Subj : js_Mark - segmentation fault
To   : netscape.public.mozilla.jseng
From : celleris@naver.com (Youngsun Jeong)
Date : Mon Sep 29 2003 05:57 am

Hello! I made a ECMAScript engine using spidermonkey, it has
additional js function like "setInterval" that was not implemented in
spidermonkey. There are some problems. See following backtrace;

backtrace:

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 16387 (LWP 23961)]
js_Mark (cx=0x8240a48, obj=0x8244ac0, arg=0x0) at jsobj.c:4134
4134            if (clasp->mark)
(gdb) where
#0  js_Mark (cx=0x8240a48, obj=0x8244ac0, arg=0x0) at jsobj.c:4134
#1  0x081283c3 in js_MarkGCThing (cx=0x8240a48, thing=0x8244ac0,
arg=0x0) at jsgc.c:879
#2  0x081283af in js_MarkGCThing (cx=0x8240a48,
thing=0x824d9e0,arg=0x8240a48) at jsgc.c:890
#3  0x081283af in js_MarkGCThing (cx=0x8240a48, thing=0x824b1e0,
arg=0x8240a48) at jsgc.c:890
#4  0x081283af in js_MarkGCThing (cx=0x8240a48, thing=0x82495e4,
arg=0x8240a48) at jsgc.c:890
#5  0x081283af in js_MarkGCThing (cx=0x8240a48, thing=0x8252410,
arg=0x8240a48) at jsgc.c:890
#6  0x081282c0 in gc_mark_atom_key_thing (thing=0x8245420,
arg=0x8240a48) at jsgc.c:783
#7  0x0811a53f in js_atom_marker (he=0x0, i=29, arg=0xbf5ff2a8) at
jsatom.c:383
#8  0x081290a4 in JS_HashTableEnumerateEntries (ht=0x8240bc0,
f=0x811a4f8 <js_atom_marker>, arg=0xbf5ff2a8)
    at jshash.c:365
#9  0x0811a57b in js_MarkAtomState (state=0x50, gcflags=80, mark=0x50,
data=0x50) at jsatom.c:399
#10 0x08128502 in js_GC (cx=0x8240a48, gcflags=5) at jsgc.c:1161
#11 0x081280dc in js_AllocGCThing (cx=0x8240a48, flags=3) at
jsgc.c:523
#12 0x0814cfb4 in js_NewString (cx=0x0, chars=0x0, length=17,
gcflag=0) at jsstr.c:2448
#13 0x08149f0d in js_ConcatStrings (cx=0x8240a48, left=0x8245448,
right=0x89ad200) at jsstr.c:177
#14 0x0812c54d in js_Interpret (cx=0x8240a48, result=0xbf5ff690) at
jsinterp.c:2303
#15 0x08129e4c in js_Execute (cx=0x8240a48, chain=0x8245470,
script=0x0, down=0xbf5ff8f0, special=0,
    result=0xbf5ff690) at jsinterp.c:1054
#16 0x08135c3c in obj_setInterval (cx=0x8240a48, obj=0x8244a70,
argc=2, argv=0x8254c54, rval=0xbf5ff690)
    at jsobj.c:1526
#17 0x0812996c in js_Invoke (cx=0x8240a48, argc=2, flags=0) at
jsinterp.c:843
#18 0x08131f64 in js_Interpret (cx=0x8240a48, result=0xbf5ff8ec) at
jsinterp.c:2854
#19 0x08129ac2 in js_Invoke (cx=0x8240a48, argc=1, flags=2) at
jsinterp.c:860
#20 0x08129c5e in js_InternalInvoke (cx=0x8240a48, obj=0x0, fval=0,
flags=2, argc=1, argv=0xbf5ffa70, rval=0x0)
    at jsinterp.c:935
#21 0x08117892 in JS_CallFunctionName (cx=0x8240a48, obj=0x8244a70,
name=0x818537c "Move", argc=1,
    argv=0xbf5ffa70, rval=0xbf5ffa74) at jsapi.c:3563
#22 0x080a8f11 in MonkeyMain::monkeyMain(char const*, DOM_Node*, char
const*) (
    script=0x8225ea8 "\n\t\n\tvar target;\n\tvar targetElement;\n\tvar
targetElement2;\n\t\n\tvar rad = 0;\n\tvar cx = 347;\n\tvar cy =
200;\n\tvar o
#23 0x080b48da in startScriptThread(void*) (arg=0x0) at Player.cpp:94
#24 0x40029442 in pthread_start_thread () from /lib/libpthread.so.0
#25 0x400294b1 in pthread_start_thread_event () from
/lib/libpthread.so.0

additional comment : This segmentation fault appears after 3 minutes.I
implement "setInterval" and add it to JSFunctionSpec of "Object Class"
in "jsobj.c" .

I printed "clasp->mark" then "cannot access memmory at 0x90" was
printed..
Is it GC problem? Thank you for any assistance.

.