diff options
| author | Dmitry Safonov <dima@arista.com> | 2019-01-09 01:17:40 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-01-23 08:10:53 +0100 |
| commit | a172c5d82643f18080af2aba21c897467e5cf1de (patch) | |
| tree | 2ffc3cfff89168264d93c28726cf7d5cc8627175 /fs/proc/array.c | |
| parent | 383cf6479d489b7becc64b4860cef94dfd19ca5e (diff) | |
tty: Don't hold ldisc lock in tty_reopen() if ldisc present
commit d3736d82e8169768218ee0ef68718875918091a0 upstream.
Try to get reference for ldisc during tty_reopen().
If ldisc present, we don't need to do tty_ldisc_reinit() and lock the
write side for line discipline semaphore.
Effectively, it optimizes fast-path for tty_reopen(), but more
importantly it won't interrupt ongoing IO on the tty as no ldisc change
is needed.
Fixes user-visible issue when tty_reopen() interrupted login process for
user with a long password, observed and reported by Lukas.
Fixes: c96cf923a98d ("tty: Don't block on IO when ldisc change is pending")
Fixes: 83d817f41070 ("tty: Hold tty_ldisc_lock() during tty_reopen()")
Cc: Jiri Slaby <jslaby@suse.com>
Reported-by: Lukas F. Hartmann <lukas@mntmn.com>
Tested-by: Lukas F. Hartmann <lukas@mntmn.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/proc/array.c')
0 files changed, 0 insertions, 0 deletions