From: Elise Huard Date: 2011-04-29T04:52:32+09:00 Subject: [ruby-core:35940] [Ruby 1.9 - Bug #4630][Open] PROCDEBUG to non-zero values causes segmentation faults in check_env in trunk Issue #4630 has been reported by Elise Huard. ---------------------------------------- Bug #4630: PROCDEBUG to non-zero values causes segmentation faults in check_env in trunk http://redmine.ruby-lang.org/issues/4630 Author: Elise Huard Status: Open Priority: Normal Assignee: Category: Target version: ruby -v: 1.9.3dev PROCDEBUG is meant to show debugging output from the vm. However, when it's activated in vm.c #define PROCDEBUG 1 The make process fails in segmentation faults. I've narrowed it down to the following variables displayed in check_env: env->block.dfp[3] and env->block.dfp[4] Commenting them out like so makes the segfaults disappear. static int check_env(rb_env_t * const env) { printf("---\n"); printf("envptr: %p\n", (void *)&env->block.dfp[0]); printf("orphan: %p\n", (void *)env->block.dfp[1]); printf("inheap: %p\n", (void *)env->block.dfp[2]); /* printf("envval: %10p ", (void *)env->block.dfp[3]); dp(env->block.dfp[3]); printf("penvv : %10p ", (void *)env->block.dfp[4]); dp(env->block.dfp[4]); */ printf("lfp: %10p\n", (void *)env->block.lfp); printf("dfp: %10p\n", (void *)env->block.dfp); /* if (env->block.dfp[4]) { printf(">>\n"); check_env_value(env->block.dfp[4]); printf("<<\n"); } */ return 1; } However, I'm not clued up enough on the inner workings of the VM to say why or how that should be fixed intelligently. -- http://redmine.ruby-lang.org