uml: DEBUG_SHIRQ fixes

A couple more DEBUG_SHIRQ fixes.

The previous mconsole blocking fix exposed the lack of O_NONBLOCK on the
mconsole socket.

Also, winch_interrupt started crashing because it is called at irq free time
and it tries to dereference tty->driver_data, which has already been set to
NULL.

I added some error cleanup in mconsole_init while I was there.

Cc: "Karol Swietlicki" <magotari@gmail.com>
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/um/drivers/line.c

@@ -774,10 +774,12 @@ static irqreturn_t winch_interrupt(int irq, void *data)
 	tty = winch->tty;
 	if (tty != NULL) {
 		line = tty->driver_data;
+		if (line != NULL) {
 			chan_window_size(&line->chan_list, &tty->winsize.ws_row,
 					 &tty->winsize.ws_col);
 			kill_pgrp(tty->pgrp, SIGWINCH, 1);
 		}
+	}
  out:
 	if (winch->fd != -1)
 		reactivate_fd(winch->fd, WINCH_IRQ);

arch/um/drivers/mconsole_kern.c

@@ -792,6 +792,8 @@ static int __init mconsole_init(void)
 		printk(KERN_ERR "Failed to initialize management console\n");
 		return 1;
 	}
+	if (os_set_fd_block(sock, 0))
+		goto out;
 
 	register_reboot_notifier(&reboot_notifier);
 
@@ -800,7 +802,7 @@ static int __init mconsole_init(void)
 			     "mconsole", (void *)sock);
 	if (err) {
 		printk(KERN_ERR "Failed to get IRQ for management console\n");
-		return 1;
+		goto out;
 	}
 
 	if (notify_socket != NULL) {
@@ -816,6 +818,10 @@ static int __init mconsole_init(void)
 	printk(KERN_INFO "mconsole (version %d) initialized on %s\n",
 	       MCONSOLE_VERSION, mconsole_socket_name);
 	return 0;
+
+ out:
+	os_close_file(sock);
+	return 1;
 }
 
 __initcall(mconsole_init);