git: 2466a1871154 - stable/14 - ifnet: Initialize the address family dependent data region earlier

The branch stable/14 has been updated by zlei:

URL: https://cgit.FreeBSD.org/src/commit/?id=2466a18711548113d3ca4c61ccc7d6717adb6ade

commit 2466a18711548113d3ca4c61ccc7d6717adb6ade
Author:     Zhenlei Huang <zlei@FreeBSD.org>
AuthorDate: 2025-05-22 15:00:05 +0000
Commit:     Zhenlei Huang <zlei@FreeBSD.org>
CommitDate: 2025-07-07 10:03:58 +0000

    ifnet: Initialize the address family dependent data region earlier
    
    if_link_ifnet() adds the interface to the global network interface list,
    and it is a natural synchronization point. With this change, any threads
    that obtain the reference of the interface via ifunit(), ifunit_ref() etc.,
    will be guaranteed to see the address family dependent data rightly.
    
    The issue [1] reported by Mike Belanger also hints the potential race.
    
    MFC note: this change depends on e64fe5ad3a23, as calculating the max
    IPv6 MTU through all the interfaces requires the current interface to
    be added to the global network interface list firstly.
    
    [1] https://lists.freebsd.org/archives/freebsd-net/2025-May/006817.html
    
    Reviewed by:    glebius
    MFC after:      1 month
    MFC with:       e64fe5ad3a23 netinet6: Remove a set but not used global variable in6_maxmtu
    Differential Revision:  https://reviews.freebsd.org/D49358
    
    (cherry picked from commit 098b5d4dc744283a90b2d80c11395ecc18a84084)
---
 sys/net/if.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/sys/net/if.c b/sys/net/if.c
index b4ffa9883efc..a0570aed32e9 100644
--- a/sys/net/if.c
+++ b/sys/net/if.c
@@ -948,11 +948,11 @@ if_attach_internal(struct ifnet *ifp, bool vmove)
 	}
 #endif
 
-	if_link_ifnet(ifp);
-
 	if (domain_init_status >= 2)
 		if_attachdomain1(ifp);
 
+	if_link_ifnet(ifp);
+
 	EVENTHANDLER_INVOKE(ifnet_arrival_event, ifp);
 	if (IS_DEFAULT_VNET(curvnet))
 		devctl_notify("IFNET", ifp->if_xname, "ATTACH", NULL);