ACK: [SRU][Groovy][PATCH 0/2] Revert tty changes to fix regression

[Colin Ian King]

On 21/04/2021 18:16, Kleber Sacilotto de Souza wrote:
> BugLink: https://bugs.launchpad.net/bugs/1925290
> 
> [Impact]
> Testcase hangup01 from ubuntu_ltp_stable.pty is failing on Groovy 5.8.0-51.57.
> 
> Test case failed with:
>  hangup01 1 TFAIL : hangup01.c:132: unexpected message 3
>  tag=hangup01 stime=1618856629 dur=1 exit=exited stat=1
> 
> It was found that the regression was introduced by the following commits applied
> via stable uddates:
> 
> dd78b0c483e3 tty: implement read_iter
> 3b830a9c34d5 tty: convert tty_ldisc_ops 'read()' function to take a kernel pointer
> 
> These patches were applied via bug 1921960 ("Groovy update: upstream stable
> patchset 2021-03-30").
> 
> [Fix]
> Revert the patches mentioned above until a fix can be found.
> 
> [Test case]
> Run the pty testsuite from ubuntu_ltp_stable.
> 
> [Where problems could occur]
> If reverting these two patches is not enough to bring the code to the behavior
> of the tty driver before 5.8.0-51.57 then remaining issues could still be
> present on the tty code. Those issues should be caught by the ltp testcases
> though.
> 
> Kleber Sacilotto de Souza (2):
>   UBUNTU: SAUCE: Revert "tty: implement read_iter"
>   UBUNTU: SAUCE: Revert "tty: convert tty_ldisc_ops 'read()' function to
>     take a kernel pointer"
> 
>  drivers/bluetooth/hci_ldisc.c | 34 +++++++--------
>  drivers/input/serio/serport.c |  4 +-
>  drivers/net/ppp/ppp_async.c   |  3 +-
>  drivers/net/ppp/ppp_synctty.c |  3 +-
>  drivers/tty/n_gsm.c           |  3 +-
>  drivers/tty/n_hdlc.c          | 60 ++++++++-----------------
>  drivers/tty/n_null.c          |  3 +-
>  drivers/tty/n_r3964.c         | 10 +++--
>  drivers/tty/n_tracerouter.c   |  4 +-
>  drivers/tty/n_tracesink.c     |  4 +-
>  drivers/tty/n_tty.c           | 82 ++++++++++++++++++++---------------
>  drivers/tty/tty_io.c          | 82 +++++------------------------------
>  include/linux/tty_ldisc.h     |  3 +-
>  net/nfc/nci/uart.c            |  3 +-
>  14 files changed, 111 insertions(+), 187 deletions(-)
> 

A revert seems like the sensible way forward at this juncture.

Acked-by: Colin Ian King <colin.king at canonical.com>