bugGNU Screen - Bugs: bug #42178, byobu >= 5.77 crashes screen...


bug #42178: byobu >= 5.77 crashes screen server process on pressing Ctrl-A c

Submitted by:  Axel Beckert <abe>
Submitted on:  Wed 23 Apr 2014 03:58:18 PM UTC  
Category:  Crash/Freeze/Infloop Severity:  3 - Normal
Priority:  5 - Normal Status:  None
Privacy:  Public Assigned to:  None
Open/Closed:  Open Release:  Cur Dev Sources
Fixed Release:  None Planned Release:  None
Work Required:  None

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Wed 23 Apr 2014 11:48:04 PM UTC, comment #2:

JFTR: The byobu code triggering this issue has been fixed in byobu's 5.78 release (which happened just a few minutes ago, triggered by this issue).

Axel Beckert <abe>
Wed 23 Apr 2014 06:48:22 PM UTC, comment #1:

Seems to be caused by ~/.config/byobu/keybindings,
still haven't tracked what exactly is wrong with it, but it seems to boil down to those lines:

escape "^Aa"
register x "^A"
bindkey "^A" eval "process x"

executing them in standalone screen session breaks it

seems like last one was changed recently
and changing it back fixes it

looking at it I suspect that screen goes into loop trying to echo "^A" and then processing it

It still needs checking, but following above theory escape key should probably be made unbindable so people can't break it.

Amadeusz Sławiński <amade>
Project Administrator
Wed 23 Apr 2014 03:58:18 PM UTC, original submission:

Initially reported in Ubuntu at https://bugs.launchpad.net/ubuntu/+source/screen/+bug/1274720 and also tracked in Debian at https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=745631

See http://byobu.co/ for more information about byobu, a screen and tmux wrapper. To reproduce at least byobu 5.77 is needed. 5.70 and lower versions are known to not trigger this issue.

The server processs of a GNU Screen session can be crashed by

1. rm -rf ~/.byobu
2. calling byobu-screen
3. pressing Ctrl-A to get byobu's Ctrl-A behaviour menu
4. choosing "screen behaviour"
5. pressing Ctrl-A c (some other Ctrl-A sequences work also)

Reproducible with the following versions of GNU Screen:

  • 4.2.0 (as patched in Debian tbh.)
  • commit db59704 (of 2012, as currently in Debian Stable)
  • current HEAD of the screen-v4 branch (commit fe8103c) without any further patches (just autoreconf + configure + make)

I haven't yet found a minimal .screenrc which triggers this issue without calling byobu first. But since there's a crash involved, it can't be byobu's fault alone...

Axel Beckert <abe>


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