Unwire with map lock held

uvm_unmap_remove() effectively requires its caller to lock the vm map.

Even though uvm_map_teardown() is only called after a map's last reference
is dropped and is thus safe from other threads accessing the map, grab the
map's lock in uvm_map_teardown() to satify upcoming lock assertions in
uvm_unmap_remove().

Tested as part of a larger diff through
- amd64 package bulk builds by naddy
- amd64, arm64, powerpc64 base builds and regress by bluhm
- amd64 and sparc64 base builds and regress by me

Feedback mpi
OK kettenis

1 files changed, 2 insertions, 1 deletions

diff --git a/sys/uvm/uvm_map.c b/sys/uvm/uvm_map.c
index c931418f753..f37e75d038d 100644
--- a/sys/uvm/uvm_map.c
+++ b/sys/uvm/uvm_map.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uvm_map.c,v 1.282 2021/12/21 22:21:32 mpi Exp $	*/
+/*	$OpenBSD: uvm_map.c,v 1.283 2022/02/10 10:14:02 kn Exp $	*/
 /*	$NetBSD: uvm_map.c,v 1.86 2000/11/27 08:40:03 chs Exp $	*/
 
 /*
@@ -2734,6 +2734,7 @@ uvm_map_teardown(struct vm_map *map)
 	KERNEL_ASSERT_UNLOCKED();
 
 	KASSERT((map->flags & VM_MAP_INTRSAFE) == 0);
+	vm_map_lock(map);
 
 	/* Remove address selectors. */
 	uvm_addr_destroy(map->uaddr_exe);