Hi,
With reference to these two bugs:
http://bugzilla.kernel.org/show_bug.cgi?id=5958
http://bugzilla.kernel.org/show_bug.cgi?id=6131
it seems that folk are under the impression that serial_core is
responsible for these bugs. It isn't.
Calling serial functions to flush buffers, or try to send more data
after the port has been closed or hung up is a bug in the code doing
the calling, not in the serial_core driver.
Make this explicitly obvious by adding BUG_ON()'s.
I don't particularly want to add these BUG_ON()'s since they have a
performance impact, but it seems that they're necessary to convey
sufficient understanding about where the bug lies. The Bluetooth
problem has been around for _ages_ (longer than the entry in bugzilla)
and no one seems the least bit interested in fixing the fscking thing.
I can only hope that adding these BUG_ON()'s provides sufficient
clarity to cause people to look elsewhere.
diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
--- a/drivers/serial/serial_core.c
+++ b/drivers/serial/serial_core.c
@@ -71,6 +71,11 @@ static void uart_change_pm(struct uart_s
void uart_write_wakeup(struct uart_port *port)
{
struct uart_info *info = port->info;
+ /*
+ * This means you called this function _after_ the port was
+ * closed. No cookie for you.
+ */
+ BUG_ON(!info);
tasklet_schedule(&info->tlet);
}
@@ -479,6 +484,12 @@ uart_write(struct tty_struct *tty, const
unsigned long flags;
int c, ret = 0;
+ /*
+ * This means you called this function _after_ the port was
+ * closed. No cookie for you.
+ */
+ BUG_ON(!state);
+
if (!circ->buf)
return 0;
@@ -521,6 +532,12 @@ static void uart_flush_buffer(struct tty
struct uart_port *port = state->port;
unsigned long flags;
+ /*
+ * This means you called this function _after_ the port was
+ * closed. No cookie for you.
+ */
+ BUG_ON(!state);
+
DPRINTK("uart_flush_buffer(%d) called\n", tty->index);
spin_lock_irqsave(&port->lock, flags);
--
Russell King
Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/
maintainer of: 2.6 Serial core
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