USB: usbserial - fix potential deadlock between write() and IRQ
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c
index 88a2c7d..9eb4a65 100644
--- a/drivers/usb/serial/generic.c
+++ b/drivers/usb/serial/generic.c
@@ -208,14 +208,15 @@
/* 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;