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authorGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-02-23 01:46:24 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-02-23 01:46:24 +0300
commitbb27d4998a9e8767674e8eda225c82cc149e5bc8 (patch)
treedcabb8b8cc510003637323b30ed414b1a1ec86f6 /drivers/tty/pty.c
parent9676e84dfd641e3366a41f2c45ac5c55dbac820f (diff)
parent35bf7692e765c2275bf93fe573f7ca868ab73453 (diff)
downloadlinux-bb27d4998a9e8767674e8eda225c82cc149e5bc8.tar.xz
Merge char-misc-next into staging-next
This resolves the merge issues and confusions people were having with the goldfish drivers due to changes for them showing up in two different trees. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/pty.c')
-rw-r--r--drivers/tty/pty.c21
1 files changed, 20 insertions, 1 deletions
diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c
index b3110040164a..2348fa613707 100644
--- a/drivers/tty/pty.c
+++ b/drivers/tty/pty.c
@@ -681,7 +681,14 @@ static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
/* this is called once with whichever end is closed last */
static void pty_unix98_shutdown(struct tty_struct *tty)
{
- devpts_kill_index(tty->driver_data, tty->index);
+ struct inode *ptmx_inode;
+
+ if (tty->driver->subtype == PTY_TYPE_MASTER)
+ ptmx_inode = tty->driver_data;
+ else
+ ptmx_inode = tty->link->driver_data;
+ devpts_kill_index(ptmx_inode, tty->index);
+ devpts_del_ref(ptmx_inode);
}
static const struct tty_operations ptm_unix98_ops = {
@@ -773,6 +780,18 @@ static int ptmx_open(struct inode *inode, struct file *filp)
set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
tty->driver_data = inode;
+ /*
+ * In the case where all references to ptmx inode are dropped and we
+ * still have /dev/tty opened pointing to the master/slave pair (ptmx
+ * is closed/released before /dev/tty), we must make sure that the inode
+ * is still valid when we call the final pty_unix98_shutdown, thus we
+ * hold an additional reference to the ptmx inode. For the same /dev/tty
+ * last close case, we also need to make sure the super_block isn't
+ * destroyed (devpts instance unmounted), before /dev/tty is closed and
+ * on its release devpts_kill_index is called.
+ */
+ devpts_add_ref(inode);
+
tty_add_file(tty, filp);
slave_inode = devpts_pty_new(inode,