kernel/linux.git/drivers/usb/gadget/function/f_uvc.c, branch v5.10.264

usb: gadget: uvc: fix NULL pointer dereference during unbind race

2026-04-18T08:31:16+00:00

[ Upstream commit eba2936bbe6b752a31725a9eb5c674ecbf21ee7d ] Commit b81ac4395bbe ("usb: gadget: uvc: allow for application to cleanly shutdown") introduced two stages of synchronization waits totaling 1500ms in uvc_function_unbind() to prevent several types of kernel panics. However, this timing-based approach is insufficient during power management (PM) transitions. When the PM subsystem starts freezing user space processes, the wait_event_interruptible_timeout() is aborted early, which allows the unbind thread to proceed and nullify the gadget pointer (cdev->gadget = NULL): [ 814.123447][ T947] configfs-gadget.g1 gadget.0: uvc: uvc_function_unbind() [ 814.178583][ T3173] PM: suspend entry (deep) [ 814.192487][ T3173] Freezing user space processes [ 814.197668][ T947] configfs-gadget.g1 gadget.0: uvc: uvc_function_unbind no clean disconnect, wait for release When the PM subsystem resumes or aborts the suspend and tasks are restarted, the V4L2 release path is executed and attempts to access the already nullified gadget pointer, triggering a kernel panic: [ 814.292597][ C0] PM: pm_system_irq_wakeup: 479 triggered dhdpcie_host_wake [ 814.386727][ T3173] Restarting tasks ... [ 814.403522][ T4558] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000030 [ 814.404021][ T4558] pc : usb_gadget_deactivate+0x14/0xf4 [ 814.404031][ T4558] lr : usb_function_deactivate+0x54/0x94 [ 814.404078][ T4558] Call trace: [ 814.404080][ T4558] usb_gadget_deactivate+0x14/0xf4 [ 814.404083][ T4558] usb_function_deactivate+0x54/0x94 [ 814.404087][ T4558] uvc_function_disconnect+0x1c/0x5c [ 814.404092][ T4558] uvc_v4l2_release+0x44/0xac [ 814.404095][ T4558] v4l2_release+0xcc/0x130 Address the race condition and NULL pointer dereference by: 1. State Synchronization (flag + mutex) Introduce a 'func_unbound' flag in struct uvc_device. This allows uvc_function_disconnect() to safely skip accessing the nullified cdev->gadget pointer. As suggested by Alan Stern, this flag is protected by a new mutex (uvc->lock) to ensure proper memory ordering and prevent instruction reordering or speculative loads. This mutex is also used to protect 'func_connected' for consistent state management. 2. Explicit Synchronization (completion) Use a completion to synchronize uvc_function_unbind() with the uvc_vdev_release() callback. This prevents Use-After-Free (UAF) by ensuring struct uvc_device is freed after all video device resources are released. Fixes: b81ac4395bbe ("usb: gadget: uvc: allow for application to cleanly shutdown") Cc: stable Suggested-by: Alan Stern Suggested-by: Greg Kroah-Hartman Signed-off-by: Jimmy Hu Link: https://patch.msgid.link/20260320065427.1374555-1-hhhuuu@google.com Signed-off-by: Greg Kroah-Hartman [ replaced guard()/scoped_guard() macros ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

usb: gadget: uvc: Prevent buffer overflow in setup handler

2022-12-21T16:32:06+00:00

commit 4c92670b16727365699fe4b19ed32013bab2c107 upstream. Setup function uvc_function_setup permits control transfer requests with up to 64 bytes of payload (UVC_MAX_REQUEST_SIZE), data stage handler for OUT transfer uses memcpy to copy req->actual bytes to uvc_event->data.data array of size 60. This may result in an overflow of 4 bytes. Fixes: cdda479f15cd ("USB gadget: video class function driver") Cc: stable Reviewed-by: Laurent Pinchart Reviewed-by: Daniel Scally Signed-off-by: Szymon Heidrich Link: https://lore.kernel.org/r/20221206141301.51305-1-szymon.heidrich@gmail.com Signed-off-by: Greg Kroah-Hartman

usb: gadget: uvc: allow for application to cleanly shutdown

2022-05-18T08:23:48+00:00

commit b81ac4395bbeaf36e078dea1a48c02dd97b76235 upstream. Several types of kernel panics can occur due to timing during the uvc gadget removal. This appears to be a problem with gadget resources being managed by both the client application's v4l2 open/close and the UDC gadget bind/unbind. Since the concept of USB_GADGET_DELAYED_STATUS doesn't exist for unbind, add a wait to allow for the application to close out. Some examples of the panics that can occur are: <1>[ 1147.652313] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000028 <4>[ 1147.652510] Call trace: <4>[ 1147.652514] usb_gadget_disconnect+0x74/0x1f0 <4>[ 1147.652516] usb_gadget_deactivate+0x38/0x168 <4>[ 1147.652520] usb_function_deactivate+0x54/0x90 <4>[ 1147.652524] uvc_function_disconnect+0x14/0x38 <4>[ 1147.652527] uvc_v4l2_release+0x34/0xa0 <4>[ 1147.652537] __fput+0xdc/0x2c0 <4>[ 1147.652540] ____fput+0x10/0x1c <4>[ 1147.652545] task_work_run+0xe4/0x12c <4>[ 1147.652549] do_notify_resume+0x108/0x168 <1>[ 282.950561][ T1472] Unable to handle kernel NULL pointer dereference at virtual address 00000000000005b8 <6>[ 282.953111][ T1472] Call trace: <6>[ 282.953121][ T1472] usb_function_deactivate+0x54/0xd4 <6>[ 282.953134][ T1472] uvc_v4l2_release+0xac/0x1e4 <6>[ 282.953145][ T1472] v4l2_release+0x134/0x1f0 <6>[ 282.953167][ T1472] __fput+0xf4/0x428 <6>[ 282.953178][ T1472] ____fput+0x14/0x24 <6>[ 282.953193][ T1472] task_work_run+0xac/0x130 <3>[ 213.410077][ T29] configfs-gadget gadget: uvc: Failed to queue request (-108). <1>[ 213.410116][ T29] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000003 <6>[ 213.413460][ T29] Call trace: <6>[ 213.413474][ T29] uvcg_video_pump+0x1f0/0x384 <6>[ 213.413489][ T29] process_one_work+0x2a4/0x544 <6>[ 213.413502][ T29] worker_thread+0x350/0x784 <6>[ 213.413515][ T29] kthread+0x2ac/0x320 <6>[ 213.413528][ T29] ret_from_fork+0x10/0x30 Signed-off-by: Dan Vacura Cc: stable Link: https://lore.kernel.org/r/20220503201039.71720-1-w36195@motorola.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman

usb: gadget: uvc: rename function to be more consistent

2022-05-18T08:23:48+00:00

commit e6bab2b66329b40462fb1bed6f98bc3fcf543a1c upstream. When enabling info debugging for the uvc gadget, the bind and unbind infos use different formats. Change the unbind to visually match the bind. Reviewed-by: Laurent Pinchart Reviewed-by: Paul Elder Signed-off-by: Michael Tretter Signed-off-by: Michael Grzeschik Link: https://lore.kernel.org/r/20211017215017.18392-3-m.grzeschik@pengutronix.de Signed-off-by: Greg Kroah-Hartman

usb: webcam: Invalid size of Processing Unit Descriptor

2021-05-11T12:47:17+00:00

[ Upstream commit 6a154ec9ef6762c774cd2b50215c7a8f0f08a862 ] According with USB Device Class Definition for Video Device the Processing Unit Descriptor bLength should be 12 (10 + bmControlSize), but it has 11. Invalid length caused that Processing Unit Descriptor Test Video form CV tool failed. To fix this issue patch adds bmVideoStandards into uvc_processing_unit_descriptor structure. The bmVideoStandards field was added in UVC 1.1 and it wasn't part of UVC 1.0a. Reviewed-by: Laurent Pinchart Signed-off-by: Pawel Laszczak Reviewed-by: Peter Chen Link: https://lore.kernel.org/r/20210315071748.29706-1-pawell@gli-login.cadence.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

usb: gadget: uvc: add bInterval checking for HS mode

2021-05-11T12:47:16+00:00

[ Upstream commit 26adde04acdff14a1f28d4a5dce46a8513a3038b ] Patch adds extra checking for bInterval passed by configfs. The 5.6.4 chapter of USB Specification (rev. 2.0) say: "A high-bandwidth endpoint must specify a period of 1x125 µs (i.e., a bInterval value of 1)." The issue was observed during testing UVC class on CV. I treat this change as improvement because we can control bInterval by configfs. Reviewed-by: Peter Chen Reviewed-by: Laurent Pinchart Signed-off-by: Pawel Laszczak Link: https://lore.kernel.org/r/20210308125338.4824-1-pawell@gli-login.cadence.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

usb: gadget: uvc: Fix the wrong v4l2_device_unregister call

2020-10-02T06:57:45+00:00

If an error occurred before calling the 'v4l2_device_register' func, and then goto error, but no need to call 'v4l2_device_unregister' func. Signed-off-by: Zqiang Signed-off-by: Felipe Balbi

media: gadget: uvc: rename VFL_TYPE_GRABBER to _VIDEO

2020-02-24T15:52:45+00:00

'GRABBER' is a weird name, all other types map to the /dev device names. Rename to 'VIDEO' to be consistent with the other types. Signed-off-by: Hans Verkuil Reviewed-by: Laurent Pinchart Signed-off-by: Mauro Carvalho Chehab

media: usb/gadget/f_uvc: set device_caps in struct video_device

2019-06-05T12:47:44+00:00

Instead of filling in the struct v4l2_capability device_caps field, fill in the struct video_device device_caps field. That way the V4L2 core knows what the capabilities of the video device are. But this only really works if all drivers use this, so convert this UVC gadget driver. Signed-off-by: Hans Verkuil Reviewed-by: Laurent Pinchart Acked-by: Felipe Balbi Signed-off-by: Mauro Carvalho Chehab

usb: gadget: uvc: Remove uvc_set_trace_param() function

2018-09-25T15:48:07+00:00

The function is never called, remove it. Signed-off-by: Laurent Pinchart Reviewed-by: Kieran Bingham