From: Dmitry Torokhov Date: Tue, 16 Jun 2026 05:12:29 +0000 (-0700) Subject: Input: sur40 - fix input device registration ordering X-Git-Tag: v7.2~12^2~1 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9da976eb649c9e2f588a4499410e4d8af687925f;p=thirdparty%2Fkernel%2Flinux.git Input: sur40 - fix input device registration ordering In sur40_probe(), input_register_device() was previously called early before the V4L2 video device and vb2_queue components were fully initialized. If userspace opened the input device immediately upon registration, sur40_open() would trigger and start the sur40_poll() worker thread. This worker thread invokes sur40_process_video() and accesses the uninitialized vb2_queue structure, leading to a data race and potential system crash. Furthermore, if V4L2 or video registration failed after input_register_device() succeeded, the error path fell through to calling input_free_device() on a successfully registered device instead of input_unregister_device(), corrupting input core state. Move input_register_device() to the very end of sur40_probe(). This ensures the V4L2 and video queue structures are fully initialized before polling can start, and naturally resolves the error path bug since input_free_device() is now only called when input registration has not yet occurred. To maintain strict LIFO (Last-In, First-Out) teardown ordering, also move input_unregister_device() to the very beginning of sur40_disconnect(). This guarantees that the input polling worker thread is stopped before V4L2 video components or control handlers are unregistered. Reported-by: sashiko-bot@kernel.org Cc: stable@vger.kernel.org Assisted-by: Antigravity:gemini-3.5-flash Link: https://patch.msgid.link/20260616051235.1549517-1-dmitry.torokhov@gmail.com Signed-off-by: Dmitry Torokhov --- diff --git a/drivers/input/touchscreen/sur40.c b/drivers/input/touchscreen/sur40.c index fe63d53d56db..8639ec3ad703 100644 --- a/drivers/input/touchscreen/sur40.c +++ b/drivers/input/touchscreen/sur40.c @@ -725,21 +725,13 @@ static int sur40_probe(struct usb_interface *interface, goto err_free_input; } - /* register the polled input device */ - error = input_register_device(input); - if (error) { - dev_err(&interface->dev, - "Unable to register polled input device."); - goto err_free_buffer; - } - /* register the video master device */ snprintf(sur40->v4l2.name, sizeof(sur40->v4l2.name), "%s", DRIVER_LONG); error = v4l2_device_register(sur40->dev, &sur40->v4l2); if (error) { dev_err(&interface->dev, "Unable to register video master device."); - goto err_unreg_v4l2; + goto err_free_buffer; } /* initialize the lock and subdevice */ @@ -798,6 +790,14 @@ static int sur40_probe(struct usb_interface *interface, goto err_unreg_video; } + /* register the polled input device */ + error = input_register_device(input); + if (error) { + dev_err(&interface->dev, + "Unable to register polled input device."); + goto err_unreg_video; + } + /* we can register the device now, as it is ready */ usb_set_intfdata(interface, sur40); dev_dbg(&interface->dev, "%s is now attached\n", DRIVER_DESC); @@ -823,11 +823,12 @@ static void sur40_disconnect(struct usb_interface *interface) { struct sur40_state *sur40 = usb_get_intfdata(interface); + input_unregister_device(sur40->input); + v4l2_ctrl_handler_free(&sur40->hdl); video_unregister_device(&sur40->vdev); v4l2_device_unregister(&sur40->v4l2); - input_unregister_device(sur40->input); kfree(sur40->bulk_in_buffer); kfree(sur40);