diff --git a/sys/amd64/linux/linux_sysvec.c b/sys/amd64/linux/linux_sysvec.c
--- a/sys/amd64/linux/linux_sysvec.c
+++ b/sys/amd64/linux/linux_sysvec.c
@@ -804,6 +804,10 @@
 	return (error);
 }
 
+/*
+ * linux_vdso_install() and linux_exec_sysvec_init() must be called
+ * after exec_sysvec_init() which is SI_SUB_EXEC (SI_ORDER_ANY).
+ */
 static void
 linux_exec_sysvec_init(void *param)
 {
@@ -826,7 +830,7 @@
 	if (bootverbose)
 		printf("Linux x86-64 vDSO tsc_selector: %lu\n", *ktsc_selector);
 }
-SYSINIT(elf_linux_exec_sysvec_init, SI_SUB_EXEC, SI_ORDER_ANY,
+SYSINIT(elf_linux_exec_sysvec_init, SI_SUB_EXEC + 1, SI_ORDER_ANY,
     linux_exec_sysvec_init, &elf_linux_sysvec);
 
 static void
@@ -850,7 +854,7 @@
 
 	linux_vdso_reloc(linux_vdso_mapping, linux_vdso_base);
 }
-SYSINIT(elf_linux_vdso_init, SI_SUB_EXEC, SI_ORDER_FIRST,
+SYSINIT(elf_linux_vdso_init, SI_SUB_EXEC + 1, SI_ORDER_FIRST,
     linux_vdso_install, NULL);
 
 static void
diff --git a/sys/amd64/linux32/linux32_sysvec.c b/sys/amd64/linux32/linux32_sysvec.c
--- a/sys/amd64/linux32/linux32_sysvec.c
+++ b/sys/amd64/linux32/linux32_sysvec.c
@@ -970,6 +970,10 @@
 	return (error);
 }
 
+/*
+ * linux_vdso_install() and linux_exec_sysvec_init() must be called
+ * after exec_sysvec_init() which is SI_SUB_EXEC (SI_ORDER_ANY).
+ */
 static void
 linux_exec_sysvec_init(void *param)
 {
@@ -991,7 +995,7 @@
 	if (bootverbose)
 		printf("Linux i386 vDSO tsc_selector: %u\n", *ktsc_selector);
 }
-SYSINIT(elf_linux_exec_sysvec_init, SI_SUB_EXEC, SI_ORDER_ANY,
+SYSINIT(elf_linux_exec_sysvec_init, SI_SUB_EXEC + 1, SI_ORDER_ANY,
     linux_exec_sysvec_init, &elf_linux_sysvec);
 
 static void
@@ -1013,7 +1017,7 @@
 
 	linux_vdso_reloc(linux_vdso_mapping, linux_vdso_base);
 }
-SYSINIT(elf_linux_vdso_init, SI_SUB_EXEC, SI_ORDER_FIRST,
+SYSINIT(elf_linux_vdso_init, SI_SUB_EXEC + 1, SI_ORDER_FIRST,
     linux_vdso_install, NULL);
 
 static void
diff --git a/sys/arm64/linux/linux_sysvec.c b/sys/arm64/linux/linux_sysvec.c
--- a/sys/arm64/linux/linux_sysvec.c
+++ b/sys/arm64/linux/linux_sysvec.c
@@ -476,6 +476,10 @@
 	return (error);
 }
 
+/*
+ * linux_vdso_install() and linux_exec_sysvec_init() must be called
+ * after exec_sysvec_init() which is SI_SUB_EXEC (SI_ORDER_ANY).
+ */
 static void
 linux_exec_sysvec_init(void *param)
 {
@@ -491,7 +495,7 @@
 	ktimekeep_base = (l_uintptr_t *)(linux_vdso_mapping + tkoff);
 	*ktimekeep_base = sv->sv_timekeep_base;
 }
-SYSINIT(elf_linux_exec_sysvec_init, SI_SUB_EXEC, SI_ORDER_ANY,
+SYSINIT(elf_linux_exec_sysvec_init, SI_SUB_EXEC + 1, SI_ORDER_ANY,
     linux_exec_sysvec_init, &elf_linux_sysvec);
 
 static void
@@ -513,7 +517,7 @@
 
 	linux_vdso_reloc(linux_vdso_mapping, linux_vdso_base);
 }
-SYSINIT(elf_linux_vdso_init, SI_SUB_EXEC, SI_ORDER_FIRST,
+SYSINIT(elf_linux_vdso_init, SI_SUB_EXEC + 1, SI_ORDER_FIRST,
     linux_vdso_install, NULL);
 
 static void
diff --git a/sys/i386/linux/linux_sysvec.c b/sys/i386/linux/linux_sysvec.c
--- a/sys/i386/linux/linux_sysvec.c
+++ b/sys/i386/linux/linux_sysvec.c
@@ -915,6 +915,10 @@
 	return (error);
 }
 
+/*
+ * linux_vdso_install() and linux_exec_sysvec_init() must be called
+ * after exec_sysvec_init() which is SI_SUB_EXEC (SI_ORDER_ANY).
+ */
 static void
 linux_exec_sysvec_init(void *param)
 {
@@ -936,7 +940,7 @@
 	if (bootverbose)
 		printf("Linux i386 vDSO tsc_selector: %u\n", *ktsc_selector);
 }
-SYSINIT(elf_linux_exec_sysvec_init, SI_SUB_EXEC, SI_ORDER_ANY,
+SYSINIT(elf_linux_exec_sysvec_init, SI_SUB_EXEC + 1, SI_ORDER_ANY,
     linux_exec_sysvec_init, &elf_linux_sysvec);
 
 static void
@@ -958,7 +962,7 @@
 
 	linux_vdso_reloc(linux_vdso_mapping, linux_vdso_base);
 }
-SYSINIT(elf_linux_vdso_init, SI_SUB_EXEC, SI_ORDER_FIRST,
+SYSINIT(elf_linux_vdso_init, SI_SUB_EXEC + 1, SI_ORDER_FIRST,
     linux_vdso_install, NULL);
 
 static void
@@ -1169,3 +1173,8 @@
 
 DECLARE_MODULE_TIED(linuxelf, linux_elf_mod, SI_SUB_EXEC, SI_ORDER_ANY);
 FEATURE(linux, "Linux 32bit support");
+
+/*
+ * linux_vdso_install() and linux_exec_sysvec_init() must be called
+ * after exec_sysvec_init() which is SI_SUB_EXEC (SI_ORDER_ANY).
+ */