From dd39b6fd12717957dad02bc84e29286db8497cb4 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Mon, 14 Sep 2009 20:40:40 +0200
Subject: optionally raise trap when encountering inconsistency

---
 mutrace.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/mutrace.c b/mutrace.c
index a287541..0b0d147 100644
--- a/mutrace.c
+++ b/mutrace.c
@@ -19,9 +19,16 @@
 /* FIXMES:
  *
  *   - we probably should cover rwlocks, too
+ *   - and conds, too!
  *
  */
 
+#if defined(__i386__) || defined(__x86_64__)
+#define DEBUG_TRAP __asm__("int $3")
+#else
+#define DEBUG_TRAP raise(SIGTRAP)
+#endif
+
 typedef void (*fnptr_t)(void);
 
 struct mutex_info {
@@ -61,6 +68,8 @@ static unsigned show_n_owner_changed_min = 2;
 static unsigned show_n_contended_min = 0;
 static unsigned show_n_max = 10;
 
+static bool raise_trap = false;
+
 static int (*real_pthread_mutex_init)(pthread_mutex_t *mutex, const pthread_mutexattr_t *mutexattr) = NULL;
 static int (*real_pthread_mutex_destroy)(pthread_mutex_t *mutex) = NULL;
 static int (*real_pthread_mutex_lock)(pthread_mutex_t *mutex) = NULL;
@@ -609,6 +618,9 @@ static void mutex_lock(pthread_mutex_t *mutex, bool busy) {
         if (mi->n_lock_level > 0 && mi->type != PTHREAD_MUTEX_RECURSIVE) {
                 __sync_fetch_and_add(&n_broken, 1);
                 mi->broken = true;
+
+                if (raise_trap)
+                        DEBUG_TRAP;
         }
 
         mi->n_lock_level++;
@@ -695,6 +707,9 @@ static void mutex_unlock(pthread_mutex_t *mutex) {
         if (mi->n_lock_level <= 0) {
                 __sync_fetch_and_add(&n_broken, 1);
                 mi->broken = true;
+
+                if (raise_trap)
+                        DEBUG_TRAP;
         }
 
         mi->n_lock_level--;
-- 
cgit