A panic can occur if the endpoint becomes disabled and the uvcg_video_pump adds the request back to the req_free list after it has already been queued to the endpoint. The endpoint complete will add the request back to the req_free list. Invalidate the local request handle once it's been queued.
<6>[ 246.796704][T13726] configfs-gadget gadget: uvc: uvc_function_set_alt(1, 0) <3>[ 246.797078][ T26] list_add double add: new=ffffff878bee5c40, prev=ffffff878bee5c40, next=ffffff878b0f0a90. <6>[ 246.797213][ T26] ------------[ cut here ]------------ <2>[ 246.797224][ T26] kernel BUG at lib/list_debug.c:31! <6>[ 246.807073][ T26] Call trace: <6>[ 246.807180][ T26] uvcg_video_pump+0x364/0x38c <6>[ 246.807366][ T26] process_one_work+0x2a4/0x544 <6>[ 246.807394][ T26] worker_thread+0x350/0x784 <6>[ 246.807442][ T26] kthread+0x2ac/0x320
Fixes: f9897ec0f6d3 ("usb: gadget: uvc: only pump video data if necessary") Cc: stable@vger.kernel.org Signed-off-by: Dan Vacura w36195@motorola.com --- drivers/usb/gadget/function/uvc_video.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/usb/gadget/function/uvc_video.c b/drivers/usb/gadget/function/uvc_video.c index 93f42c7f800d..59e2f51b53a5 100644 --- a/drivers/usb/gadget/function/uvc_video.c +++ b/drivers/usb/gadget/function/uvc_video.c @@ -427,6 +427,9 @@ static void uvcg_video_pump(struct work_struct *work) if (ret < 0) { uvcg_queue_cancel(queue, 0); break; + } else { + /* Endpoint now owns the request */ + req = NULL; } video->req_int_count++; }