git: a6e48fe943dc - stable/13 - vm_map_growstack(): handle max protection for stacks

From: Konstantin Belousov <kib_at_FreeBSD.org>
Date: Fri, 25 Aug 2023 01:08:31 UTC
The branch stable/13 has been updated by kib:

URL: https://cgit.FreeBSD.org/src/commit/?id=a6e48fe943dc93b113564401bc22214419192386

commit a6e48fe943dc93b113564401bc22214419192386
Author:     Konstantin Belousov <kib@FreeBSD.org>
AuthorDate: 2023-07-25 13:56:29 +0000
Commit:     Konstantin Belousov <kib@FreeBSD.org>
CommitDate: 2023-08-25 01:06:44 +0000

    vm_map_growstack(): handle max protection for stacks
    
    (cherry picked from commit aa928a52164fe57965491d63e57de66e9c078e1a)
---
 sys/vm/vm_map.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/sys/vm/vm_map.c b/sys/vm/vm_map.c
index 9588f0591bcc..d4e4f2c89679 100644
--- a/sys/vm/vm_map.c
+++ b/sys/vm/vm_map.c
@@ -4606,7 +4606,7 @@ vm_map_stack_locked(vm_map_t map, vm_offset_t addrbos, vm_size_t max_ssize,
 		 * object offset.
 		 */
 		gap_entry->next_read = sgp;
-		gap_entry->offset = prot;
+		gap_entry->offset = prot | PROT_MAX(max);
 	} else {
 		(void)vm_map_delete(map, bot, top);
 	}
@@ -4626,7 +4626,7 @@ vm_map_growstack(vm_map_t map, vm_offset_t addr, vm_map_entry_t gap_entry)
 	struct ucred *cred;
 	vm_offset_t gap_end, gap_start, grow_start;
 	vm_size_t grow_amount, guard, max_grow;
-	vm_prot_t prot;
+	vm_prot_t prot, max;
 	rlim_t lmemlim, stacklim, vmemlim;
 	int rv, rv1;
 	bool gap_deleted, grow_down, is_procstack;
@@ -4771,7 +4771,8 @@ retry:
 		 * The gap_entry "offset" field is overloaded.  See
 		 * vm_map_stack_locked().
 		 */
-		prot = gap_entry->offset;
+		prot = PROT_EXTRACT(gap_entry->offset);
+		max = PROT_MAX_EXTRACT(gap_entry->offset);
 
 		grow_start = gap_entry->end - grow_amount;
 		if (gap_entry->start + grow_amount == gap_entry->end) {
@@ -4785,7 +4786,7 @@ retry:
 			gap_deleted = false;
 		}
 		rv = vm_map_insert(map, NULL, 0, grow_start,
-		    grow_start + grow_amount, prot, prot, MAP_STACK_GROWS_DOWN);
+		    grow_start + grow_amount, prot, max, MAP_STACK_GROWS_DOWN);
 		if (rv != KERN_SUCCESS) {
 			if (gap_deleted) {
 				rv1 = vm_map_insert(map, NULL, 0, gap_start,