Re: Linux-1.3.19

Linus Torvalds (Linus.Torvalds@cs.Helsinki.FI)
Thu, 17 Aug 1995 10:26:52 +0300

Ryan Smith-Roberts: "Re: Linux-1.3.19" (Aug 16, 11:25):
> On Tue, 15 Aug 1995, Linus Torvalds wrote:
>
> > I have gotten a few reports of "strace" completely freezing a few
> > machines. So far these reports have had two things in common: a Pentium
> > processor and gcc-2.7.0. It may be that the Pentium 4MB page table code
> > does strange things on some machines, or that gcc-2.7.0 compiles the
> > code to something I never meant it to be.. I'd like to hear if the
> > people that can make this happen could try an older compiler to check.
>
> I believe that on the net someone specified (was it Thomas Koenig?) they
> had used 2.6.3 to do it and it was still there. Also, unmounting /proc
> (with the resulting failed open on /proc/[pid]/mem) was armor against the
> bug.

Yes. It is fixed in 1.3.20 (at least one report of success). The
common problem wasn't gcc-2.7.0, but a newer version of strace than the
one I had that used /proc/<pid>/mem for some new things.

1.3.20 fixes read() on /proc/<pid>/mem that used to do bad things (I'll
have to make a 1.2.14 with this fix as well: it's a _bad_ security hole
as well).

> Also note that, with me and as I remember with everyone else, the bug is
> not a freeze bug, it is a reboot bug.

It rebooted for some, froze for some, it seems. Anyway, please test
1.3.20: I'm reasonably sure it's fixed.

> > Anything else that has problems with this kernel?
>
> I'm getting cross-VT corruption, where the text on one VT appears on
> another (which is never active, and it doesn't happen to that VT after I
> switch back to it, for a while).

Interesting.. Ugh. This is a new one. Are you sure your hardware is
stable?

Linus