diff --git a/ChangeLog b/ChangeLog
index c4c3ba393c..561445045e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,4 +1,8 @@
-Wed Oct 13 22:53:19 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+Wed Oct 13 23:07:19 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* iseq.c (insn_operand_intern, rb_iseq_disasm): fix format specifiers.
+
+	* vm.c (thread_free): ditto.
 
 	* numeric.c (check_uint): get rid of overflow on LLP64 platforms.
 
diff --git a/iseq.c b/iseq.c
index a0d600033f..617165e08b 100644
--- a/iseq.c
+++ b/iseq.c
@@ -739,11 +739,11 @@ insn_operand_intern(rb_iseq_t *iseq,
 
     switch (type) {
       case TS_OFFSET:		/* LONG */
-	ret = rb_sprintf("%ld", pos + len + op);
+	ret = rb_sprintf("%"PRIdSIZE, pos + len + op);
 	break;
 
       case TS_NUM:		/* ULONG */
-	ret = rb_sprintf("%lu", op);
+	ret = rb_sprintf("%"PRIuVALUE, op);
 	break;
 
       case TS_LINDEX:
@@ -985,7 +985,7 @@ rb_iseq_disasm(VALUE self)
 		int argc = iseqdat->argc;
 		int opts = iseqdat->arg_opts;
 		if (i >= argc && i < argc + opts - 1) {
-		    snprintf(opti, sizeof(opti), "Opt=%ld",
+		    snprintf(opti, sizeof(opti), "Opt=%"PRIdVALUE,
 			     iseqdat->arg_opt_table[i - argc]);
 		}
 	    }
diff --git a/vm.c b/vm.c
index 6fb6cd12c8..084c30964a 100644
--- a/vm.c
+++ b/vm.c
@@ -1699,7 +1699,7 @@ thread_free(void *ptr)
 	}
 
 	if (th->locking_mutex != Qfalse) {
-	    rb_bug("thread_free: locking_mutex must be NULL (%p:%ld)", (void *)th, th->locking_mutex);
+	    rb_bug("thread_free: locking_mutex must be NULL (%p:%p)", (void *)th, (void *)th->locking_mutex);
 	}
 	if (th->keeping_mutexes != NULL) {
 	    rb_bug("thread_free: keeping_mutexes must be NULL (%p:%p)", (void *)th, (void *)th->keeping_mutexes);