Hi,
as recently discussed on lkml the tty layer does call close() if
an open() fails. Usb-serial does not handle this correctly. It does
handle the first open() failing by checking the open count, but if
a second open() fails, the close() will free the resources associated
with the first open.
Regards
Oliver
Signed-off-by: Oliver Neukum <[EMAIL PROTECTED]>
--
--- a/drivers/usb/serial/usb-serial.c 2007-03-29 09:47:30.000000000 +0200
+++ b/drivers/usb/serial/usb-serial.c 2007-03-29 09:54:48.000000000 +0200
@@ -59,6 +59,7 @@
static int debug;
static struct usb_serial *serial_table[SERIAL_TTY_MINORS]; /* initially
all NULL */
+static unsigned long error_table[SERIAL_TTY_MINORS / BITS_PER_LONG];
static spinlock_t table_lock;
static LIST_HEAD(usb_serial_driver_list);
@@ -188,10 +189,12 @@
dbg("%s", __FUNCTION__);
- /* get the serial object associated with this tty pointer */
+ /* get the serial object associated with this tty pointer
+ * protected by BKL */
serial = usb_serial_get_by_index(tty->index);
if (!serial) {
tty->driver_data = NULL;
+ set_bit(tty->index, error_table);
return -ENODEV;
}
@@ -243,6 +246,7 @@
mutex_unlock(&port->mutex);
bailout_kref_put:
usb_serial_put(serial);
+ set_bit(tty->index, error_table);
return retval;
}
@@ -250,6 +254,15 @@
{
struct usb_serial_port *port = tty->driver_data;
+ /* this handles errors in open
+ * the tty layer will call close even if open fails
+ * we need to ignore such calls to close.
+ * All this happens under BKL - we must not sleep
+ * before checking for such calls to close
+ */
+ if (test_and_clear_bit(tty->index, error_table))
+ return;
+
if (!port)
return;
@@ -257,10 +270,7 @@
mutex_lock(&port->mutex);
- if (port->open_count == 0) {
- mutex_unlock(&port->mutex);
- return;
- }
+ WARN_ON(port->open_count == 0);
--port->open_count;
if (port->open_count == 0) {
@@ -1103,6 +1113,8 @@
serial_table[i] = NULL;
}
+ memset(error_table, 0x0, sizeof(error_table));
+
result = bus_register(&usb_serial_bus_type);
if (result) {
err("%s - registering bus driver failed", __FUNCTION__);
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