Messages in this thread Patch in this message | | | Date | Fri, 19 Oct 2007 23:06:18 +0200 (CEST) | From | Jiri Kosina <> | Subject | Re: Locking problem in usbserial with 2.6.23-git 5a34417f |
| |
On Fri, 19 Oct 2007, Larry Finger wrote:
> While attempting to configure a new USB modem, the following locking > problem occurred. In addition, shortly after this problem occurred, the > computer froze. The log data starts at the point that usbserial was > loaded and contains everything that was written to disk before the > machine locked up. Some info may be missing from the end of the stack > dump.
I guess this one is needed.
From: Jiri Kosina <jkosina@suse.cz>
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>
diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c index 88a2c7d..6f8d712 100644 --- a/drivers/usb/serial/generic.c +++ b/drivers/usb/serial/generic.c @@ -208,14 +208,15 @@ int usb_serial_generic_write(struct usb_serial_port *port, const unsigned char * /* 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); 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; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |