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authorPeter Hurley <peter@hurleysoftware.com>2016-02-05 10:49:36 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-02-06 16:56:46 -0800
commite9036d0662360cd4c79578565ce422ed5872f301 (patch)
treede3a6332fd92f6a8992440467988f6844bd270c9 /drivers/tty
parent36f90b0a2ddd60823fe193a85e60ff1906c2a9b3 (diff)
downloadlinux-e9036d0662360cd4c79578565ce422ed5872f301.tar.bz2
tty: Drop krefs for interrupted tty lock
When the tty lock is interrupted on attempted re-open, 2 tty krefs are still held. Drop extra kref before returning failure from tty_lock_interruptible(), and drop lookup kref before returning failure from tty_open(). Fixes: 0bfd464d3fdd ("tty: Wait interruptibly for tty lock on reopen") Reported-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
-rw-r--r--drivers/tty/tty_io.c3
-rw-r--r--drivers/tty/tty_mutex.c7
2 files changed, 7 insertions, 3 deletions
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 5cec01c75691..a7eacef1bd22 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -2066,13 +2066,12 @@ retry_open:
if (tty) {
mutex_unlock(&tty_mutex);
retval = tty_lock_interruptible(tty);
+ tty_kref_put(tty); /* drop kref from tty_driver_lookup_tty() */
if (retval) {
if (retval == -EINTR)
retval = -ERESTARTSYS;
goto err_unref;
}
- /* safe to drop the kref from tty_driver_lookup_tty() */
- tty_kref_put(tty);
retval = tty_reopen(tty);
if (retval < 0) {
tty_unlock(tty);
diff --git a/drivers/tty/tty_mutex.c b/drivers/tty/tty_mutex.c
index d2f3c4cd697f..dfa9ec03fa8e 100644
--- a/drivers/tty/tty_mutex.c
+++ b/drivers/tty/tty_mutex.c
@@ -21,10 +21,15 @@ EXPORT_SYMBOL(tty_lock);
int tty_lock_interruptible(struct tty_struct *tty)
{
+ int ret;
+
if (WARN(tty->magic != TTY_MAGIC, "L Bad %p\n", tty))
return -EIO;
tty_kref_get(tty);
- return mutex_lock_interruptible(&tty->legacy_mutex);
+ ret = mutex_lock_interruptible(&tty->legacy_mutex);
+ if (ret)
+ tty_kref_put(tty);
+ return ret;
}
void __lockfunc tty_unlock(struct tty_struct *tty)