Jiri Slaby acfa747baf TTY: open/hangup race fixup ... Like in the "TTY: don't allow reopen when ldisc is changing" patch, this one fixes a TTY WARNING as described in the option 1) there: 1) __tty_hangup from tty_ldisc_hangup to tty_ldisc_enable. During this section tty_lock is held. However tty_lock is temporarily dropped in the middle of the function by tty_ldisc_hangup. The fix is to introduce a new flag which we set during the unlocked window and check it in tty_reopen too. The flag is TTY_HUPPING and is cleared after TTY_HUPPED is set. While at it, remove duplicate TTY_HUPPED set_bit. The one after calling ops->hangup seems to be more correct. But anyway, we hold tty_lock, so there should be no difference. Also document the function it does that kind of crap. Nicely reproducible with two forked children: static void do_work(const char *tty) { if (signal(SIGHUP, SIG_IGN) == SIG_ERR) exit(1); setsid(); while (1) { int fd = open(tty, O_RDWR|O_NOCTTY); if (fd < 0) continue; if (ioctl(fd, TIOCSCTTY)) continue; if (vhangup()) continue; close(fd); } exit(0); } Signed-off-by: Jiri Slaby <jslaby@suse.cz> Reported-by: <Valdis.Kletnieks@vt.edu> Reported-by: Kyle McMartin <kyle@mcmartin.ca> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: stable <stable@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>		2010-11-29 14:52:48 -08:00
..
vt	vcs: make proper usage of the poll flags	2010-11-11 10:51:35 -08:00
Makefile	TTY: create drivers/tty/vt and move the vt code there	2010-11-05 08:16:52 -07:00
n_gsm.c	n_gsm: Fix length handling	2010-11-11 11:06:09 -08:00
n_hdlc.c
n_r3964.c
n_tty.c
pty.c
sysrq.c
tty_audit.c
tty_buffer.c	tty: prevent DOS in the flush_to_ldisc	2010-11-09 15:02:02 -08:00
tty_io.c	TTY: open/hangup race fixup	2010-11-29 14:52:48 -08:00
tty_ioctl.c
tty_ldisc.c	TTY: ldisc, fix open flag handling	2010-11-29 14:51:54 -08:00
tty_mutex.c
tty_port.c