On Thu, Mar 29, 2007 at 08:00:49PM -0500, Tony Shadwick wrote: > I won't call it "fixed", but with much help from the guys in #openafs, > we did get things working.
That's great! ... > The stack size is set to 8192. We had to change that to unlimited, > then things started working, so ulimit -s unlimited. I see. > Ed, if you see this...any thoughts on what might cause this? Well, an OpenAFS process probably has a large array or similar data structure on its stack (usually a function-local variable in a C program). The ulimit is a system setting that prevents processes from using a large amount of memory for stack space. On the CLN or other server, especially one without swap space, that limit could help to prevent a greedy user process from consuming the RAM that the system needs to perform well. The setting is a trade off. By removing the limit, you give processes greater freedom while losing the stability that the limit can provide. In the end, user processes can usually perform a denial of service attack somehow on the local host, whether it's with the notorious "fork bomb" or some more insidious exploitation of a weakness in the kernel. Still, multi-level security is a good policy. > I've been instructed to file a bug report on openafs-bugs, and to debian > regarding the package, as the /etc/init.d/openafs-filserver script has > to be modified to do ulimit -s unlimited at each startup, as the setting > is a per-session thing. Speculation as to the cause is welcome. A per-session setting sounds like a good solution. > Please don't think a small thing of this. I've spent well over 40 > hours, along with the help of several people to weed this out! Yes, it sounds like it was quite a lot of work. I'm glad that the OpenAFS developers were so helpful and responsive, and I hope that your solution will be found by others in the mailing list archives. Congrats on recruiting allies and tracking it down! -- Ed L Cashin <[EMAIL PROTECTED]> _______________________________________________ OpenAFS-info mailing list [email protected] https://lists.openafs.org/mailman/listinfo/openafs-info
