Hackers, I've managed to find more details concerning GC failure on AMD64. The heap node that causes GC to crash is allocated on modules loading: #0 cinfo_alloc (size=2, name=0x58a3e0 ":", number=1, flags=0, obj=0x58a360) at info.c:24 #1 0x0000000000403b0f in mod_loadCon (mod=0x52ccf0, name=0x58a3e0 ":", obj=0x58a360) at module.c:463 #2 0x0000000000403ccd in mod_loadObject (mod=0x52ccf0, offs=36277, obj=0x58a360) at module.c:516 #3 0x0000000000402a13 in mod_resolve (module=0x58a380 "Prelude", item=0x58a3a0 ":") at module.c:209 #4 0x0000000000402f0d in mod_loadConstTable (mod=0x588ea0, finfo=0x58a218) at module.c:322 #5 0x0000000000403a4b in mod_loadFun (mod=0x588ea0, name=0x58a1e0 "valid", obj=0x58a160) at module.c:439 #6 0x0000000000403cb4 in mod_loadObject (mod=0x588ea0, offs=1475, obj=0x58a160) at module.c:514 #7 0x0000000000402a13 in mod_resolve (module=0x58a180 "Main", item=0x58a1a0 "valid") at module.c:209 #8 0x0000000000402f0d in mod_loadConstTable (mod=0x588ea0, finfo=0x58a0f0) at module.c:322 #9 0x0000000000403a4b in mod_loadFun (mod=0x588ea0, name=0x58a0c0 "queens", obj=0x58a040) at module.c:439 #10 0x0000000000403cb4 in mod_loadObject (mod=0x588ea0, offs=1580, obj=0x58a040) at module.c:514 #11 0x0000000000402a13 in mod_resolve (module=0x58a060 "Main", item=0x58a080 "queens") at module.c:209 #12 0x0000000000402f0d in mod_loadConstTable (mod=0x588ea0, finfo=0x589fa8) at module.c:322 #13 0x0000000000403a4b in mod_loadFun (mod=0x588ea0, name=0x589f80 "main", obj=0x589f40) at module.c:439 #14 0x0000000000403cb4 in mod_loadObject (mod=0x588ea0, offs=1606, obj=0x589f40) at module.c:514 #15 0x0000000000402a13 in mod_resolve (module=0x7fffffea0b88 "Main", item=0x41f3f1 "main") at module.c:209 #16 0x00000000004046ee in initGlobals (mainMod=0x7fffffea0b88 "Main", mainFunc=0x7fffffea0248, _toplevel=0x7fffffea0250, _driver=0x7fffffea0240) at main.c:120 #17 0x0000000000404880 in init (mainMod=0x7fffffea0b88 "Main", mainFunc=0x7fffffea0248, _toplevel=0x7fffffea0250, _driver=0x7fffffea0240) at main.c:145 #18 0x00000000004048de in main (argc=4, argv=0x7fffffea0348) at main.c:171 The node represents the (:) constructor which takes 2 arguments (size = 2), but the space allocated is only 1 word (no args[]). Why? Next node which occupies the next word is treated as pointer to args by the GC which leads to crash. Thanks, Michal --------------------------------------------------------------------- Toshiba i FIFA World Cup Wygraj bilety i notebooki z Intel Centrino Duo Mobile Technology http://link.interia.pl/f1912