netdev - [PATCH net] bonding: provide a net pointer to __skb_flow

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Message-ID: <20260120161744.1893263-1-edumazet@google.com>
Date: Tue, 20 Jan 2026 16:17:44 +0000
From: Eric Dumazet <edumazet@...gle.com>
To: "David S . Miller" <davem@...emloft.net>, Jakub Kicinski <kuba@...nel.org>, 
	Paolo Abeni <pabeni@...hat.com>
Cc: Simon Horman <horms@...nel.org>, netdev@...r.kernel.org, eric.dumazet@...il.com, 
	Eric Dumazet <edumazet@...gle.com>, syzbot+c46409299c70a221415e@...kaller.appspotmail.com, 
	Matteo Croce <mcroce@...hat.com>, Stanislav Fomichev <sdf@...ichev.me>
Subject: [PATCH net] bonding: provide a net pointer to __skb_flow_dissect()

After 3cbf4ffba5ee ("net: plumb network namespace into __skb_flow_dissect")
we have to provide a net pointer to __skb_flow_dissect(),
either via skb->dev, skb->sk, or a user provided pointer.

In the following case, syzbot was able to cook a bare skb.

WARNING: net/core/flow_dissector.c:1131 at __skb_flow_dissect+0xb57/0x68b0 net/core/flow_dissector.c:1131, CPU#1: syz.2.1418/11053
Call Trace:
 <TASK>
  bond_flow_dissect drivers/net/bonding/bond_main.c:4093 [inline]
  __bond_xmit_hash+0x2d7/0xba0 drivers/net/bonding/bond_main.c:4157
  bond_xmit_hash_xdp drivers/net/bonding/bond_main.c:4208 [inline]
  bond_xdp_xmit_3ad_xor_slave_get drivers/net/bonding/bond_main.c:5139 [inline]
  bond_xdp_get_xmit_slave+0x1fd/0x710 drivers/net/bonding/bond_main.c:5515
  xdp_master_redirect+0x13f/0x2c0 net/core/filter.c:4388
  bpf_prog_run_xdp include/net/xdp.h:700 [inline]
  bpf_test_run+0x6b2/0x7d0 net/bpf/test_run.c:421
  bpf_prog_test_run_xdp+0x795/0x10e0 net/bpf/test_run.c:1390
  bpf_prog_test_run+0x2c7/0x340 kernel/bpf/syscall.c:4703
  __sys_bpf+0x562/0x860 kernel/bpf/syscall.c:6182
  __do_sys_bpf kernel/bpf/syscall.c:6274 [inline]
  __se_sys_bpf kernel/bpf/syscall.c:6272 [inline]
  __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:6272
  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
  do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94

Fixes: 58deb77cc52d ("bonding: balance ICMP echoes in layer3+4 mode")
Reported-by: syzbot+c46409299c70a221415e@...kaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/696faa23.050a0220.4cb9c.001f.GAE@google.com/T/#u
Signed-off-by: Eric Dumazet <edumazet@...gle.com>
Cc: Matteo Croce <mcroce@...hat.com>
Cc: Stanislav Fomichev <sdf@...ichev.me>
---
 drivers/net/bonding/bond_main.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 0aca6c937297def91d5740dfd456800432b5e343..e7caf400a59cbd9680adea3d1b8ab7a22c78f7e6 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -4096,8 +4096,9 @@ static bool bond_flow_dissect(struct bonding *bond, struct sk_buff *skb, const v
 	case BOND_XMIT_POLICY_ENCAP23:
 	case BOND_XMIT_POLICY_ENCAP34:
 		memset(fk, 0, sizeof(*fk));
-		return __skb_flow_dissect(NULL, skb, &flow_keys_bonding,
-					  fk, data, l2_proto, nhoff, hlen, 0);
+		return __skb_flow_dissect(dev_net(bond->dev), skb,
+					  &flow_keys_bonding, fk, data,
+					  l2_proto, nhoff, hlen, 0);
 	default:
 		break;
 	}
-- 
2.52.0.457.g6b5491de43-goog