Commit 38ad2ed0 authored Jun 16, 2007 by Paul Fulghum Committed by Linus Torvalds Jun 16, 2007

tty: restore locked ioctl file op



Restore tty locked ioctl handler which was replaced with
an unlocked ioctl handler in hung_up_tty_fops by the patch:

commit e10cc1df
Author: Paul Fulghum <paulkf@microgate.com>
Date:   Thu May 10 22:22:50 2007 -0700

    tty: add compat_ioctl

This was reported in:
[Bug 8473] New: Oops: 0010 [1] SMP

The bug is caused by switching to hung_up_tty_fops in do_tty_hangup.  An
ioctl call can be waiting on BLK after testing for existence of the locked
ioctl handler in the normal tty fops, but before calling the locked ioctl
handler.  If a hangup occurs at that point, the locked ioctl fop is NULL
and an oops occurs.

(akpm: we can remove my debugging code from do_ioctl() now, but it'll be OK to
do that for 2.6.23)

Signed-off-by: Paul Fulghum <paulkf@microgate.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent f4d27817

drivers/char/tty_io.c

+10 −4

Original line number	Diff line number	Diff line
		@@ -1173,7 +1173,13 @@ static unsigned int hung_up_tty_poll(struct file * filp, poll_table * wait)
		return POLLIN \| POLLOUT \| POLLERR \| POLLHUP \| POLLRDNORM \| POLLWRNORM;
		}

		static long hung_up_tty_ioctl(struct file * file,
		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;
		@@ -1222,8 +1228,8 @@ static const struct file_operations hung_up_tty_fops = {
		.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,
		};

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