diff --git a/include/jemalloc/internal/extent_externs.h b/include/jemalloc/internal/extent_externs.h
index acb3ef49..489a813c 100644
--- a/include/jemalloc/internal/extent_externs.h
+++ b/include/jemalloc/internal/extent_externs.h
@@ -15,7 +15,8 @@ extent_t *extent_alloc(tsdn_t *tsdn, arena_t *arena);
 void extent_dalloc(tsdn_t *tsdn, arena_t *arena, extent_t *extent);
 
 extent_hooks_t *extent_hooks_get(arena_t *arena);
-extent_hooks_t *extent_hooks_set(arena_t *arena, extent_hooks_t *extent_hooks);
+extent_hooks_t *extent_hooks_set(tsd_t *tsd, arena_t *arena,
+    extent_hooks_t *extent_hooks);
 
 #ifdef JEMALLOC_JET
 size_t extent_size_quantize_floor(size_t size);
diff --git a/src/ctl.c b/src/ctl.c
index c3514bdd..2c3f9945 100644
--- a/src/ctl.c
+++ b/src/ctl.c
@@ -2154,7 +2154,7 @@ arena_i_extent_hooks_ctl(tsd_t *tsd, const size_t *mib, size_t miblen,
 			extent_hooks_t *new_extent_hooks
 			    JEMALLOC_CC_SILENCE_INIT(NULL);
 			WRITE(new_extent_hooks, extent_hooks_t *);
-			old_extent_hooks = extent_hooks_set(arena,
+			old_extent_hooks = extent_hooks_set(tsd, arena,
 			    new_extent_hooks);
 			READ(old_extent_hooks, extent_hooks_t *);
 		} else {
diff --git a/src/extent.c b/src/extent.c
index fb7a1468..e95858e3 100644
--- a/src/extent.c
+++ b/src/extent.c
@@ -197,8 +197,18 @@ extent_hooks_get(arena_t *arena) {
 }
 
 extent_hooks_t *
-extent_hooks_set(arena_t *arena, extent_hooks_t *extent_hooks) {
-	return base_extent_hooks_set(arena->base, extent_hooks);
+extent_hooks_set(tsd_t *tsd, arena_t *arena, extent_hooks_t *extent_hooks) {
+	background_thread_info_t *info;
+	if (have_background_thread) {
+		info = arena_background_thread_info_get(arena);
+		malloc_mutex_lock(tsd_tsdn(tsd), &info->mtx);
+	}
+	extent_hooks_t *ret = base_extent_hooks_set(arena->base, extent_hooks);
+	if (have_background_thread) {
+		malloc_mutex_unlock(tsd_tsdn(tsd), &info->mtx);
+	}
+
+	return ret;
 }
 
 static void