Re: bash randomly logs out on VT / serial console

[Russell King]

On Sun, Jan 01, 2017 at 09:14:45PM -0500, Chet Ramey wrote:
> On 1/1/17 4:01 PM, rmk@armlinux.org.uk wrote:
> > Bash Version: 4.3
> > Patch Level: 30
> > Release Status: release
> > 
> > Description:
> >     Running:
> >             while :; do s=$(sleep .005 | cat); echo $s; done | uniq
> >     in a login shell on a virtual terminal or serial console results
> >     in the shell randomly logging out after ^C.
> 
> I believe this is fixed in bash-4.4.

Thank you for your reply.

However, while testing bash-4.4 with the five additional patches (bringing
it to 4.4.5) shows that it is not fixed in bash-4.4 - see below.  The line
from __tty_check_change() is from the debug I added to the kernel, which
shows that the reason for the EIO error is because the tty pgrp doesn't
match the process' pgrp.

# ps -ef | grep ttyS0
root     29257     1  0 10:44 ttyS0    00:00:00 /bin/login --
root     29293 29257  0 10:45 ttyS0    00:00:00 -bash

root@mcbin:~# while :; do s=$(sleep .005 | cat); echo $s; done | uniq

^C
root@mcbin:~# while :; do s=$(sleep .005 | cat); echo $s; done | uniq

^C
root@mcbin:~# __tty_check_change: tty=ffffffc0e74bd800 current 
pgrp=29293(ffffffc0e795fc00) tty pgrp=29257(ffffffc0e795f080)
logout

-- 
Russell King