I just bought a laptop (HP Pavilion 2G ram, AMD Turion X2) and put Ubuntu 9.04 on it.
I then, using Synaptic package manager, installed Maxima ( xmaxima 5.13.0. It seemed to work OK, so I tried to factor a big number to see how fast it was going. At this point I got an error message, so Tried a smaller number and it factored OK.
To make a long story sort , let me say that I tried many different tests, and I think there is a stack overflow problem.
factor( big numbers) fails
when I run the built in tests it fails on:
rtestnset.mac at test
map(lambda([x], apply("+",x)), integer_partitions(25));
set(25)$
but if I just run that test by itself , it passes the test.
rtest15 problem 192 fails : it also uses factor.
I have Ubuntu 8.04 on a desktop and ran all the same test on it and all worked fine.
This was all done with xmaxima 5.13.0, same maxima in both machines.
I then looked at what was new in Ubuntu 9.04, and found:
Hardened Kernels
Hardened kernels are modifications to the Linux kernel that add additional security measures. This could include:
The randomization of ports,
memory addresses, process ID's, and other information that is typically
predictable. This can thwart off many types of common attacks.Identify and prevent buffer overflow attacks from resulting in
compromise by killing compromised processes (PaX bundled with
grsecurity, or Redhat's Exec-Shield combined with prelink
randomization). Edgy and higher contain GCC stack protection enforced
in most applications, but is unable to respond to several kinds of
attacks that a kernel-layer enforcer could. Likewise, PaX and friends
have weakness that GCC stack protection helps cover, so the two work
great as a duo.Hiding information that Linux usually allows everyone to see,
including all running processes on the system, load averages, CPU info,
IP addresses, etc. Obscuring this information can help keep attackers
"in the dark" so to speak.More aggressive enforcement of buffer overflow protection than what Ubuntu's standard gcc stack protector can do.Adding additional restrictions on the capabilities of regular users that prevent channels of attack.Additional permissions systems that allow finer-grained tuning of various aspects of Linux.
particularly this statement.
"Edgy and higher contain GCC stack protection enforced
in most applications,"
So now my questions;
Has anybody else seen this problem?
How do I debug this more to prove it is a stack problem?
Can you monitor the stack from Ubuntu?
It is not a memory problem, memory usage was at about 30% when the problem first show up, an I ran Octave and used up 50% of the memory and then ran Maxima again and it failed at exactly the same steps.
Doug Stewart