Messages in this thread Patch in this message | | | From | Alan Cox <> | Subject | [PATCH 6/9] tty: fix sanity check | Date | Tue, 16 Jun 2009 17:01:33 +0100 |
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From: Alan Cox <alan@linux.intel.com>
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> ---
drivers/char/tty_io.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-)
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index 939e198..a3afa0c 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -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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