This patch has been already merged in stable https://web.git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/drivers/media/usb/uvc?h=linux-6.6.y&id=4dbaa738c583a0e947803c69e8996e88cf98d971 On Mon, 10 Feb 2025 at 16:12, <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > > The patch below does not apply to the 6.6-stable tree. > If someone wants it applied there, or to any other stable or longterm > tree, then please email the backport, including the original git commit > id to <stable@xxxxxxxxxxxxxxx>. > > To reproduce the conflict and resubmit, you may use the following commands: > > git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y > git checkout FETCH_HEAD > git cherry-pick -x 221cd51efe4565501a3dbf04cc011b537dcce7fb > # <resolve conflicts, build, test, etc.> > git commit -s > git send-email --to '<stable@xxxxxxxxxxxxxxx>' --in-reply-to '2025021035-alarm-cautious-b382@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. > > Possible dependencies: > > > > thanks, > > greg k-h > > ------------------ original commit in Linus's tree ------------------ > > From 221cd51efe4565501a3dbf04cc011b537dcce7fb Mon Sep 17 00:00:00 2001 > From: Ricardo Ribalda <ribalda@xxxxxxxxxxxx> > Date: Tue, 3 Dec 2024 21:20:10 +0000 > Subject: [PATCH] media: uvcvideo: Remove dangling pointers > > When an async control is written, we copy a pointer to the file handle > that started the operation. That pointer will be used when the device is > done. Which could be anytime in the future. > > If the user closes that file descriptor, its structure will be freed, > and there will be one dangling pointer per pending async control, that > the driver will try to use. > > Clean all the dangling pointers during release(). > > To avoid adding a performance penalty in the most common case (no async > operation), a counter has been introduced with some logic to make sure > that it is properly handled. > > Cc: stable@xxxxxxxxxxxxxxx > Fixes: e5225c820c05 ("media: uvcvideo: Send a control event when a Control Change interrupt arrives") > Reviewed-by: Hans de Goede <hdegoede@xxxxxxxxxx> > Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx> > Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> > Link: https://lore.kernel.org/r/20241203-uvc-fix-async-v6-3-26c867231118@xxxxxxxxxxxx > Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> > Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx> > > diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c > index b05b84887e51..4837d8df9c03 100644 > --- a/drivers/media/usb/uvc/uvc_ctrl.c > +++ b/drivers/media/usb/uvc/uvc_ctrl.c > @@ -1579,6 +1579,40 @@ static void uvc_ctrl_send_slave_event(struct uvc_video_chain *chain, > uvc_ctrl_send_event(chain, handle, ctrl, mapping, val, changes); > } > > +static void uvc_ctrl_set_handle(struct uvc_fh *handle, struct uvc_control *ctrl, > + struct uvc_fh *new_handle) > +{ > + lockdep_assert_held(&handle->chain->ctrl_mutex); > + > + if (new_handle) { > + if (ctrl->handle) > + dev_warn_ratelimited(&handle->stream->dev->udev->dev, > + "UVC non compliance: Setting an async control with a pending operation."); > + > + if (new_handle == ctrl->handle) > + return; > + > + if (ctrl->handle) { > + WARN_ON(!ctrl->handle->pending_async_ctrls); > + if (ctrl->handle->pending_async_ctrls) > + ctrl->handle->pending_async_ctrls--; > + } > + > + ctrl->handle = new_handle; > + handle->pending_async_ctrls++; > + return; > + } > + > + /* Cannot clear the handle for a control not owned by us.*/ > + if (WARN_ON(ctrl->handle != handle)) > + return; > + > + ctrl->handle = NULL; > + if (WARN_ON(!handle->pending_async_ctrls)) > + return; > + handle->pending_async_ctrls--; > +} > + > void uvc_ctrl_status_event(struct uvc_video_chain *chain, > struct uvc_control *ctrl, const u8 *data) > { > @@ -1589,7 +1623,8 @@ void uvc_ctrl_status_event(struct uvc_video_chain *chain, > mutex_lock(&chain->ctrl_mutex); > > handle = ctrl->handle; > - ctrl->handle = NULL; > + if (handle) > + uvc_ctrl_set_handle(handle, ctrl, NULL); > > list_for_each_entry(mapping, &ctrl->info.mappings, list) { > s32 value = __uvc_ctrl_get_value(mapping, data); > @@ -1863,7 +1898,7 @@ static int uvc_ctrl_commit_entity(struct uvc_device *dev, > > if (!rollback && handle && > ctrl->info.flags & UVC_CTRL_FLAG_ASYNCHRONOUS) > - ctrl->handle = handle; > + uvc_ctrl_set_handle(handle, ctrl, handle); > } > > return 0; > @@ -2772,6 +2807,26 @@ int uvc_ctrl_init_device(struct uvc_device *dev) > return 0; > } > > +void uvc_ctrl_cleanup_fh(struct uvc_fh *handle) > +{ > + struct uvc_entity *entity; > + > + guard(mutex)(&handle->chain->ctrl_mutex); > + > + if (!handle->pending_async_ctrls) > + return; > + > + list_for_each_entry(entity, &handle->chain->dev->entities, list) { > + for (unsigned int i = 0; i < entity->ncontrols; ++i) { > + if (entity->controls[i].handle != handle) > + continue; > + uvc_ctrl_set_handle(handle, &entity->controls[i], NULL); > + } > + } > + > + WARN_ON(handle->pending_async_ctrls); > +} > + > /* > * Cleanup device controls. > */ > diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c > index dee6feeba274..93c6cdb23881 100644 > --- a/drivers/media/usb/uvc/uvc_v4l2.c > +++ b/drivers/media/usb/uvc/uvc_v4l2.c > @@ -671,6 +671,8 @@ static int uvc_v4l2_release(struct file *file) > > uvc_dbg(stream->dev, CALLS, "%s\n", __func__); > > + uvc_ctrl_cleanup_fh(handle); > + > /* Only free resources if this is a privileged handle. */ > if (uvc_has_privileges(handle)) > uvc_queue_release(&stream->queue); > diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h > index 965a789ed03e..5690cfd61e23 100644 > --- a/drivers/media/usb/uvc/uvcvideo.h > +++ b/drivers/media/usb/uvc/uvcvideo.h > @@ -338,7 +338,11 @@ struct uvc_video_chain { > struct uvc_entity *processing; /* Processing unit */ > struct uvc_entity *selector; /* Selector unit */ > > - struct mutex ctrl_mutex; /* Protects ctrl.info */ > + struct mutex ctrl_mutex; /* > + * Protects ctrl.info, > + * ctrl.handle and > + * uvc_fh.pending_async_ctrls > + */ > > struct v4l2_prio_state prio; /* V4L2 priority state */ > u32 caps; /* V4L2 chain-wide caps */ > @@ -613,6 +617,7 @@ struct uvc_fh { > struct uvc_video_chain *chain; > struct uvc_streaming *stream; > enum uvc_handle_state state; > + unsigned int pending_async_ctrls; > }; > > struct uvc_driver { > @@ -798,6 +803,8 @@ int uvc_ctrl_is_accessible(struct uvc_video_chain *chain, u32 v4l2_id, > int uvc_xu_ctrl_query(struct uvc_video_chain *chain, > struct uvc_xu_control_query *xqry); > > +void uvc_ctrl_cleanup_fh(struct uvc_fh *handle); > + > /* Utility functions */ > struct usb_host_endpoint *uvc_find_endpoint(struct usb_host_interface *alts, > u8 epaddr); > -- Ricardo Ribalda
