diff options
| author | Alan Cox <alan@linux.intel.com> | 2009-06-16 18:01:33 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-06-16 21:01:16 +0200 |
| commit | 1aa4bed82a684308f54bf782cffaecd4b1dc3cf4 (patch) | |
| tree | a629a5c25caf3880a23bda9af4404c86a8a5ad00 /drivers/char | |
| parent | pty: Narrow the race on ldisc locking (diff) | |
| download | linux-1aa4bed82a684308f54bf782cffaecd4b1dc3cf4.tar.xz linux-1aa4bed82a684308f54bf782cffaecd4b1dc3cf4.zip | |
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>
Diffstat (limited to 'drivers/char')
| -rw-r--r-- | 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 939e198d7670..a3afa0c387cd 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; } |