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Message-ID: <20090616160118.10041.47059.stgit@t61.ukuu.org.uk> Date: Tue, 16 Jun 2009 17:01:33 +0100 From: Alan Cox <alan@...rguk.ukuu.org.uk> To: torvalds@...ux-foundation.org, linux-kernel@...r.kernel.org Subject: [PATCH 6/9] tty: fix sanity check From: Alan Cox <alan@...ux.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@...ux.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; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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