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authorAlan Cox <alan@linux.intel.com>2009-06-16 17:01:33 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2009-06-16 12:01:16 -0700
commit1aa4bed82a684308f54bf782cffaecd4b1dc3cf4 (patch)
treea629a5c25caf3880a23bda9af4404c86a8a5ad00
parent762faaed91e4ea4a3c34bc58f3221d9487acb470 (diff)
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>
-rw-r--r--drivers/char/tty_io.c2
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;
}