if (!state->xmit.buf) {
state->xmit.buf = (unsigned char *) page;
uart_circ_clear(&state->xmit);
+ uart_port_unlock(uport, flags);
} else {
+ uart_port_unlock(uport, flags);
+ /*
+ * Do not free() the page under the port lock, see
+ * uart_shutdown().
+ */
free_page(page);
}
- uart_port_unlock(uport, flags);
retval = uport->ops->startup(uport);
if (retval == 0) {
struct uart_port *uport = uart_port_check(state);
struct tty_port *port = &state->port;
unsigned long flags = 0;
+ char *xmit_buf = NULL;
/*
* Set the TTY IO error marker
tty_port_set_suspended(port, 0);
/*
- * Free the transmit buffer page.
+ * Do not free() the transmit buffer page under the port lock since
+ * this can create various circular locking scenarios. For instance,
+ * console driver may need to allocate/free a debug object, which
+ * can endup in printk() recursion.
*/
uart_port_lock(state, flags);
- if (state->xmit.buf) {
- free_page((unsigned long)state->xmit.buf);
- state->xmit.buf = NULL;
- }
+ xmit_buf = state->xmit.buf;
+ state->xmit.buf = NULL;
uart_port_unlock(uport, flags);
+
+ if (xmit_buf)
+ free_page((unsigned long)xmit_buf);
}
/**