From 1dc3bab3aa1f9a09c7da1a9fcde37255c3194ce5 Mon Sep 17 00:00:00 2001
From: Brad Stein <Brad.Stein@gmail.com>
Date: Tue, 27 Jan 2026 01:13:09 -0300
Subject: [PATCH] kernel: guard missing uvc ep desc

---
 scripts/kernel/uvc-debug.patch | 27 +++++++++++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)

diff --git a/scripts/kernel/uvc-debug.patch b/scripts/kernel/uvc-debug.patch
index b73e678..21caae2 100644
--- a/scripts/kernel/uvc-debug.patch
+++ b/scripts/kernel/uvc-debug.patch
@@ -52,7 +52,7 @@
  	for (i = 0; i < video->uvc_num_requests; i++) {
  		ureq = kzalloc(sizeof(struct uvc_request), GFP_KERNEL);
  		if (ureq == NULL)
-@@ -764,20 +792,70 @@
+@@ -764,20 +792,78 @@
  {
  	int ret;
  
@@ -74,6 +74,14 @@
  		return -ENODEV;
  	}
  
++	if (!video->ep->desc) {
++		uvcg_err(&video->uvc->func,
++			"Video enable failed, missing ep desc ep=%p maxpacket=%u maxburst=%u mult=%u\n",
++			video->ep, video->ep->maxpacket,
++			video->ep->maxburst, video->ep->mult);
++		return -EINVAL;
++	}
++
 +	if (!video->kworker || !video->async_wq) {
 +		uvcg_err(&video->uvc->func,
 +			"Video enable failed, missing worker(s) kworker=%p async_wq=%p\n",
@@ -125,7 +133,22 @@
  
 --- a/drivers/usb/gadget/function/f_uvc.c
 +++ b/drivers/usb/gadget/function/f_uvc.c
-@@ -362,10 +362,34 @@
+@@ -298,6 +298,14 @@
+ 	int ret;
+ 
+ 	uvcg_info(f, "%s(%u, %u)\n", __func__, interface, alt);
++	uvcg_info(f,
++		"UVC set_alt: intf=%u alt=%u state=%u speed=%u ep=%p desc=%p maxpacket=%u maxburst=%u mult=%u\n",
++		interface, alt, uvc->state, cdev->gadget->speed,
++		uvc->video.ep,
++		uvc->video.ep ? uvc->video.ep->desc : NULL,
++		uvc->video.ep ? uvc->video.ep->maxpacket : 0,
++		uvc->video.ep ? uvc->video.ep->maxburst : 0,
++		uvc->video.ep ? uvc->video.ep->mult : 0);
+ 
+ 	if (interface == uvc->control_intf) {
+ 		if (alt)
+@@ -362,10 +370,34 @@
  			return ret;
  		usb_ep_enable(uvc->video.ep);