Commit e5e890630533 for kernel

commit e5e890630533bdc15b26a34bb8e7ef539bdf1322
Author: Fernando Fernandez Mancera <fmancera@suse.de>
Date:   Wed Mar 4 13:03:56 2026 +0100

    net: bridge: fix nd_tbl NULL dereference when IPv6 is disabled

    When booting with the 'ipv6.disable=1' parameter, the nd_tbl is never
    initialized because inet6_init() exits before ndisc_init() is called
    which initializes it. Then, if neigh_suppress is enabled and an ICMPv6
    Neighbor Discovery packet reaches the bridge, br_do_suppress_nd() will
    dereference ipv6_stub->nd_tbl which is NULL, passing it to
    neigh_lookup(). This causes a kernel NULL pointer dereference.

     BUG: kernel NULL pointer dereference, address: 0000000000000268
     Oops: 0000 [#1] PREEMPT SMP NOPTI
     [...]
     RIP: 0010:neigh_lookup+0x16/0xe0
     [...]
     Call Trace:
      <IRQ>
      ? neigh_lookup+0x16/0xe0
      br_do_suppress_nd+0x160/0x290 [bridge]
      br_handle_frame_finish+0x500/0x620 [bridge]
      br_handle_frame+0x353/0x440 [bridge]
      __netif_receive_skb_core.constprop.0+0x298/0x1110
      __netif_receive_skb_one_core+0x3d/0xa0
      process_backlog+0xa0/0x140
      __napi_poll+0x2c/0x170
      net_rx_action+0x2c4/0x3a0
      handle_softirqs+0xd0/0x270
      do_softirq+0x3f/0x60

    Fix this by replacing IS_ENABLED(IPV6) call with ipv6_mod_enabled() in
    the callers. This is in essence disabling NS/NA suppression when IPv6 is
    disabled.

    Fixes: ed842faeb2bd ("bridge: suppress nd pkts on BR_NEIGH_SUPPRESS ports")
    Reported-by: Guruprasad C P <gurucp2005@gmail.com>
    Closes: https://lore.kernel.org/netdev/CAHXs0ORzd62QOG-Fttqa2Cx_A_VFp=utE2H2VTX5nqfgs7LDxQ@mail.gmail.com/
    Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>
    Reviewed-by: Ido Schimmel <idosch@nvidia.com>
    Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
    Link: https://patch.msgid.link/20260304120357.9778-1-fmancera@suse.de
    Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/bridge/br_device.c b/net/bridge/br_device.c
index ee01122f466f..f7502e62dd35 100644
--- a/net/bridge/br_device.c
+++ b/net/bridge/br_device.c
@@ -74,7 +74,7 @@ netdev_tx_t br_dev_xmit(struct sk_buff *skb, struct net_device *dev)
 	     eth_hdr(skb)->h_proto == htons(ETH_P_RARP)) &&
 	    br_opt_get(br, BROPT_NEIGH_SUPPRESS_ENABLED)) {
 		br_do_proxy_suppress_arp(skb, br, vid, NULL);
-	} else if (IS_ENABLED(CONFIG_IPV6) &&
+	} else if (ipv6_mod_enabled() &&
 		   skb->protocol == htons(ETH_P_IPV6) &&
 		   br_opt_get(br, BROPT_NEIGH_SUPPRESS_ENABLED) &&
 		   pskb_may_pull(skb, sizeof(struct ipv6hdr) +
diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
index 1405f1061a54..2cbae0f9ae1f 100644
--- a/net/bridge/br_input.c
+++ b/net/bridge/br_input.c
@@ -170,7 +170,7 @@ int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb
 	    (skb->protocol == htons(ETH_P_ARP) ||
 	     skb->protocol == htons(ETH_P_RARP))) {
 		br_do_proxy_suppress_arp(skb, br, vid, p);
-	} else if (IS_ENABLED(CONFIG_IPV6) &&
+	} else if (ipv6_mod_enabled() &&
 		   skb->protocol == htons(ETH_P_IPV6) &&
 		   br_opt_get(br, BROPT_NEIGH_SUPPRESS_ENABLED) &&
 		   pskb_may_pull(skb, sizeof(struct ipv6hdr) +