Re: total freeze with framebuffer + X

Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz)
Sun, 28 Mar 1999 21:19:31 +0200 (CEST)

> > I found much more serious bug: xinit sometimes sends SIGKILL to xserver
> > when terminating. If your machine is under heavy load (make -j zImage) and
> > you correctly terminate windowmanager (not xserver), xinit kills xserver
> > with -9 and console is dead.
>
> This is actually supposed to be a feature: it's to protect against the server
> crashing and refusing to terminate, which will definitely leave your console
> unusable.
>
> (as an aside, make -j is completely useless unless you have 10-12 processors
> in your machine, except for stress-testing the kernel)

I know make -j is useless, but for stress-testing it's good.
BTW. Crashing under heavy load reminds me another well known operating
system ;-)

> > I think the kernel shouldn't allow users to send unmaskable signals to
> > suid programs.
>
> suid programs should be written to be able to deal with such circumstances.
> Unexpected events can happen due to any number of causes. suid programs don't
> have the excuse that they were run by root, so he can be blamed for anything
> that goes wrong.

What do you think X, dosemu, svgalib etc. should do to protect themselves
from -9 sent by the user? Yes, they can do setuid(0);setgid(0);, but it
protects them from all signals, what's not always good.

Mikulas Patocka

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