[grsec] 2.6.10-as2 + grsec 2.1.1 gives userspace segfaults

[Igmar Palsenberg]

> what's your distro/glibc version?

An highly modded RH 7.1 install, and debian stable / testing. The distrib 
/ libc version seems unrelated at first sight.

Testing + Unstable has libc 2.3.2
RH71 has 2.2.4

> also, could you turn off/on the
> various randomization options and see which makes the problem go
> away (if anything)? thing is, ld.so used to have a bug in its use
> of brk() that would cause such issues, but that should have been
> worked around in PaX for some time now (you could try to comment
> out the brk randomization code in fs/binfmt_elf.c, it's a 1-liner).

I'll play with it. Kernel compiles go fast on this machine :)

> with that said, i too saw an 'interesting' crash while compiling
> qt and it had all the symptoms of the above mentioned (and supposedly)
> fixed bug... so i don't know. what kind of applications crash on
> you?

It usually starts with gcc, and from then on crashes seems to occure more 
frequently. I've had gcc, make, X crashes until now. gcc usually triggers 
it. It's not a hardware issue, I know that for sure.

> would it be possible to acquire a /proc/pid/maps file somehow
> at the time of the crash (like, run the app in gdb which will catch
> the sigsegv then you can get the maps, or maybe a readelf -l on
> the coredump itself, but that has less information)? also, are you
> using preempt or 4k stacks or anything 'weird'?

Hmm.. I'll see what I can do. I usually run while [ 1 = 1 ]; do make 
clean; make; done

until it crashes. I'll keep you posted.



	Igmar