diff --git a/include/jemalloc/internal/arena_externs.h b/include/jemalloc/internal/arena_externs.h
index 36d91869..2df55184 100644
--- a/include/jemalloc/internal/arena_externs.h
+++ b/include/jemalloc/internal/arena_externs.h
@@ -82,6 +82,9 @@ void	arena_prefork0(tsdn_t *tsdn, arena_t *arena);
 void	arena_prefork1(tsdn_t *tsdn, arena_t *arena);
 void	arena_prefork2(tsdn_t *tsdn, arena_t *arena);
 void	arena_prefork3(tsdn_t *tsdn, arena_t *arena);
+void	arena_prefork4(tsdn_t *tsdn, arena_t *arena);
+void	arena_prefork5(tsdn_t *tsdn, arena_t *arena);
+void	arena_prefork6(tsdn_t *tsdn, arena_t *arena);
 void	arena_postfork_parent(tsdn_t *tsdn, arena_t *arena);
 void	arena_postfork_child(tsdn_t *tsdn, arena_t *arena);
 
diff --git a/include/jemalloc/internal/private_symbols.txt b/include/jemalloc/internal/private_symbols.txt
index 30cd3958..64bea334 100644
--- a/include/jemalloc/internal/private_symbols.txt
+++ b/include/jemalloc/internal/private_symbols.txt
@@ -51,6 +51,9 @@ arena_prefork0
 arena_prefork1
 arena_prefork2
 arena_prefork3
+arena_prefork4
+arena_prefork5
+arena_prefork6
 arena_prof_accum
 arena_prof_promote
 arena_prof_tctx_get
diff --git a/src/arena.c b/src/arena.c
index cef61cc3..43bad81c 100644
--- a/src/arena.c
+++ b/src/arena.c
@@ -1743,29 +1743,39 @@ arena_boot(void) {
 void
 arena_prefork0(tsdn_t *tsdn, arena_t *arena) {
 	malloc_mutex_prefork(tsdn, &arena->decay.mtx);
+}
+
+void
+arena_prefork1(tsdn_t *tsdn, arena_t *arena) {
 	if (config_stats && config_tcache) {
 		malloc_mutex_prefork(tsdn, &arena->tcache_ql_mtx);
 	}
 }
 
 void
-arena_prefork1(tsdn_t *tsdn, arena_t *arena) {
+arena_prefork2(tsdn_t *tsdn, arena_t *arena) {
 	extents_prefork(tsdn, &arena->extents_cached);
 	extents_prefork(tsdn, &arena->extents_retained);
 }
 
 void
-arena_prefork2(tsdn_t *tsdn, arena_t *arena) {
+arena_prefork3(tsdn_t *tsdn, arena_t *arena) {
 	malloc_mutex_prefork(tsdn, &arena->extent_freelist_mtx);
 }
 
 void
-arena_prefork3(tsdn_t *tsdn, arena_t *arena) {
-	unsigned i;
-
+arena_prefork4(tsdn_t *tsdn, arena_t *arena) {
 	base_prefork(tsdn, arena->base);
+}
+
+void
+arena_prefork5(tsdn_t *tsdn, arena_t *arena) {
 	malloc_mutex_prefork(tsdn, &arena->large_mtx);
-	for (i = 0; i < NBINS; i++) {
+}
+
+void
+arena_prefork6(tsdn_t *tsdn, arena_t *arena) {
+	for (unsigned i = 0; i < NBINS; i++) {
 		malloc_mutex_prefork(tsdn, &arena->bins[i].lock);
 	}
 }
diff --git a/src/jemalloc.c b/src/jemalloc.c
index b5379cc4..ecfecf9c 100644
--- a/src/jemalloc.c
+++ b/src/jemalloc.c
@@ -2773,7 +2773,8 @@ _malloc_prefork(void)
 	tcache_prefork(tsd_tsdn(tsd));
 	malloc_mutex_prefork(tsd_tsdn(tsd), &arenas_lock);
 	prof_prefork0(tsd_tsdn(tsd));
-	for (i = 0; i < 3; i++) {
+	/* Break arena prefork into stages to preserve lock order. */
+	for (i = 0; i < 7; i++) {
 		for (j = 0; j < narenas; j++) {
 			if ((arena = arena_get(tsd_tsdn(tsd), j, false)) !=
 			    NULL) {
@@ -2787,16 +2788,23 @@ _malloc_prefork(void)
 				case 2:
 					arena_prefork2(tsd_tsdn(tsd), arena);
 					break;
+				case 3:
+					arena_prefork3(tsd_tsdn(tsd), arena);
+					break;
+				case 4:
+					arena_prefork4(tsd_tsdn(tsd), arena);
+					break;
+				case 5:
+					arena_prefork5(tsd_tsdn(tsd), arena);
+					break;
+				case 6:
+					arena_prefork6(tsd_tsdn(tsd), arena);
+					break;
 				default: not_reached();
 				}
 			}
 		}
 	}
-	for (i = 0; i < narenas; i++) {
-		if ((arena = arena_get(tsd_tsdn(tsd), i, false)) != NULL) {
-			arena_prefork3(tsd_tsdn(tsd), arena);
-		}
-	}
 	prof_prefork1(tsd_tsdn(tsd));
 }
 
diff --git a/test/unit/fork.c b/test/unit/fork.c
index 96b1c5a0..afe22141 100644
--- a/test/unit/fork.c
+++ b/test/unit/fork.c
@@ -9,6 +9,19 @@ TEST_BEGIN(test_fork) {
 	void *p;
 	pid_t pid;
 
+	/* Set up a manually managed arena for test. */
+	unsigned arena_ind;
+	size_t sz = sizeof(unsigned);
+	assert_d_eq(mallctl("arenas.create", (void *)&arena_ind, &sz, NULL, 0),
+	    0, "Unexpected mallctl() failure");
+
+	/* Migrate to the new arena. */
+	unsigned old_arena_ind;
+	sz = sizeof(old_arena_ind);
+	assert_d_eq(mallctl("thread.arena", (void *)&old_arena_ind, &sz,
+	    (void *)&arena_ind, sizeof(arena_ind)), 0,
+	    "Unexpected mallctl() failure");
+
 	p = malloc(1);
 	assert_ptr_not_null(p, "Unexpected malloc() failure");