On Tue, Jul 7, 2026 at 6:35 PM Vadim Fedorenko
[off-list ref] wrote:

On 07/07/2026 02:06, zhangzl2013@126.com wrote:

quoted

From: Zhaolong Zhang <redacted>

When booting with the 'ipv6.disable=1' parameter, the devconf_all is
never initialized because inet6_init() exits before addrconf_init() is
called which initializes it. bond_send_validate(), however, will still
call bond_ns_send_all() even ipv6 is indeed disabled. It will lead to
NULL derefence of net->ipv6.devconf_all in ip6_pol_route().

  BUG: kernel NULL pointer dereference, address: 000000000000000c
  [...]
  Workqueue: bond0 bond_arp_monitor [bonding]
  RIP: 0010:ip6_pol_route+0x69/0x480
  [...]
  Call Trace:
   <TASK>
   ? srso_return_thunk+0x5/0x5f
   ? __pfx_ip6_pol_route_output+0x10/0x10
   fib6_rule_lookup+0xfe/0x260
   ? wakeup_preempt+0x8a/0x90
   ? srso_return_thunk+0x5/0x5f
   ? srso_return_thunk+0x5/0x5f
   ? sched_balance_rq+0x369/0x810
   ip6_route_output_flags+0xd7/0x170
   bond_ns_send_all+0xde/0x280 [bonding]
   bond_ab_arp_probe+0x296/0x320 [bonding]
   ? srso_return_thunk+0x5/0x5f
   bond_activebackup_arp_mon+0xb4/0x2c0 [bonding]
   process_one_work+0x196/0x370
   worker_thread+0x1af/0x320
   ? srso_return_thunk+0x5/0x5f
   ? __pfx_worker_thread+0x10/0x10
   kthread+0xe3/0x120
   ? __pfx_kthread+0x10/0x10
   ret_from_fork+0x199/0x260
   ? __pfx_kthread+0x10/0x10
   ret_from_fork_asm+0x1a/0x30
   </TASK>

Fix this by adding ipv6_mod_enabled() condition check in the caller.

Fixes: 4e24be018eb9 ("bonding: add new parameter ns_targets")
Signed-off-by: Qianheng Peng <redacted>
Signed-off-by: Zhaolong Zhang <redacted>
---
  drivers/net/bonding/bond_main.c | 3 ++-
  1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index e044fc733b8c..522eab060f9e 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c

@@ -3455,7 +3455,8 @@ static void bond_send_validate(struct bonding *bond, struct slave *slave)
  {
      bond_arp_send_all(bond, slave);
  #if IS_ENABLED(CONFIG_IPV6)
-     bond_ns_send_all(bond, slave);
+     if (likely(ipv6_mod_enabled()))
+             bond_ns_send_all(bond, slave);
  #endif
  }

ipv6_mod_enabled() doesn't depend on CONFIG_IPV6, please, remove
#if IS_ENABLED as well

No, bond_ns_send_all() is static and protected by IS_ENABLED(CONFIG_IPV6).
Remove this IS_ENABLED will cause build error.

Thanks
Hangbin