Subject: Re: bug#12478: cat SEGV when I press Ctrl-Alt-SysRq-1 on text console

From: Bob Proulx <[email-masked]>
Date: Tue, 2 Oct 2012 10:20:08 -0600

Rafal W. wrote:
> So in summary the process is killed if the key is not handled by anything
> else.

I don't agree with that conclusion.  It has not been determined what
action is happening for you with Alt-SysRq-{1,2,3,4,7,8,9,0} and
without that knowledge I don't believe a conclusion can be made.

I think it likely that on your system those keys are getting mapped to
C-\ which is supposed to generate SIGQUIT which is a debugging feature
which is supposed to cause applications to core dump so that the core
image can be examined.

> In this case Alt-SysRq 1-4,7-9,0 are not handled by kernel somehow.

And they are not for me either.  But nothing else happens for me either.

> So then code of release key of Alt-SysRq is sent. Pressing just Alt-SysRq
> is killing the process as well. Which shouldn't happen I guess.

But that is contrary to what you said before where you said:

> Alt-SysRq-m and other letters works, doesn't kill the process.

I think things have reduced to the point where your next step would be
to take your current key mapping issue to your software distribution
community and see what they say.  The behavior on your system is
different from the behavior on other systems and therefore this seems
to me like a system dependent issue.  That means that you need to
address the key mapping problem within your software distribution.

This clearly isn't a bug in any of the coreutils.  I am going to go
ahead and mark the bug as closed.  Feel free to continue the
discussion as I just did with this message.  It will still reach all
of the participants.

Bob