Commit 1aa4bed8 authored Jun 16, 2009 by Alan Cox Committed by Linus Torvalds Jun 16, 2009

tty: fix sanity check

The WARN_ON() that was added to tty_reopen can be triggered in the specific
case of a hangup occurring during a re-open of a tty which is not in the
middle of being otherwise closed.

In that case however the WARN() is bogus as we don't hold the neccessary
locks to make a correct decision.

The case we should be checking is "if the ldisc is not changing and reopen
is occuring". We could drop the WARN_ON but for the moment the debug is more
valuable even if it means taking a mutex as it will find any other cases.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 762faaed

drivers/char/tty_io.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -1263,7 +1263,9 @@ static int tty_reopen(struct tty_struct *tty)
		tty->count++;
		tty->driver = driver; /* N.B. why do this every time?? */

		mutex_lock(&tty->ldisc_mutex);
		WARN_ON(!test_bit(TTY_LDISC, &tty->flags));
		mutex_unlock(&tty->ldisc_mutex);

		return 0;
		}

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