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USB: usbserial - fix potential deadlock between write() and IRQ

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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>
This commit is contained in:
Jiri Kosina 2007-10-20 00:05:19 +02:00 committed by Greg Kroah-Hartman
parent 8a28dea3ac
commit acd2a847e7
1 changed files with 4 additions and 3 deletions
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7
drivers/usb/serial/generic.c
View file

@ -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);
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;