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| author | Alan Cox <alan@llwyncelyn.cymru> | 2017-06-02 15:49:30 +0300 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2018-10-21 10:45:38 +0300 |
| commit | a6a35a2a03c2fecc1d6dbf552a262fa7321b7adf (patch) | |
| tree | a61123466c8fa4f67fd118d7ec0e7daaec8076a8 /drivers/tty/moxa.h | |
| parent | 2d377a2199617414a0599f8fe512b42a4967bdc3 (diff) | |
| download | linux-a6a35a2a03c2fecc1d6dbf552a262fa7321b7adf.tar.xz | |
tty: handle the case where we cannot restore a line discipline
commit 8a8dabf2dd68caff842d38057097c23bc514ea6e upstream.
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>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'drivers/tty/moxa.h')
0 files changed, 0 insertions, 0 deletions