Re-initialize logmsgs mutex upon logger initialization to prevent lock errors

Similar to the patch that moved the fork earlier in the startup sequence to
prevent mutex errors in the recursive mutex surrounding the read/write thread
registration lock, this patch re-initializes the logmsgs mutex.  Part of the
start up sequence before forking the process into the background includes
reading asterisk.conf; this has to occur prior to the call to daemon in order
to read startup parameters.  When reading in a conf file, log statements can
be generated.  Since this can't be avoided, the mutex instead is
re-initialized to ensure a reset of any thread tracking information.

This patch also includes some additional debugging to catch errors when
locking or unlocking the recursive mutex that surrounds locks when the
DEBUG_THREADS build option is enabled.  DO_CRASH or THREAD_CRASH will
cause an abort() if a mutex error is detected.

(issue ASTERISK-19463)
Reported by: mjordan
Tesetd by: mjordan

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.8@376586 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/include/asterisk/lock.h b/include/asterisk/lock.h
index fbcbecccf916a04db3037745af2fd3bad8cb9eda..61b84d1a9d0fe0866cc0f17014adcfd1d7761571 100644 (file)
--- a/include/asterisk/lock.h
+++ b/include/asterisk/lock.h
@@ -428,12 +428,24 @@ int ast_find_lock_info(void *lock_addr, char *filename, size_t filename_size, in
 
 static inline void ast_reentrancy_lock(struct ast_lock_track *lt)
 {
-       pthread_mutex_lock(&lt->reentr_mutex);
+       int res;
+       if ((res = pthread_mutex_lock(&lt->reentr_mutex))) {
+               fprintf(stderr, "ast_reentrancy_lock failed: '%s' (%d)\n", strerror(res), res);
+#if defined(DO_CRASH) || defined(THREAD_CRASH)
+               abort();
+#endif
+       }
 }
 
 static inline void ast_reentrancy_unlock(struct ast_lock_track *lt)
 {
-       pthread_mutex_unlock(&lt->reentr_mutex);
+       int res;
+       if ((res = pthread_mutex_unlock(&lt->reentr_mutex))) {
+               fprintf(stderr, "ast_reentrancy_unlock failed: '%s' (%d)\n", strerror(res), res);
+#if defined(DO_CRASH) || defined(THREAD_CRASH)
+               abort();
+#endif
+       }
 }
 
 static inline void ast_reentrancy_init(struct ast_lock_track **plt)

diff --git a/main/lock.c b/main/lock.c
index c48c71e7c95601a4b1ba29c3a7e074613f4feb9c..dedbf79cb748b11f963a5c0715c033c56284167b 100644 (file)
--- a/main/lock.c
+++ b/main/lock.c
@@ -51,8 +51,8 @@ int __ast_pthread_mutex_init(int tracking, const char *filename, int lineno, con
        int res;
        pthread_mutexattr_t  attr;
 
-       t->track = NULL;
 #ifdef DEBUG_THREADS
+       t->track = NULL;
 #if defined(AST_MUTEX_INIT_W_CONSTRUCTORS) && defined(CAN_COMPARE_MUTEX_TO_INIT_VALUE)
        if ((t->mutex) != ((pthread_mutex_t) PTHREAD_MUTEX_INITIALIZER)) {
 /*

diff --git a/main/logger.c b/main/logger.c
index 4076cb17955c7b28b3ef33746a94c70d7d7a2692..deb4ca0d3fa77112c15c9c6aff6c14c89b303622 100644 (file)
--- a/main/logger.c
+++ b/main/logger.c
@@ -1133,8 +1133,17 @@ int init_logger(void)
        /* auto rotate if sig SIGXFSZ comes a-knockin */
        sigaction(SIGXFSZ, &handle_SIGXFSZ, NULL);
 
-       /* start logger thread */
+       /* Re-initialize the logmsgs mutex.  The recursive mutex can be accessed prior
+        * to Asterisk being forked into the background, which can cause the thread
+        * ID tracked by the underlying pthread mutex to be different than the ID of
+        * the thread that unlocks the mutex.  Since init_logger is called after the
+        * fork, it is safe to initialize the mutex here for future accesses.
+        */
+       ast_mutex_destroy(&logmsgs.lock);
+       ast_mutex_init(&logmsgs.lock);
        ast_cond_init(&logcond, NULL);
+
+       /* start logger thread */
        if (ast_pthread_create(&logthread, NULL, logger_thread, NULL) < 0) {
                ast_cond_destroy(&logcond);
                return -1;