diff options
| author | Peter Hurley <peter@hurleysoftware.com> | 2013-06-15 13:04:48 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-07-24 01:38:34 +0200 |
| commit | 36697529b5bbe36911e39a6309e7a7c9250d280a (patch) | |
| tree | 5cbffa976994cb798e00d60eccb46c6cafc369a1 /drivers/tty/tty_buffer.c | |
| parent | tty: Add lock/unlock ldisc pair functions (diff) | |
| download | linux-36697529b5bbe36911e39a6309e7a7c9250d280a.tar.xz linux-36697529b5bbe36911e39a6309e7a7c9250d280a.zip | |
tty: Replace ldisc locking with ldisc_sem
Line discipline locking was performed with a combination of
a mutex, a status bit, a count, and a waitqueue -- basically,
a rw semaphore.
Replace the existing combination with an ld_semaphore.
Fixes:
1) the 'reference acquire after ldisc locked' bug
2) the over-complicated halt mechanism
3) lock order wrt. tty_lock()
4) dropping locks while changing ldisc
5) previously unidentified deadlock while locking ldisc from
both linked ttys concurrently
6) previously unidentified recursive deadlocks
Adds much-needed lockdep diagnostics.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/tty_buffer.c')
| -rw-r--r-- | drivers/tty/tty_buffer.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c index 9121c1f7aeef..a42a028a9d4e 100644 --- a/drivers/tty/tty_buffer.c +++ b/drivers/tty/tty_buffer.c @@ -429,7 +429,7 @@ static void flush_to_ldisc(struct work_struct *work) return; disc = tty_ldisc_ref(tty); - if (disc == NULL) /* !TTY_LDISC */ + if (disc == NULL) return; spin_lock_irqsave(&buf->lock, flags); |