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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        syzbot+bcc922b19ccc64240b42@syzkaller.appspotmail.com,
        Pavel Skripkin <paskripkin@gmail.com>
Subject: [PATCH 5.10 288/299] tty: fix memory leak in vc_deallocate
Date:   Mon, 10 May 2021 12:21:25 +0200
Message-Id: <20210510102014.429410247@linuxfoundation.org>
In-Reply-To: <20210510102004.821838356@linuxfoundation.org>
References: <20210510102004.821838356@linuxfoundation.org>
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From: Pavel Skripkin <paskripkin@gmail.com>

commit 211b4d42b70f1c1660feaa968dac0efc2a96ac4d upstream.

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(+)

--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -1382,6 +1382,7 @@ struct vc_data *vc_deallocate(unsigned i
 		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);