git: f28d489aaaa4 - stable/13 - vm_map_protect(): move guard handling at the last phase into an empty dedicated helper

The branch stable/13 has been updated by kib:

URL: https://cgit.FreeBSD.org/src/commit/?id=f28d489aaaa417afe984a096dfbfecbfb6b2a695

commit f28d489aaaa417afe984a096dfbfecbfb6b2a695
Author:     Konstantin Belousov <kib@FreeBSD.org>
AuthorDate: 2023-07-28 00:14:07 +0000
Commit:     Konstantin Belousov <kib@FreeBSD.org>
CommitDate: 2023-08-25 01:06:44 +0000

    vm_map_protect(): move guard handling at the last phase into an empty dedicated helper
    
    (cherry picked from commit 79169929f04d00e51a901d1e4cb377d2475bf660)
---
 sys/vm/vm_map.c | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/sys/vm/vm_map.c b/sys/vm/vm_map.c
index d4e4f2c89679..d443c320b799 100644
--- a/sys/vm/vm_map.c
+++ b/sys/vm/vm_map.c
@@ -2716,6 +2716,13 @@ vm_map_pmap_enter(vm_map_t map, vm_offset_t addr, vm_prot_t prot,
 	VM_OBJECT_RUNLOCK(object);
 }
 
+static void
+vm_map_protect_guard(vm_map_entry_t entry, vm_prot_t new_prot,
+    vm_prot_t new_maxprot, int flags)
+{
+	MPASS((entry->eflags & MAP_ENTRY_GUARD) != 0);
+}
+
 /*
  *	vm_map_protect:
  *
@@ -2774,12 +2781,13 @@ again:
 		check_prot |= new_maxprot;
 	for (entry = first_entry; entry->start < end;
 	    entry = vm_map_entry_succ(entry)) {
-		if ((entry->eflags & MAP_ENTRY_GUARD) != 0)
-			continue;
 		if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0) {
 			vm_map_unlock(map);
 			return (KERN_INVALID_ARGUMENT);
 		}
+		if ((entry->eflags & MAP_ENTRY_GUARD) != 0) {
+			continue;
+		}
 		if (!CONTAINS_BITS(entry->max_protection, check_prot)) {
 			vm_map_unlock(map);
 			return (KERN_PROTECTION_FAILURE);
@@ -2879,10 +2887,15 @@ again:
 	    entry->start < end;
 	    vm_map_try_merge_entries(map, prev_entry, entry),
 	    prev_entry = entry, entry = vm_map_entry_succ(entry)) {
-		if (rv != KERN_SUCCESS ||
-		    (entry->eflags & MAP_ENTRY_GUARD) != 0)
+		if (rv != KERN_SUCCESS)
 			continue;
 
+		if ((entry->eflags & MAP_ENTRY_GUARD) != 0) {
+			vm_map_protect_guard(entry, new_prot, new_maxprot,
+			    flags);
+			continue;
+		}
+
 		old_prot = entry->protection;
 
 		if ((flags & VM_MAP_PROTECT_SET_MAXPROT) != 0) {