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Revert "tty: pty: Fix race condition between release_one_tty and pty_write" 

This reverts commit b9ca5f8560 as 0-day
shows it has a circular locking dependency.

Fixes: b9ca5f8560 ("tty: pty: Fix race condition between release_one_tty and pty_write")
Reported-by: kernel test robot <lkp@intel.com>
Cc: Sahara <keun-o.park@darkmatter.ae>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Greg Kroah-Hartman 2019-03-29 15:47:40 +01:00
parent 4b0a2c5ff7
commit 0eae4686a1
2 changed files with 0 additions and 10 deletions
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7
drivers/tty/pty.c
View File

@ -116,12 +116,6 @@ static int pty_write(struct tty_struct *tty, const unsigned char *buf, int c)
if (tty->stopped)
return 0;
mutex_lock(&tty_mutex);
if (to->magic != TTY_MAGIC) {
mutex_unlock(&tty_mutex);
return -EIO;
}
if (c > 0) {
spin_lock_irqsave(&to->port->lock, flags);
/* Stuff the data into the input queue of the other end */
@ -131,7 +125,6 @@ static int pty_write(struct tty_struct *tty, const unsigned char *buf, int c)
tty_flip_buffer_push(to->port);
spin_unlock_irqrestore(&to->port->lock, flags);
}
mutex_unlock(&tty_mutex);
return c;
}

3
drivers/tty/tty_io.c
View File

@ -1448,13 +1448,10 @@ static void release_one_tty(struct work_struct *work)
struct tty_driver *driver = tty->driver;
struct module *owner = driver->owner;
mutex_lock(&tty_mutex);
if (tty->ops->cleanup)
tty->ops->cleanup(tty);
tty->magic = 0;
mutex_unlock(&tty_mutex);
tty_driver_kref_put(driver);
module_put(owner);