git: vm: use normal COW inheritance for user-wired mappings

[Aaron LI]

commit 8c75d90806bd7438c2dfc9acfd99992966419b1a
Author: David Bidner <david at crap.solutions>
Date:   Sat Oct 3 16:55:50 2026 +0200

    vm: use normal COW inheritance for user-wired mappings
    
    Forking an mlock()ed MAP_PRIVATE file mapping can panic with
    "vm_fault_copy_wired: page missing". The wired-copy path expects the
    page in the front object, but it may be in a backing object or have
    been removed after the file was truncated.
    
    Use normal COW inheritance for normal mappings with only a user wire.
    The parent stays user-wired and the child remains unwired. The normal
    fault path resolves backing pages and handles pager errors. Keep eager
    copying for hard-wired and virtual-page-table mappings.
    
    Reviewed-by: dillon
    Bug: https://bugs.dragonflybsd.org/issues/3433

Summary of changes:
 sys/vm/vm_map.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

http://gitweb.dragonflybsd.org/dragonfly.git/commitdiff/8c75d90806bd7438c2dfc9acfd99992966419b1a


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