segfault in Parrot_string_mark

[coke]

With parrot r40897 and partcl r658;

running parrot tcl.pbc t_tcl/obj.test (need to run "make t_tcl" first to checkout the test files),

Looks like a loop:

#0  0xb7e4087c in Parrot_String_mark (interp=0x804f040, pmc=0xb6e4c248)    at ./src/pmc/string.c:540
#1  0xb7d43a7a in mark_special (interp=0x804f040, obj=0xb6e4c248)    at src/gc/mark_sweep.c:472
#2  0xb7d42aa7 in Parrot_gc_mark_PObj_alive (interp=0x804f040, obj=0x804f148)    at src/gc/api.c:230
#3  0xb7e67ee5 in Parrot_FixedPMCArray_mark (interp=0x804f040, pmc=0xb6e4abe0)    at ./src/pmc/fixedpmcarray.pmc:786
#4  0xb7d43a7a in mark_special (interp=0x804f040, obj=0xb6e4abe0)    at src/gc/mark_sweep.c:472
#5  0xb7d42aa7 in Parrot_gc_mark_PObj_alive (interp=0x804f040, obj=0x804f148)    at src/gc/api.c:230
#6  0xb7e67ee5 in Parrot_FixedPMCArray_mark (interp=0x804f040, pmc=0xb6e4ac28)    at ./src/pmc/fixedpmcarray.pmc:786
#7  0xb7d43a7a in mark_special (interp=0x804f040, obj=0xb6e4ac28)    at src/gc/mark_sweep.c:472
#8  0xb7d42aa7 in Parrot_gc_mark_PObj_alive (interp=0x804f040, obj=0x804f148)    at src/gc/api.c:230
#9  0xb7e830ac in Parrot_Object_mark (interp=0x804f040, pmc=0xb6e4ac40)    at ./src/pmc/object.pmc:196
#10 0xb7d43a7a in mark_special (interp=0x804f040, obj=0xb6e4ac40)    at src/gc/mark_sweep.c:472
#11 0xb7d42aa7 in Parrot_gc_mark_PObj_alive (interp=0x804f040, obj=0x804f148)    at src/gc/api.c:230
#12 0xb7e67ee5 in Parrot_FixedPMCArray_mark (interp=0x804f040, pmc=0xb6e49338)    at ./src/pmc/fixedpmcarray.pmc:786
#13 0xb7d43a7a in mark_special (interp=0x804f040, obj=0xb6e49338)    at src/gc/mark_sweep.c:472
#14 0xb7d42aa7 in Parrot_gc_mark_PObj_alive (interp=0x804f040, obj=0x804f148)    at src/gc/api.c:230
#15 0xb7e67ee5 in Parrot_FixedPMCArray_mark (interp=0x804f040, pmc=0xb6e49380)    at ./src/pmc/fixedpmcarray.pmc:786
#16 0xb7d43a7a in mark_special (interp=0x804f040, obj=0xb6e49380)    at src/gc/mark_sweep.c:472
#17 0xb7d42aa7 in Parrot_gc_mark_PObj_alive (interp=0x804f040, obj=0x804f148)    at src/gc/api.c:230
#18 0xb7e830ac in Parrot_Object_mark (interp=0x804f040, pmc=0xb6e49398)    at ./src/pmc/object.pmc:196
#19 0xb7d43a7a in mark_special (interp=0x804f040, obj=0xb6e49398)    at src/gc/mark_sweep.c:472
#20 0xb7d42aa7 in Parrot_gc_mark_PObj_alive (interp=0x804f040, obj=0x804f148)
#21 0xb7e67ee5 in Parrot_FixedPMCArray_mark (interp=0x804f040, pmc=0xb6e47ac0)    at ./src/pmc/fixedpmcarray.pmc:786
#22 0xb7d43a7a in mark_special (interp=0x804f040, obj=0xb6e47ac0)    at src/gc/mark_sweep.c:472
#23 0xb7d42aa7 in Parrot_gc_mark_PObj_alive (interp=0x804f040, obj=0x804f148)    at src/gc/api.c:230
#24 0xb7e67ee5 in Parrot_FixedPMCArray_mark (interp=0x804f040, pmc=0xb6e47b20)    at ./src/pmc/fixedpmcarray.pmc:786
#25 0xb7d43a7a in mark_special (interp=0x804f040, obj=0xb6e47b20)    at src/gc/mark_sweep.c:472
#26 0xb7d42aa7 in Parrot_gc_mark_PObj_alive (interp=0x804f040, obj=0x804f148)    at src/gc/api.c:230
#27 0xb7e830ac in Parrot_Object_mark (interp=0x804f040, pmc=0xb6e47b38)    at ./src/pmc/object.pmc:196
#28 0xb7d43a7a in mark_special (interp=0x804f040, obj=0xb6e47b38)    at src/gc/mark_sweep.c:472
#29 0xb7d42aa7 in Parrot_gc_mark_PObj_alive (interp=0x804f040, obj=0x804f148)    at src/gc/api.c:230
#30 0xb7e67ee5 in Parrot_FixedPMCArray_mark (interp=0x804f040, pmc=0xb6e461d0)    at ./src/pmc/fixedpmcarray.pmc:786
#31 0xb7d43a7a in mark_special (interp=0x804f040, obj=0xb6e461d0)    at src/gc/mark_sweep.c:472
#32 0xb7d42aa7 in Parrot_gc_mark_PObj_alive (interp=0x804f040, obj=0x804f148)    at src/gc/api.c:230
#33 0xb7e67ee5 in Parrot_FixedPMCArray_mark (interp=0x804f040, pmc=0xb6e46218)    at ./src/pmc/fixedpmcarray.pmc:786
#34 0xb7d43a7a in mark_special (interp=0x804f040, obj=0xb6e46218)    at src/gc/mark_sweep.c:472
#35 0xb7d42aa7 in Parrot_gc_mark_PObj_alive (interp=0x804f040, obj=0x804f148)    at src/gc/api.c:230
#36 0xb7e830ac in Parrot_Object_mark (interp=0x804f040, pmc=0xb6e46230)    at ./src/pmc/object.pmc:196
#37 0xb7d43a7a in mark_special (interp=0x804f040, obj=0xb6e46230)    at src/gc/mark_sweep.c:472
#38 0xb7d42aa7 in Parrot_gc_mark_PObj_alive (interp=0x804f040, obj=0x804f148)    at src/gc/api.c:230
#39 0xb7e67ee5 in Parrot_FixedPMCArray_mark (interp=0x804f040, pmc=0xb6e44790)    at ./src/pmc/fixedpmcarray.pmc:786
#40 0xb7d43a7a in mark_special (interp=0x804f040, obj=0xb6e44790)    at src/gc/mark_sweep.c:472
#41 0xb7d42aa7 in Parrot_gc_mark_PObj_alive (interp=0x804f040, obj=0x804f148)    at src/gc/api.c:230
#42 0xb7e67ee5 in Parrot_FixedPMCArray_mark (interp=0x804f040, pmc=0xb6e447f0)    at ./src/pmc/fixedpmcarray.pmc:786
#43 0xb7d43a7a in mark_special (interp=0x804f040, obj=0xb6e447f0)    at src/gc/mark_sweep.c:472
#44 0xb7d42aa7 in Parrot_gc_mark_PObj_alive (interp=0x804f040, obj=0x804f148)    at src/gc/api.c:230
#45 0xb7e830ac in Parrot_Object_mark (interp=0x804f040, pmc=0xb6e44808)    at ./src/pmc/object.pmc:196
#46 0xb7d43a7a in mark_special (interp=0x804f040, obj=0xb6e44808)    at src/gc/mark_sweep.c:472
#47 0xb7d42aa7 in Parrot_gc_mark_PObj_alive (interp=0x804f040, obj=0x804f148)    at src/gc/api.c:230
#48 0xb7e67ee5 in Parrot_FixedPMCArray_mark (interp=0x804f040, pmc=0xb6e430f8)    at ./src/pmc/fixedpmcarray.pmc:786
#49 0xb7d43a7a in mark_special (interp=0x804f040, obj=0xb6e430f8)    at src/gc/mark_sweep.c:472
#50 0xb7d42aa7 in Parrot_gc_mark_PObj_alive (interp=0x804f040, obj=0x804f148)    at src/gc/api.c:230
#51 0xb7e67ee5 in Parrot_FixedPMCArray_mark (interp=0x804f040, pmc=0xb6e43140)    at ./src/pmc/fixedpmcarray.pmc:786
#52 0xb7d43a7a in mark_special (interp=0x804f040, obj=0xb6e43140)    at src/gc/mark_sweep.c:472
#53 0xb7d42aa7 in Parrot_gc_mark_PObj_alive (interp=0x804f040, obj=0x804f148)    at src/gc/api.c:230
#54 0xb7e830ac in Parrot_Object_mark (interp=0x804f040, pmc=0xb6e43158)    at ./src/pmc/object.pmc:196
#55 0xb7d43a7a in mark_special (interp=0x804f040, obj=0xb6e43158)    at src/gc/mark_sweep.c:472
#56 0xb7d42aa7 in Parrot_gc_mark_PObj_alive (interp=0x804f040, obj=0x804f148)    at src/gc/api.c:230
#57 0xb7e67ee5 in Parrot_FixedPMCArray_mark (interp=0x804f040, pmc=0xb6e418e0)    at ./src/pmc/fixedpmcarray.pmc:786
#58 0xb7d43a7a in mark_special (interp=0x804f040, obj=0xb6e418e0)    at src/gc/mark_sweep.c:472
#59 0xb7d42aa7 in Parrot_gc_mark_PObj_alive (interp=0x804f040, obj=0x804f148)    at src/gc/api.c:230
#60 0xb7e67ee5 in Parrot_FixedPMCArray_mark (interp=0x804f040, pmc=0xb6e41988)    at ./src/pmc/fixedpmcarray.pmc:786
#61 0xb7d43a7a in mark_special (interp=0x804f040, obj=0xb6e41988)
.... <SNIP>