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authorGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-03-29 15:47:40 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-03-29 15:47:40 +0100
commit0eae4686a128d87503863a261e84887750c8bc68 (patch)
tree54a82e36439c0aca8e6a4389c5ea683b2887b1ab /drivers/tty
parent4b0a2c5ff7215206ea6135a405f17c5f6fca7d00 (diff)
downloadlinux-0eae4686a128d87503863a261e84887750c8bc68.tar.bz2
Revert "tty: pty: Fix race condition between release_one_tty and pty_write"
This reverts commit b9ca5f8560af244489b4a1bc1ae88b341f24bc95 as 0-day shows it has a circular locking dependency. Fixes: b9ca5f8560af ("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>
Diffstat (limited to 'drivers/tty')
-rw-r--r--drivers/tty/pty.c7
-rw-r--r--drivers/tty/tty_io.c3
2 files changed, 0 insertions, 10 deletions
diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c
index ef72031ab5b9..00099a8439d2 100644
--- a/drivers/tty/pty.c
+++ b/drivers/tty/pty.c
@@ -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;
}
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index c27777f3b8c4..5fa250157025 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -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);