAD(&video->req_free);
spin_lock_init(&video->req_lock);
--
2.42.0.758.gaed0368e0e-goog© 2016 - 2025 Red Hat, Inc.