nicholas clark suqhccl4org wed nov 07 2007 082332am 0800 jerry hedden wrote given following code attached usrbinperl use strict use warnings warnings redefine isa universalisa universalisa sub printjumping original isan comment goto isa main obj bless someclass printuniversalisaobj undef ok ok n 5100 produces jumping original isa segmentation fault core dumped 19376 jumping original isa 19376 invalid read size 4 19376 0x8171f56 s_varname svc11808 19376 0x81729f6 s_find_uninit_var svc11915 19376 0x81742cb s_find_uninit_var svc12135 19376 0x817436e perl_report_uninit svc12165 19376 0x8137887 perl_sv_2pv_flags svc2754 19376 0x824b8b5 xs_universal_isa universalc310 19376 0x81c80c8 perl_pp_goto pp_ctlc2403 19376 0x80c5e73 perl_runops_debug dumpc1931 19376 0x81039ee s_run_body perlc2384 19376 0x8102e53 perl_run perlc2302 19376 0x80606a1 main perlmainc113 19376 address 0x0 stackd mallocd recently freed else cv const cv find_runcvnull sv sv av av cv cvpadlistcv return null av avav_fetchcvpadlistcv 0 false sv av_fetchav targ false sv_setpvnname svpv_nolen_constsv svcursv line 11808 sv av_fetchav targ false assume returning null dont want blindly patch first time returned null b previous av_fetch checked c correct response getting null segv dont know unitialised warning nicholas clark thu 07 aug 2008 172055 0000 perl 47233 core dump caused goto