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Thu, 2 Nov 2023 13:00:37 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1698926438; bh=ntl+rkppSxBHVspDsAeKPojZUHoGlZ8H2bX3BZ0P5ek=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=UAFAPWc5+xZN5TkwY8WyK0sMqeW262k2lF2wYUw2KMiaABhBufG0FSICPaZyX5gwx KpZt3QzefVb/ocC0yzAuSKqNIVFVcRrbGbnUzCINK99kuqhZjSTzDmUArFAhbfji7s He+YfYL4q7DaKiITxPxb9we0/g34AS0vWpVL1eOU= Message-ID: <80a05f4a-eaae-4db1-9604-c5eed9ff594c@ideasonboard.com> Date: Thu, 2 Nov 2023 12:00:52 +0000 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] usb: gadget: uvc_video: unlock before submitting a request to ep Content-Language: en-US To: Piyush Mehta , laurent.pinchart@ideasonboard.com, michal.simek@amd.com, gregkh@linuxfoundation.org Cc: siva.durga.prasad.paladugu@amd.com, radhey.shyam.pandey@amd.com, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org References: <20231102071138.828126-1-piyush.mehta@amd.com> From: Dan Scally Autocrypt: addr=dan.scally@ideasonboard.com; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Piyush - thanks for the patch On 02/11/2023 07:11, Piyush Mehta wrote: > There could be chances where the usb_ep_queue() could fail and trigger > complete() handler with error status. In this case, if usb_ep_queue() > is called with lock held and the triggered complete() handler is waiting > for the same lock to be cleared could result in a deadlock situation and > could result in system hang. To aviod this scenerio, call usb_ep_queue() > with lock removed. This patch does the same. s/aviod/avoid. s/scenerio/scenario/ > > Signed-off-by: Piyush Mehta > --- > drivers/usb/gadget/function/uvc_video.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/usb/gadget/function/uvc_video.c b/drivers/usb/gadget/function/uvc_video.c > index 91af3b1ef0d4..0a5d9ac145e7 100644 > --- a/drivers/usb/gadget/function/uvc_video.c > +++ b/drivers/usb/gadget/function/uvc_video.c > @@ -460,11 +460,12 @@ static void uvcg_video_pump(struct work_struct *work) > req->no_interrupt = 1; > } > > - /* Queue the USB request */ > - ret = uvcg_video_ep_queue(video, req); > spin_unlock_irqrestore(&queue->irqlock, flags); > > + /* Queue the USB request */ > + ret = uvcg_video_ep_queue(video, req); > if (ret < 0) { > + usb_ep_set_halt(video->ep); This change isn't mentioned, and shouldn't be necessary - uvcg_video_ep_queue() will already call usb_ep_set_halt() if it's in the error path. > uvcg_queue_cancel(queue, 0); > break; > }