Patch "usb: renesas_usbhs: fix to avoid using a disabled ep in usbhsg_queue_done()" has been added to the 4.4-stable tree

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

usb: renesas_usbhs: fix to avoid using a disabled ep in usbhsg_queue_done()

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
usb-renesas_usbhs-fix-to-avoid-using-a-disabled-ep-in-usbhsg_queue_done.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Yoshihiro Shimoda <[email protected]>
Date: Mon, 4 Apr 2016 20:40:20 +0900
Subject: usb: renesas_usbhs: fix to avoid using a disabled ep in usbhsg_queue_done()

From: Yoshihiro Shimoda <[email protected]>

commit 4fccb0767fdbdb781a9c5b5c15ee7b219443c89d upstream.

This patch fixes an issue that usbhsg_queue_done() may cause kernel panic when dma callback is running and usb_ep_disable() is called by interrupt handler. (Especially, we can reproduce this issue using g_audio with usb-dmac driver.)

For example of a flow:
usbhsf_dma_complete (on tasklet)
--> usbhsf_pkt_handler (on tasklet)
--> usbhsg_queue_done (on tasklet)
*** interrupt happened and usb_ep_disable() is called *** --> usbhsg_queue_pop (on tasklet)
Then, oops happened.

---
 drivers/usb/renesas_usbhs/mod_gadget.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

@@ -158,10 +158,14 @@ static void usbhsg_queue_done(struct usb
 	struct usbhs_pipe *pipe = pkt->pipe;
 	struct usbhsg_uep *uep = usbhsg_pipe_to_uep(pipe);
 	struct usbhsg_request *ureq = usbhsg_pkt_to_ureq(pkt);
+	unsigned long flags;
 
 	ureq->req.actual = pkt->actual;
 
-	usbhsg_queue_pop(uep, ureq, 0);
+	usbhs_lock(priv, flags);
+	if (uep)
+		__usbhsg_queue_pop(uep, ureq, 0);
+	usbhs_unlock(priv, flags);
 }
 
 static void usbhsg_queue_push(struct usbhsg_uep *uep,

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/usb-renesas_usbhs-fix-to-avoid-using-a-disabled-ep-in-usbhsg_queue_done.patch queue-4.4/usb-renesas_usbhs-avoid-null-pointer-derefernce-in-usbhsf_pkt_handler.patch queue-4.4/usb-renesas_usbhs-disable-tx-irq-before-starting-tx-dmac-transfer.patch