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

Paul Fulghum
2007-06-08T15:18:20Z

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,
};