From: kn <kn@openbsd.org>
Date: Fri, 11 Feb 2022 12:06:48 +0000 (+0000)
Subject: Backout previous "Unwire with map lock held" (commitid: eQBvWUwShD91dN9Z)
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=2e08805ee98ba8b859cb3470d90ae96370d0c081;p=openbsd

Backout previous "Unwire with map lock held" (commitid: eQBvWUwShD91dN9Z)

WITNESS builds broke^W^Wkernels panic on boot as reported by anton and bluhm.
Booting bsd.mp in single-user mode inside VMM shows:

root on sd0a (5f9e458ed30b39ab.a) swap on sd0b dump on sd0b
Enter pathname of shell or RETURN for sh:
witness: lock order reversal:
 1st 0xfffffd801f8ce468 vmmaplk (&map->lock)
 2nd 0xfffffd801b8162c0 inode (&ip->i_lock)
lock order "&ip->i_lock"(rrwlock) -> "&map->lock"(rwlock) first seen at:
#0  rw_enter_read+0x38
#1  uvmfault_lookup+0x8a
#2  uvm_fault_check+0x32
#3  uvm_fault+0xfb
#4  kpageflttrap+0x12c
#5  kerntrap+0x91
#6  alltraps_kern_meltdown+0x7b
#7  copyout+0x53
#8  ffs_read+0x1f6
#9  VOP_READ+0x41
#10 vn_rdwr+0xa1
#11 vmcmd_map_readvn+0xa0
#12 exec_process_vmcmds+0x88
#13 sys_execve+0x732
#14 start_init+0x26f
#15 proc_trampoline+0x1c
lock order data w1 -> w2 missing
# exit
kernel: protection fault trap, code=0
Stopped at      witness_checkorder+0x312:       movl    0x10(%r14),%ecx

gkoehler reported faults on poisened addresses on macppc dual G5.
---

diff --git a/sys/uvm/uvm_map.c b/sys/uvm/uvm_map.c
index ff4689214d5..9263c4d8ab5 100644
--- a/sys/uvm/uvm_map.c
+++ b/sys/uvm/uvm_map.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uvm_map.c,v 1.285 2022/02/11 09:25:04 kn Exp $	*/
+/*	$OpenBSD: uvm_map.c,v 1.286 2022/02/11 12:06:48 kn Exp $	*/
 /*	$NetBSD: uvm_map.c,v 1.86 2000/11/27 08:40:03 chs Exp $	*/
 
 /*
@@ -2734,7 +2734,6 @@ 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);