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authorGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-02-14 14:36:04 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-02-14 14:36:04 -0800
commit249f3c4fe4fdef159d3f9b3f7a6c41a92103c860 (patch)
tree58abfec8444741fd3bd403a908be50c4f63d4842 /drivers/tty/pty.c
parent54573c4a073ff510d028f423ed3074573c7d9437 (diff)
parent18558cae0272f8fd9647e69d3fec1565a7949865 (diff)
Merge 4.5-rc4 into tty-next
We want the fixes in here, and this resolves a merge error in tty_io.c 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 78170e7aa3a3..e16a49b507ef 100644
--- a/drivers/tty/pty.c
+++ b/drivers/tty/pty.c
@@ -663,7 +663,14 @@ static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty)
/* this is called once with whichever end is closed last */
static void pty_unix98_remove(struct tty_driver *driver, 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 = {
@@ -753,6 +760,18 @@ 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,

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