git: db6c7c7f8d87 - main - vmspace_fork(): do not override offset for the guard entries

[Konstantin Belousov]

The branch main has been updated by kib:

URL: 
https://cgit.FreeBSD.org/src/commit/?id=db6c7c7f8d870f377fcd1cc98e4832681bb5bdf0

commit db6c7c7f8d870f377fcd1cc98e4832681bb5bdf0
Author:     Konstantin Belousov <k...@freebsd.org>
AuthorDate: 2023-07-20 17:45:01 +0000
Commit:     Konstantin Belousov <k...@freebsd.org>
CommitDate: 2023-07-20 19:04:03 +0000

    vmspace_fork(): do not override offset for the guard entries
    
    The offset field contains protection for the stack guards.
    
    Reported by:    cy
    Fixes:  21e45c30c35c9aa732073f725924caf581c93460
    MFC after:      1 week
---
 sys/vm/vm_map.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/sys/vm/vm_map.c b/sys/vm/vm_map.c
index 997a49111a59..444e09986d4e 100644
--- a/sys/vm/vm_map.c
+++ b/sys/vm/vm_map.c
@@ -4181,7 +4181,8 @@ vm_map_copy_entry(
                            src_entry->start);
                } else {
                        dst_entry->object.vm_object = NULL;
-                       dst_entry->offset = 0;
+                       if ((dst_entry->eflags & MAP_ENTRY_GUARD) == 0)
+                               dst_entry->offset = 0;
                        if (src_entry->cred != NULL) {
                                dst_entry->cred = curthread->td_ucred;
                                crhold(dst_entry->cred);