# Fixes a memory leak in WASI builds of Ruby where VM jump buffers are sometimes not freed. --- a/cont.c +++ b/cont.c @@ -1518,6 +1518,51 @@ cont_restore_thread(rb_context_t *cont) rb_raise(rb_eRuntimeError, "can't call across trace_func"); } +#if defined(__wasm__) && !defined(__EMSCRIPTEN__) + if (th->ec->tag != sec->tag) { + /* find the lowest common ancestor tag of the current EC and the saved EC */ + + struct rb_vm_tag *lowest_common_ancestor = NULL; + size_t num_tags = 0; + size_t num_saved_tags = 0; + for (struct rb_vm_tag *tag = th->ec->tag; tag != NULL; tag = tag->prev) { + ++num_tags; + } + for (struct rb_vm_tag *tag = sec->tag; tag != NULL; tag = tag->prev) { + ++num_saved_tags; + } + + size_t min_tags = num_tags <= num_saved_tags ? num_tags : num_saved_tags; + + struct rb_vm_tag *tag = th->ec->tag; + while (num_tags > min_tags) { + tag = tag->prev; + --num_tags; + } + + struct rb_vm_tag *saved_tag = sec->tag; + while (num_saved_tags > min_tags) { + saved_tag = saved_tag->prev; + --num_saved_tags; + } + + while (min_tags > 0) { + if (tag == saved_tag) { + lowest_common_ancestor = tag; + break; + } + tag = tag->prev; + saved_tag = saved_tag->prev; + --min_tags; + } + + /* free all the jump buffers between the current EC's tag and the lowest common ancestor tag */ + for (struct rb_vm_tag *tag = th->ec->tag; tag != lowest_common_ancestor; tag = tag->prev) { + rb_vm_tag_jmpbuf_deinit(&tag->buf); + } + } +#endif + /* copy vm stack */ #ifdef CAPTURE_JUST_VALID_VM_STACK MEMCPY(th->ec->vm_stack, --- a/signal.c +++ b/signal.c @@ -849,6 +849,7 @@ check_stack_overflow(int sig, const uintptr_t addr, const ucontext_t *ctx) * otherwise it can cause stack overflow again at the same * place. */ if ((crit = (!ec->tag->prev || !--uplevel)) != FALSE) break; + rb_vm_tag_jmpbuf_deinit(&ec->tag->buf); ec->tag = ec->tag->prev; } reset_sigmask(sig); --- a/vm.c +++ b/vm.c @@ -2729,6 +2729,7 @@ vm_exec_handle_exception(rb_execution_context_t *ec, enum ruby_tag_type state, V if (VM_FRAME_FINISHED_P(ec->cfp)) { rb_vm_pop_frame(ec); ec->errinfo = (VALUE)err; + rb_vm_tag_jmpbuf_deinit(&ec->tag->buf); ec->tag = ec->tag->prev; EC_JUMP_TAG(ec, state); } --- a/vm_trace.c +++ b/vm_trace.c @@ -455,6 +455,7 @@ rb_exec_event_hooks(rb_trace_arg_t *trace_arg, rb_hook_list_t *hooks, int pop_p) if (state) { if (pop_p) { if (VM_FRAME_FINISHED_P(ec->cfp)) { + rb_vm_tag_jmpbuf_deinit(&ec->tag->buf); ec->tag = ec->tag->prev; } rb_vm_pop_frame(ec);