From: Peter Hurley <peter@hurleysoftware.com>
Date: Fri, 1 Apr 2016 00:47:07 +0000 (-0700)
Subject: tty: Fix merge of "tty: Refactor tty_open()"
X-Git-Tag: v4.6-rc3~8^2
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=5e00bbfbc5ec21e87d24e206bba9fc2cbe6631a1;p=linux.git

tty: Fix merge of "tty: Refactor tty_open()"

Commit e9036d066236 ("tty: Drop krefs for interrupted tty lock")
fixed a tty reference counting problem introduced in
commit 0bfd464d3fdd ("tty: Wait interruptibly for tty lock on reopen"),
so v4.5.0 is correct.

However, commit d6203d0c7b73 ("tty: Refactor tty_open()") moved the
relevant code for 4.6-rc1; correct the merge.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 876878a7704f..9b04d72e752e 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -2049,14 +2049,13 @@ static struct tty_struct *tty_open_by_driver(dev_t device, struct inode *inode,
 	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;
 			tty = ERR_PTR(retval);
 			goto out;
 		}
-		/* safe to drop the kref from tty_driver_lookup_tty() */
-		tty_kref_put(tty);
 		retval = tty_reopen(tty);
 		if (retval < 0) {
 			tty_unlock(tty);