From a0340703981baa6cc1e9c7c768095a0a4e718daf Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Wed, 19 Oct 2011 08:33:21 -0700 Subject: [PATCH] Revert "TTY: call tty_driver_lookup_tty unconditionally" This reverts commit 631180aca723cb92e128fdac5fd144e913ca84e5. It caused problems when /dev/tty is a pty: https://lkml.org/lkml/2011/10/12/401 Cc: Jiri Slaby Cc: stable Cc: Sukadev Bhattiprolu Cc: Alan Cox Signed-off-by: Greg Kroah-Hartman --- drivers/tty/tty_io.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index 0425170d9ed6..767ecbb4761a 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -1821,7 +1821,7 @@ int tty_release(struct inode *inode, struct file *filp) static int tty_open(struct inode *inode, struct file *filp) { - struct tty_struct *tty; + struct tty_struct *tty = NULL; int noctty, retval; struct tty_driver *driver; int index; @@ -1892,14 +1892,17 @@ retry_open: return -ENODEV; } got_driver: - /* check whether we're reopening an existing tty */ - tty = tty_driver_lookup_tty(driver, inode, index); - if (IS_ERR(tty)) { - tty_unlock(); - mutex_unlock(&tty_mutex); - tty_driver_kref_put(driver); - tty_free_file(filp); - return PTR_ERR(tty); + if (!tty) { + /* check whether we're reopening an existing tty */ + tty = tty_driver_lookup_tty(driver, inode, index); + + if (IS_ERR(tty)) { + tty_unlock(); + mutex_unlock(&tty_mutex); + tty_driver_kref_put(driver); + tty_free_file(filp); + return PTR_ERR(tty); + } } if (tty) {