Re: [Bug 8473] New: Oops: 0010 [1] SMP

[Paul Fulghum <paulkf@microgate.com>]

On Fri, 2007-06-08 at 05:06 +0200, Björn Steinbrink wrote:
> This is do_tty_hangup() exchanging the fops while we're waiting for the
> lock. The new fops (hung_up_tty_fops) only have the unlocked variant and
> thus we Oops our way.
> 
> The following program reproduces it quite easily on a SMP box. I'm
> running it from X as root like this:
> while true; do xterm /path/to/program; done

I am unable to reproduce the oops on either i386 SMP or x86_64 SMP
using your test program. This is against plain 2.6.21 with only
my compat ioctl patch applied.

Here is a patch that restores the locked ioctl for hung_up_tty_ioctl.
Can you try it and see if it removes your oops?

--- a/drivers/char/tty_io.c	2007-06-08 10:07:39.000000000 -0500
+++ b/drivers/char/tty_io.c	2007-06-08 10:09:59.000000000 -0500
@@ -1150,8 +1150,14 @@ static unsigned int hung_up_tty_poll(str
 	return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
 }
 
-static long hung_up_tty_ioctl(struct file * file,
-			      unsigned int cmd, unsigned long arg)
+static int hung_up_tty_ioctl(struct inode * inode, struct file * file,
+			     unsigned int cmd, unsigned long arg)
+{
+	return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
+}
+
+static long hung_up_tty_compat_ioctl(struct file * file,
+				     unsigned int cmd, unsigned long arg)
 {
 	return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
 }
@@ -1199,8 +1205,8 @@ static const struct file_operations hung
 	.read		= hung_up_tty_read,
 	.write		= hung_up_tty_write,
 	.poll		= hung_up_tty_poll,
-	.unlocked_ioctl = hung_up_tty_ioctl,
-	.compat_ioctl	= hung_up_tty_ioctl,
+	.ioctl		= hung_up_tty_ioctl,
+	.compat_ioctl	= hung_up_tty_compat_ioctl,
 	.release	= tty_release,
 };