tty: revert incorrectly applied lock patch
I sent GregKH this after the pre-requisites. He dropped the pre-requesites
for good reason and unfortunately then applied this patch. Without this
reverted you get random kernel memory corruption which will make bisecting
anything between it and the properly applied patches a complete sod.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index ca7c25d..ac96f74 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -185,7 +185,6 @@
put_device(tty->dev);
kfree(tty->write_buf);
tty_buffer_free_all(tty);
- tty->magic = 0xDEADDEAD;
kfree(tty);
}
@@ -574,7 +573,7 @@
}
spin_unlock(&redirect_lock);
- tty_lock(tty);
+ tty_lock();
/* some functions below drop BTM, so we need this bit */
set_bit(TTY_HUPPING, &tty->flags);
@@ -667,7 +666,7 @@
clear_bit(TTY_HUPPING, &tty->flags);
tty_ldisc_enable(tty);
- tty_unlock(tty);
+ tty_unlock();
if (f)
fput(f);
@@ -1104,12 +1103,12 @@
{
if (tty) {
mutex_lock(&tty->atomic_write_lock);
- tty_lock(tty);
+ tty_lock();
if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags)) {
- tty_unlock(tty);
+ tty_unlock();
tty->ops->write(tty, msg, strlen(msg));
} else
- tty_unlock(tty);
+ tty_unlock();
tty_write_unlock(tty);
}
return;
@@ -1404,7 +1403,6 @@
}
initialize_tty_struct(tty, driver, idx);
- tty_lock(tty);
retval = tty_driver_install_tty(driver, tty);
if (retval < 0)
goto err_deinit_tty;
@@ -1420,11 +1418,9 @@
retval = tty_ldisc_setup(tty, tty->link);
if (retval)
goto err_release_tty;
- /* Return the tty locked so that it cannot vanish under the caller */
return tty;
err_deinit_tty:
- tty_unlock(tty);
deinitialize_tty_struct(tty);
free_tty_struct(tty);
err_module_put:
@@ -1433,7 +1429,6 @@
/* call the tty release_tty routine to clean out this slot */
err_release_tty:
- tty_unlock(tty);
printk_ratelimited(KERN_INFO "tty_init_dev: ldisc open failed, "
"clearing slot %d\n", idx);
release_tty(tty, idx);
@@ -1636,7 +1631,7 @@
if (tty_paranoia_check(tty, inode, __func__))
return 0;
- tty_lock(tty);
+ tty_lock();
check_tty_count(tty, __func__);
__tty_fasync(-1, filp, 0);
@@ -1645,11 +1640,10 @@
pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
tty->driver->subtype == PTY_TYPE_MASTER);
devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0;
- /* Review: parallel close */
o_tty = tty->link;
if (tty_release_checks(tty, o_tty, idx)) {
- tty_unlock(tty);
+ tty_unlock();
return 0;
}
@@ -1661,7 +1655,7 @@
if (tty->ops->close)
tty->ops->close(tty, filp);
- tty_unlock(tty);
+ tty_unlock();
/*
* Sanity check: if tty->count is going to zero, there shouldn't be
* any waiters on tty->read_wait or tty->write_wait. We test the
@@ -1684,7 +1678,7 @@
opens on /dev/tty */
mutex_lock(&tty_mutex);
- tty_lock_pair(tty, o_tty);
+ tty_lock();
tty_closing = tty->count <= 1;
o_tty_closing = o_tty &&
(o_tty->count <= (pty_master ? 1 : 0));
@@ -1715,7 +1709,7 @@
printk(KERN_WARNING "%s: %s: read/write wait queue active!\n",
__func__, tty_name(tty, buf));
- tty_unlock_pair(tty, o_tty);
+ tty_unlock();
mutex_unlock(&tty_mutex);
schedule();
}
@@ -1778,7 +1772,7 @@
/* check whether both sides are closing ... */
if (!tty_closing || (o_tty && !o_tty_closing)) {
- tty_unlock_pair(tty, o_tty);
+ tty_unlock();
return 0;
}
@@ -1791,16 +1785,14 @@
tty_ldisc_release(tty, o_tty);
/*
* The release_tty function takes care of the details of clearing
- * the slots and preserving the termios structure. The tty_unlock_pair
- * should be safe as we keep a kref while the tty is locked (so the
- * unlock never unlocks a freed tty).
+ * the slots and preserving the termios structure.
*/
release_tty(tty, idx);
- tty_unlock_pair(tty, o_tty);
/* Make this pty number available for reallocation */
if (devpts)
devpts_kill_index(inode, idx);
+ tty_unlock();
return 0;
}
@@ -1904,9 +1896,6 @@
* Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
* tty->count should protect the rest.
* ->siglock protects ->signal/->sighand
- *
- * Note: the tty_unlock/lock cases without a ref are only safe due to
- * tty_mutex
*/
static int tty_open(struct inode *inode, struct file *filp)
@@ -1930,7 +1919,8 @@
retval = 0;
mutex_lock(&tty_mutex);
- /* This is protected by the tty_mutex */
+ tty_lock();
+
tty = tty_open_current_tty(device, filp);
if (IS_ERR(tty)) {
retval = PTR_ERR(tty);
@@ -1951,19 +1941,17 @@
}
if (tty) {
- tty_lock(tty);
retval = tty_reopen(tty);
- if (retval < 0) {
- tty_unlock(tty);
+ if (retval)
tty = ERR_PTR(retval);
- }
- } else /* Returns with the tty_lock held for now */
+ } else
tty = tty_init_dev(driver, index);
mutex_unlock(&tty_mutex);
if (driver)
tty_driver_kref_put(driver);
if (IS_ERR(tty)) {
+ tty_unlock();
retval = PTR_ERR(tty);
goto err_file;
}
@@ -1992,7 +1980,7 @@
printk(KERN_DEBUG "%s: error %d in opening %s...\n", __func__,
retval, tty->name);
#endif
- tty_unlock(tty); /* need to call tty_release without BTM */
+ tty_unlock(); /* need to call tty_release without BTM */
tty_release(inode, filp);
if (retval != -ERESTARTSYS)
return retval;
@@ -2004,15 +1992,17 @@
/*
* Need to reset f_op in case a hangup happened.
*/
+ tty_lock();
if (filp->f_op == &hung_up_tty_fops)
filp->f_op = &tty_fops;
+ tty_unlock();
goto retry_open;
}
- tty_unlock(tty);
+ tty_unlock();
mutex_lock(&tty_mutex);
- tty_lock(tty);
+ tty_lock();
spin_lock_irq(¤t->sighand->siglock);
if (!noctty &&
current->signal->leader &&
@@ -2020,10 +2010,11 @@
tty->session == NULL)
__proc_set_tty(current, tty);
spin_unlock_irq(¤t->sighand->siglock);
- tty_unlock(tty);
+ tty_unlock();
mutex_unlock(&tty_mutex);
return 0;
err_unlock:
+ tty_unlock();
mutex_unlock(&tty_mutex);
/* after locks to avoid deadlock */
if (!IS_ERR_OR_NULL(driver))
@@ -2106,13 +2097,10 @@
static int tty_fasync(int fd, struct file *filp, int on)
{
- struct tty_struct *tty = file_tty(filp);
int retval;
-
- tty_lock(tty);
+ tty_lock();
retval = __tty_fasync(fd, filp, on);
- tty_unlock(tty);
-
+ tty_unlock();
return retval;
}
@@ -2949,7 +2937,6 @@
tty->pgrp = NULL;
tty->overrun_time = jiffies;
tty_buffer_init(tty);
- mutex_init(&tty->legacy_mutex);
mutex_init(&tty->termios_mutex);
mutex_init(&tty->ldisc_mutex);
init_waitqueue_head(&tty->write_wait);