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Commit 1aa4bed8 authored by Alan Cox's avatar Alan Cox Committed by Linus Torvalds
Browse files

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: default avatarAlan Cox <alan@linux.intel.com>
Signed-off-by: default avatarLinus 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;

}