patch "tty: fix memory leak in vc_deallocate" added to tty-testing

patch "tty: fix memory leak in vc_deallocate" added to tty-testing

[gregkh]

This is a note to let you know that I've just added the patch titled

    tty: fix memory leak in vc_deallocate

to my tty git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git
in the tty-testing branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will be merged to the tty-next branch sometime soon,
after it passes testing, and the merge window is open.

If you have any questions about this process, please let me know.


From 211b4d42b70f1c1660feaa968dac0efc2a96ac4d Mon Sep 17 00:00:00 2001
From: Pavel Skripkin <paskripkin@gmail.com>
Date: Sun, 28 Mar 2021 00:44:43 +0300
Subject: tty: fix memory leak in vc_deallocate

syzbot reported memory leak in tty/vt.
The problem was in VT_DISALLOCATE ioctl cmd.
After allocating unimap with PIO_UNIMAP it wasn't
freed via VT_DISALLOCATE, but vc_cons[currcons].d was
zeroed.

Reported-by: syzbot+bcc922b19ccc64240b42@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20210327214443.21548-1-paskripkin@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/tty/vt/vt.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index d9366da51e06..01645e87b3d5 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -1381,6 +1381,7 @@ struct vc_data *vc_deallocate(unsigned int currcons)
 		atomic_notifier_call_chain(&vt_notifier_list, VT_DEALLOCATE, &param);
 		vcs_remove_sysfs(currcons);
 		visual_deinit(vc);
+		con_free_unimap(vc);
 		put_pid(vc->vt_pid);
 		vc_uniscr_set(vc, NULL);
 		kfree(vc->vc_screenbuf);
-- 
2.31.1