Johannes Weiner e65c62b137 tty: fall back to N_NULL if switching to N_TTY fails during hangup ... We have seen NULL-pointer dereference crashes in tty->disc_data when the N_TTY fallback driver failed to open during hangup. The immediate cause of this open to fail has been addressed in the preceding patch to vmalloc(), but this code could be more robust. As Alan pointed out in commit 8a8dabf2dd ("tty: handle the case where we cannot restore a line discipline"), the N_TTY driver, historically the safe fallback that could never fail, can indeed fail, but the surrounding code is not prepared to handle this. To avoid crashes he added a new N_NULL driver to take N_TTY's place as the last resort. Hook that fallback up to the hangup path. Update tty_ldisc_reinit() to reflect the reality that n_tty_open can indeed fail. Link: http://lkml.kernel.org/r/20171004185959.GC2136@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Alan Cox <alan@llwyncelyn.cymru> Cc: Christoph Hellwig <hch@lst.de> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2017-10-13 16:18:33 -07:00
..
hvc	powerpc updates for 4.14	2017-09-07 10:15:40 -07:00
ipwireless
serdev
serial	serial: sccnxp: Fix error handling in sccnxp_probe()	2017-09-18 18:19:21 +02:00
vt
amiserial.c
bfin_jtag_comm.c
cyclades.c
ehv_bytechan.c
goldfish.c	tty: goldfish: Implement support for kernel 'earlycon' parameter	2017-08-31 18:58:45 +02:00
isicom.c
Kconfig	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-next	2017-09-10 09:57:23 -07:00
Makefile
metag_da.c
mips_ejtag_fdc.c	tty: mips_ejtag_fdc: constify mips_cdmm_device_id	2017-08-28 20:51:22 +02:00
moxa.c
moxa.h
mxser.c	mxser: fix timeout calculation for low rates	2017-09-18 18:19:20 +02:00
mxser.h
n_gsm.c	tty: n_gsm: Add compat_ioctl	2017-08-28 20:51:22 +02:00
n_hdlc.c
n_null.c
n_r3964.c
n_tracerouter.c
n_tracesink.c
n_tracesink.h
n_tty.c
nozomi.c
pty.c	TTY/Serial updates for 4.14-rc1	2017-09-05 10:30:48 -07:00
rocket_int.h
rocket.c
rocket.h
synclink_gt.c
synclink.c
synclinkmp.c
sysrq.c
tty_audit.c
tty_baudrate.c
tty_buffer.c
tty_io.c	Staging/IIO driver updates for 4.14-rc1	2017-09-05 10:36:26 -07:00
tty_ioctl.c
tty_jobctrl.c
tty_ldisc.c	tty: fall back to N_NULL if switching to N_TTY fails during hangup	2017-10-13 16:18:33 -07:00
tty_ldsem.c
tty_mutex.c
tty_port.c
vcc.c	sparc64: vcc: make ktermios const	2017-08-29 15:10:44 -07:00