| From acd2a847e7fee7df11817f67dba75a2802793e5d Mon Sep 17 00:00:00 2001 |
| From: Jiri Kosina <jkosina@suse.cz> |
| Date: Sat, 20 Oct 2007 00:05:19 +0200 |
| Subject: USB: usbserial - fix potential deadlock between write() and IRQ |
| Message-ID: <20071102152622.GB7279@kroah.com> |
| |
| From: Jiri Kosina <jkosina@suse.cz> |
| |
| patch acd2a847e7fee7df11817f67dba75a2802793e5d in mainline. |
| |
| USB: usbserial - fix potential deadlock between write() and IRQ |
| |
| usb_serial_generic_write() doesn't disable interrupts when taking port->lock, |
| and could therefore deadlock with usb_serial_generic_read_bulk_callback() |
| being called from interrupt, taking the same lock. Fix it. |
| |
| Signed-off-by: Jiri Kosina <jkosina@suse.cz> |
| Acked-by: Larry Finger <larry.finger@lwfinger.net> |
| Cc: Marcin Slusarz <marcin.slusarz@gmail.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> |
| |
| --- |
| drivers/usb/serial/generic.c | 7 ++++--- |
| 1 file changed, 4 insertions(+), 3 deletions(-) |
| |
| --- a/drivers/usb/serial/generic.c |
| +++ b/drivers/usb/serial/generic.c |
| @@ -190,14 +190,15 @@ int usb_serial_generic_write(struct usb_ |
| |
| /* only do something if we have a bulk out endpoint */ |
| if (serial->num_bulk_out) { |
| - spin_lock_bh(&port->lock); |
| + unsigned long flags; |
| + spin_lock_irqsave(&port->lock, flags); |
| if (port->write_urb_busy) { |
| - spin_unlock_bh(&port->lock); |
| + spin_unlock_irqrestore(&port->lock, flags); |
| dbg("%s - already writing", __FUNCTION__); |
| return 0; |
| } |
| port->write_urb_busy = 1; |
| - spin_unlock_bh(&port->lock); |
| + spin_unlock_irqrestore(&port->lock, flags); |
| |
| count = (count > port->bulk_out_size) ? port->bulk_out_size : count; |
| |