diff options
| author | Alan Cox <alan@llwyncelyn.cymru> | 2017-06-02 14:49:30 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-06-03 11:43:46 +0200 |
| commit | 8a8dabf2dd68caff842d38057097c23bc514ea6e (patch) | |
| tree | 98e019474882e4f4ea47ac77e162c86f3540c726 /drivers/tty/Makefile | |
| parent | tty: reserve N_SPEAKUP number (diff) | |
| download | linux-8a8dabf2dd68caff842d38057097c23bc514ea6e.tar.xz linux-8a8dabf2dd68caff842d38057097c23bc514ea6e.zip | |
tty: handle the case where we cannot restore a line discipline
Historically the N_TTY driver could never fail but this has become broken over
time. Rather than trying to rewrite half the ldisc layer to fix the breakage
introduce a second level of fallback with an N_NULL ldisc which cannot fail,
and thus restore the guarantees required by the ldisc layer.
We still try and fail to N_TTY first. It's much more useful to find yourself
back in your old ldisc (first attempt) or in N_TTY (second attempt), and while
I'm not aware of any code out there that makes those assumptions it's good to
drive(r) defensively.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Tested-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/Makefile')
| -rw-r--r-- | drivers/tty/Makefile | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/tty/Makefile b/drivers/tty/Makefile index f02becdb3e33..8689279afdf1 100644 --- a/drivers/tty/Makefile +++ b/drivers/tty/Makefile @@ -1,6 +1,7 @@ obj-$(CONFIG_TTY) += tty_io.o n_tty.o tty_ioctl.o tty_ldisc.o \ tty_buffer.o tty_port.o tty_mutex.o \ - tty_ldsem.o tty_baudrate.o tty_jobctrl.o + tty_ldsem.o tty_baudrate.o tty_jobctrl.o \ + n_null.o obj-$(CONFIG_LEGACY_PTYS) += pty.o obj-$(CONFIG_UNIX98_PTYS) += pty.o obj-$(CONFIG_AUDIT) += tty_audit.o |