XEmacs livelocks

Starting from 21.4.3 XEmacs was sort of livelocking (process is running, but X events just disappear into ether) on Irix 6.5. First it was every few weeks, but recently, i.e. 21.4.8 and 21.4.9, I've been hitting it pretty reliably several times a day, usually if I'm doing something related to the reading from a file or a pipe. So I've decided to dig a bit to see what's going on. The symptoms are that all of a sudden all frames would stop responding to X events. If there was a TTY frame, it would not respond to keyboard as well. dbx was always showing that the process is in select, so I was blaming select, or rather stuffed fdset, for my problems. After some more investigation, I found that actually select works just fine (I can intercept select from libc on Irix since it's a weak symbol), its the XEmacs, which is doing something funny. To reproduce the problem, I wrote a bit of lisp which calls Darrel's xcscope in a tight loop (setq l '("Select" "nohide_traverse" "vnode_t" "exportinto" "mountinfo")) (interactive (list(cscope-prompt-for-symbol "Find"))) (while t (let ((ll l)) (while ll (setq b (current-buffer)) (setq symbol (car ll)) (cscope-call (format "Finding symbol: %s" symbol) (list "-1" symbol)) (set-buffer b) (setq ll (cdr ll))))) By evaluating that, I can get to a livelock on an X display in a matter of minutes (sometimes seconds, depending how lucky I am). Yet at the same time my select intercept still runs and if I move mouse over blanked frame, click on the frame or expose it, I'm getting the event, select returns and comes back for the next event. Nothing like this happens on the TTY run, which suggests that there is a memory corruption somewhere in the X layer. There is a secondary proof of this theory of memory curruption in X - I cannot start XEmacs on X if I compile with GNU malloc, compiling with standard malloc would allow the X sessiont to start. Since I know next to nothing about XEmacs core, I need guidance in tracking it down: I can help, test, make suggestions etc in whatever form I can. max