From 77a71ef2b76c2e858c81e10349f28534307f1c91 Mon Sep 17 00:00:00 2001
From: Qi Wang <interwq@gwu.edu>
Date: Wed, 6 Jun 2018 15:52:52 -0700
Subject: [PATCH] Fall back to the default pthread_create if RTLD_NEXT fails.

---
 .../internal/background_thread_externs.h         |  1 -
 src/background_thread.c                          | 16 +++++++++-------
 src/ctl.c                                        | 14 --------------
 3 files changed, 9 insertions(+), 22 deletions(-)

diff --git a/include/jemalloc/internal/background_thread_externs.h b/include/jemalloc/internal/background_thread_externs.h
index 3209aa49..0f997e18 100644
--- a/include/jemalloc/internal/background_thread_externs.h
+++ b/include/jemalloc/internal/background_thread_externs.h
@@ -8,7 +8,6 @@ extern atomic_b_t background_thread_enabled_state;
 extern size_t n_background_threads;
 extern size_t max_background_threads;
 extern background_thread_info_t *background_thread_info;
-extern bool can_enable_background_thread;
 
 bool background_thread_create(tsd_t *tsd, unsigned arena_ind);
 bool background_threads_enable(tsd_t *tsd);
diff --git a/src/background_thread.c b/src/background_thread.c
index 3517a3bb..4613537c 100644
--- a/src/background_thread.c
+++ b/src/background_thread.c
@@ -22,9 +22,6 @@ size_t max_background_threads;
 /* Thread info per-index. */
 background_thread_info_t *background_thread_info;
 
-/* False if no necessary runtime support. */
-bool can_enable_background_thread;
-
 /******************************************************************************/
 
 #ifdef JEMALLOC_PTHREAD_CREATE_WRAPPER
@@ -812,16 +809,21 @@ pthread_create_fptr_init(void) {
 	if (pthread_create_fptr != NULL) {
 		return false;
 	}
+	/*
+	 * Try the next symbol first, because 1) when use lazy_lock we have a
+	 * wrapper for pthread_create; and 2) application may define its own
+	 * wrapper as well (and can call malloc within the wrapper).
+	 */
 	pthread_create_fptr = dlsym(RTLD_NEXT, "pthread_create");
 	if (pthread_create_fptr == NULL) {
-		can_enable_background_thread = false;
-		if (config_lazy_lock || opt_background_thread) {
+		if (config_lazy_lock) {
 			malloc_write("<jemalloc>: Error in dlsym(RTLD_NEXT, "
 			    "\"pthread_create\")\n");
 			abort();
+		} else {
+			/* Fall back to the default symbol. */
+			pthread_create_fptr = pthread_create;
 		}
-	} else {
-		can_enable_background_thread = true;
 	}
 
 	return false;
diff --git a/src/ctl.c b/src/ctl.c
index ef3eca4d..9ea2bb30 100644
--- a/src/ctl.c
+++ b/src/ctl.c
@@ -1556,13 +1556,6 @@ background_thread_ctl(tsd_t *tsd, const size_t *mib, size_t miblen,
 
 		background_thread_enabled_set(tsd_tsdn(tsd), newval);
 		if (newval) {
-			if (!can_enable_background_thread) {
-				malloc_printf("<jemalloc>: Error in dlsym("
-			            "RTLD_NEXT, \"pthread_create\"). Cannot "
-				    "enable background_thread\n");
-				ret = EFAULT;
-				goto label_return;
-			}
 			if (background_threads_enable(tsd)) {
 				ret = EFAULT;
 				goto label_return;
@@ -1617,13 +1610,6 @@ max_background_threads_ctl(tsd_t *tsd, const size_t *mib, size_t miblen,
 		}
 
 		if (background_thread_enabled()) {
-			if (!can_enable_background_thread) {
-				malloc_printf("<jemalloc>: Error in dlsym("
-			            "RTLD_NEXT, \"pthread_create\"). Cannot "
-				    "enable background_thread\n");
-				ret = EFAULT;
-				goto label_return;
-			}
 			background_thread_enabled_set(tsd_tsdn(tsd), false);
 			if (background_threads_disable(tsd)) {
 				ret = EFAULT;