This is a note to let you know that I've just added the patch titled

usb: gadget: u_audio: fix race condition on endpoint stop

to my usb git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git in the usb-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From 068fdad20454f815e61e6f6eb9f051a8b3120e88 Mon Sep 17 00:00:00 2001

From: Jerome Brunet jbrunet@baylibre.com Date: Fri, 27 Aug 2021 11:29:27 +0200 Subject: usb: gadget: u_audio: fix race condition on endpoint stop

If the endpoint completion callback is call right after the ep_enabled flag is cleared and before usb_ep_dequeue() is call, we could do a double free on the request and the associated buffer.

Fix this by clearing ep_enabled after all the endpoint requests have been dequeued.

Fixes: 7de8681be2cd ("usb: gadget: u_audio: Free requests only after callback") Cc: stable stable@vger.kernel.org Reported-by: Thinh Nguyen Thinh.Nguyen@synopsys.com Signed-off-by: Jerome Brunet jbrunet@baylibre.com Link: https://lore.kernel.org/r/20210827092927.366482-1-jbrunet@baylibre.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/usb/gadget/function/u_audio.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/gadget/function/u_audio.c b/drivers/usb/gadget/function/u_audio.c index 63d9340f008e..9e5c950612d0 100644 --- a/drivers/usb/gadget/function/u_audio.c +++ b/drivers/usb/gadget/function/u_audio.c @@ -394,8 +394,6 @@ static inline void free_ep(struct uac_rtd_params *prm, struct usb_ep *ep) if (!prm->ep_enabled) return;

- prm->ep_enabled = false; - audio_dev = uac->audio_dev; params = &audio_dev->params;

@@ -413,6 +411,8 @@ static inline void free_ep(struct uac_rtd_params *prm, struct usb_ep *ep) } }

+ prm->ep_enabled = false; + if (usb_ep_disable(ep)) dev_err(uac->card->dev, "%s:%d Error!\n", __func__, __LINE__); } @@ -424,8 +424,6 @@ static inline void free_ep_fback(struct uac_rtd_params *prm, struct usb_ep *ep) if (!prm->fb_ep_enabled) return;

- prm->fb_ep_enabled = false; - if (prm->req_fback) { if (usb_ep_dequeue(ep, prm->req_fback)) { kfree(prm->req_fback->buf); @@ -434,6 +432,8 @@ static inline void free_ep_fback(struct uac_rtd_params *prm, struct usb_ep *ep) prm->req_fback = NULL; }

+ prm->fb_ep_enabled = false; + if (usb_ep_disable(ep)) dev_err(uac->card->dev, "%s:%d Error!\n", __func__, __LINE__); }