From: "KAMBAROV, ZAUR" We add a check of the return value of tty_ldisc_ref(), which is checked 7 out of 8 times, e.g.: 149 ld = tty_ldisc_ref(tty); 150 if (ld != NULL) { 151 if (ld->set_termios) 152 (ld->set_termios)(tty, &old_termios); 153 tty_ldisc_deref(ld); 154 } This defect was found automatically by Coverity Prevent, a static analysis tool. (akpm: presumably `ld' is never NULL. Oh well) Signed-off-by: Zaur Kambarov Cc: Alan Cox Signed-off-by: Andrew Morton --- drivers/char/tty_ioctl.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff -puN drivers/char/tty_ioctl.c~coverity-tty_ldisc_ref-return-null-check drivers/char/tty_ioctl.c --- 25/drivers/char/tty_ioctl.c~coverity-tty_ldisc_ref-return-null-check 2005-06-24 22:21:09.000000000 -0700 +++ 25-akpm/drivers/char/tty_ioctl.c 2005-06-24 22:21:09.000000000 -0700 @@ -476,11 +476,11 @@ int n_tty_ioctl(struct tty_struct * tty, ld = tty_ldisc_ref(tty); switch (arg) { case TCIFLUSH: - if (ld->flush_buffer) + if (ld && ld->flush_buffer) ld->flush_buffer(tty); break; case TCIOFLUSH: - if (ld->flush_buffer) + if (ld && ld->flush_buffer) ld->flush_buffer(tty); /* fall through */ case TCOFLUSH: _