From: Matthias Reichl <hias@horus.com>
To: Jiri Slaby <jirislaby@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Samuel Thibault <samuel.thibault@ens-lyon.org>,
linux-kernel@vger.kernel.org, Matthias Reichl <hias@horus.com>
Subject: [PATCH] tty: fix crash in release_tty if tty->port is not set
Date: Thu, 5 Nov 2020 13:34:32 +0100 [thread overview]
Message-ID: <20201105123432.4448-1-hias@horus.com> (raw)
Commit 2ae0b31e0face ("tty: don't crash in tty_init_dev when missing
tty_port") didn't fully prevent the crash as the cleanup path in
tty_init_dev() calls release_tty() which dereferences tty->port
without checking it for non-null.
Add tty->port checks to release_tty to avoid the kernel crash.
Fixes: 2ae0b31e0face ("tty: don't crash in tty_init_dev when missing tty_port")
Signed-off-by: Matthias Reichl <hias@horus.com>
---
drivers/tty/tty_io.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 7a4c02548fb3f..9f8b9a567b359 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -1515,10 +1515,12 @@ static void release_tty(struct tty_struct *tty, int idx)
tty->ops->shutdown(tty);
tty_save_termios(tty);
tty_driver_remove_tty(tty->driver, tty);
- tty->port->itty = NULL;
+ if (tty->port)
+ tty->port->itty = NULL;
if (tty->link)
tty->link->port->itty = NULL;
- tty_buffer_cancel_work(tty->port);
+ if (tty->port)
+ tty_buffer_cancel_work(tty->port);
if (tty->link)
tty_buffer_cancel_work(tty->link->port);
--
2.20.1
reply other threads:[~2020-11-05 12:34 UTC|newest]
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