releases/4.19.35/tty-mark-siemens-r3964-line-discipline-as-broken.patch

   1 From c7084edc3f6d67750f50d4183134c4fb5712a5c8 Mon Sep 17 00:00:00 2001
   2 From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
   3 Date: Fri, 5 Apr 2019 15:39:26 +0200
   4 Subject: tty: mark Siemens R3964 line discipline as BROKEN
   5
   6 From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
   7
   8 commit c7084edc3f6d67750f50d4183134c4fb5712a5c8 upstream.
   9
  10 The n_r3964 line discipline driver was written in a different time, when
  11 SMP machines were rare, and users were trusted to do the right thing.
  12 Since then, the world has moved on but not this code, it has stayed
  13 rooted in the past with its lovely hand-crafted list structures and
  14 loads of "interesting" race conditions all over the place.
  15
  16 After attempting to clean up most of the issues, I just gave up and am
  17 now marking the driver as BROKEN so that hopefully someone who has this
  18 hardware will show up out of the woodwork (I know you are out there!)
  19 and will help with debugging a raft of changes that I had laying around
  20 for the code, but was too afraid to commit as odds are they would break
  21 things.
  22
  23 Many thanks to Jann and Linus for pointing out the initial problems in
  24 this codebase, as well as many reviews of my attempts to fix the issues.
  25 It was a case of whack-a-mole, and as you can see, the mole won.
  26
  27 Reported-by: Jann Horn <jannh@google.com>
  28 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  29 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
  30
  31 ---
  32  drivers/char/Kconfig |    2 +-
  33  1 file changed, 1 insertion(+), 1 deletion(-)
  34
  35 --- a/drivers/char/Kconfig
  36 +++ b/drivers/char/Kconfig
  37 @@ -343,7 +343,7 @@ config XILINX_HWICAP
  38
  39  config R3964
  40         tristate "Siemens R3964 line discipline"
  41 -       depends on TTY
  42 +       depends on TTY && BROKEN
  43         ---help---
  44           This driver allows synchronous communication with devices using the
  45           Siemens R3964 packet protocol. Unless you are dealing with special