This is a note to let you know that I've just added the patch titled
usb: gadget: function: printer: avoid wrong list handling in
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-testing 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 be merged to the usb-next branch sometime soon,
after it passes testing, and the merge window is open.
If you have any questions about this process, please let me know.
>From 4a014a7339f441b0851ce012f469c0fadac61c81 Mon Sep 17 00:00:00 2001
From: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
Date: Mon, 21 May 2018 20:18:07 +0900
Subject: usb: gadget: function: printer: avoid wrong list handling in
printer_write()
When printer_write() calls usb_ep_queue(), a udc driver (e.g.
renesas_usbhs driver) may call usb_gadget_giveback_request() in
the udc .queue ops immediately. Then, printer_write() calls
list_add(&req->list, &dev->tx_reqs_active) wrongly. After that,
if we do unbind the printer driver, WARN_ON() happens in
printer_func_unbind() because the list entry is not removed.
So, this patch moves list_add(&req->list, &dev->tx_reqs_active)
calling before usb_ep_queue().
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
Acked-by: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/gadget/function/f_printer.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/usb/gadget/function/f_printer.c b/drivers/usb/gadget/function/f_printer.c
index d359efe06c76..9c7ed2539ff7 100644
--- a/drivers/usb/gadget/function/f_printer.c
+++ b/drivers/usb/gadget/function/f_printer.c
@@ -631,19 +631,19 @@ printer_write(struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
return -EAGAIN;
}
+ list_add(&req->list, &dev->tx_reqs_active);
+
/* here, we unlock, and only unlock, to avoid deadlock. */
spin_unlock(&dev->lock);
value = usb_ep_queue(dev->in_ep, req, GFP_ATOMIC);
spin_lock(&dev->lock);
if (value) {
+ list_del(&req->list);
list_add(&req->list, &dev->tx_reqs);
spin_unlock_irqrestore(&dev->lock, flags);
mutex_unlock(&dev->lock_printer_io);
return -EAGAIN;
}
-
- list_add(&req->list, &dev->tx_reqs_active);
-
}
spin_unlock_irqrestore(&dev->lock, flags);
--
2.17.0
