[PATCH v7] usb: gadget: uvc: Fix null pointer dereference in uvcg_video_init()

In uvcg_video_init(), if kthread_run_worker() fails,
the error logged uses uvcg_err(), however, the pointer it uses:
video->uvc is not assigned at this point, triggering a null
pointer dereference. Fix this by directly using uvc->func which
is assigned already.

Reported-by: [email protected]
Closes: https://syzkaller.appspot.com/bug?extid=8dcac923582c28505fd7
Fixes: f0bbfbd16b3b ("usb: gadget: uvc: rework to enqueue in pump worker from encoded queue")
Cc: [email protected]
Signed-off-by: Jeffin Philip <[email protected]>
---
Changes in v7:
Changed Fixes: tag hash mentioned incorrectly to be updated before in v4
 
Changes in v6:
No code changes from v5
 
Changes in v5:
Added changelog as per maintainer suggestions
 
Changes in v4:
Changed Fixes commit line as per Xu Yang's suggestion
 
Changes in v3:
Shortened SHA1 hash as per maintainer comment
 
Changes in v2:
 -Changed subject of the patch to include subsystem as per Xu Yang's comment
 -Changed incorrect "Fixes" tag to "Closes"
 -Rewrote the patch to use uvc->func rather than declaring video->uvc first
  as per Xu Yang's comment
---
 drivers/usb/gadget/function/uvc_video.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/gadget/function/uvc_video.c b/drivers/usb/gadget/function/uvc_video.c
index 2f9700b3f1b6..9ba09118bb74 100644
--- a/drivers/usb/gadget/function/uvc_video.c
+++ b/drivers/usb/gadget/function/uvc_video.c
@@ -821,7 +821,7 @@ int uvcg_video_init(struct uvc_video *video, struct uvc_device *uvc)
 	/* Allocate a kthread for asynchronous hw submit handler. */
 	video->kworker = kthread_run_worker(0, "UVCG");
 	if (IS_ERR(video->kworker)) {
-		uvcg_err(&video->uvc->func, "failed to create UVCG kworker\n");
+		uvcg_err(&uvc->func, "failed to create UVCG kworker\n");
 		return PTR_ERR(video->kworker);
 	}
 
-- 
2.55.0