diff options
| author | Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> | 2018-05-21 20:18:07 +0900 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-05-24 18:14:28 +0200 |
| commit | 4a014a7339f441b0851ce012f469c0fadac61c81 (patch) | |
| tree | f3837cf543a746965033a29c245f15e6fea6f133 /drivers/usb | |
| parent | c97a8cc17f4472d85f889230ea6bac5aa8c53560 (diff) | |
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@renesas.com>
Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb')
| -rw-r--r-- | drivers/usb/gadget/function/f_printer.c | 6 |
1 files 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); |