From: Felipe Balbi <balbi@kernel.org>
To: Jerome Brunet <jbrunet@baylibre.com>
Cc: Ruslan Bilovol <ruslan.bilovol@gmail.com>,
Pavel Hofman <pavel.hofman@ivitera.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jack Pham <jackp@codeaurora.org>,
linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org,
Thinh Nguyen <Thinh.Nguyen@synopsys.com>,
Ferry Toth <ftoth@exalondelft.nl>
Subject: Re: [PATCH] usb: gadget: f_uac2: fixup feedback endpoint stop
Date: Fri, 27 Aug 2021 11:05:38 +0300 [thread overview]
Message-ID: <87a6l39us6.fsf@kernel.org> (raw)
In-Reply-To: <20210827075853.266912-1-jbrunet@baylibre.com>
Hi,
Jerome Brunet <jbrunet@baylibre.com> writes:
> When the uac2 function is stopped, there seems to be an issue reported on
> some platforms (Intel Merrifield at least)
>
> BUG: kernel NULL pointer dereference, address: 0000000000000008
> ...
> RIP: 0010:dwc3_gadget_del_and_unmap_request+0x19/0xe0
> ...
> Call Trace:
> dwc3_remove_requests.constprop.0+0x12f/0x170
> __dwc3_gadget_ep_disable+0x7a/0x160
> dwc3_gadget_ep_disable+0x3d/0xd0
> usb_ep_disable+0x1c/0x70
> u_audio_stop_capture+0x79/0x120 [u_audio]
> afunc_set_alt+0x73/0x80 [usb_f_uac2]
> composite_setup+0x224/0x1b90 [libcomposite]
>
> The issue happens only when the gadget is using the sync type "async", not
> "adaptive". This indicates that problem is coming from the feedback
> endpoint, which is only used with async synchronization mode.
>
> The problem is that request is freed regardless of usb_ep_dequeue(), which
> ends up badly if the request is not actually dequeued yet.
>
> Update the feedback endpoint free function to release the endpoint the same
> way it is done for the data endpoint, which takes care of the problem.
>
> Reported-by: Ferry Toth <ftoth@exalondelft.nl>
> Tested-by: Ferry Toth <ftoth@exalondelft.nl>
> Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
> ---
> Hi Felipe,
>
> This solves the issue reported here [0] and makes revert [1]
> unnecessary.
awesome work! Thanks
Acked-by: Felipe Balbi <balbi@kernel.org>
--
balbi
next prev parent reply other threads:[~2021-08-27 8:06 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-27 7:58 [PATCH] usb: gadget: f_uac2: fixup feedback endpoint stop Jerome Brunet
2021-08-27 8:05 ` Felipe Balbi [this message]
2021-08-27 9:26 ` Jerome Brunet
-- strict thread matches above, loose matches on Subject: below --
2021-08-24 20:14 [PATCH v1 1/3] Revert "usb: gadget: u_audio: add real feedback implementation" Ferry Toth
2021-08-25 9:21 ` [PATCH] usb: gadget: f_uac2: fixup feedback endpoint stop Jerome Brunet
2021-08-25 20:07 ` Ferry Toth
2021-08-25 21:42 ` Thinh Nguyen
2021-08-26 7:25 ` Jerome Brunet
2021-08-27 0:50 ` Thinh Nguyen
2021-08-27 8:38 ` Jerome Brunet
2021-08-27 23:30 ` Thinh Nguyen
2021-08-26 7:23 ` Jerome Brunet
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