usb: gadget: uvc: Remove nested locking
authorAvichal Rakesh <arakesh@google.com>
Thu, 4 Jan 2024 21:50:09 +0000 (13:50 -0800)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Fri, 5 Jan 2024 09:35:57 +0000 (10:35 +0100)
commit9866dc4314c6c858e451933f965d64532aec00a9
tree96aeb09937340fe72fc765dc635f43498e9f63c8
parentfe814b5b0f3042f1a583734497e726ee53783cc1
usb: gadget: uvc: Remove nested locking

When handling error status from uvcg_video_usb_req_queue,
uvc_video_complete currently calls uvcg_queue_cancel with
video->req_lock held. uvcg_queue_cancel internally locks
queue->irqlock, which nests queue->irqlock inside
video->req_lock. This isn't a functional bug at the
moment, but does open up possibilities for ABBA
deadlocks in the future.

This patch fixes the accidental nesting by dropping
video->req_lock before calling uvcg_queue_cancel.

Fixes: 6acba0345b68 ("usb:gadget:uvc Do not use worker thread to pump isoc usb requests")
Signed-off-by: Avichal Rakesh <arakesh@google.com>
Link: https://lore.kernel.org/r/20240104215009.2252452-2-arakesh@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/usb/gadget/function/uvc_video.c