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 <[EMAIL PROTECTED]>
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 <[EMAIL PROTECTED]>
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;
-
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