=============================
WARNING: suspicious RCU usage
syzkaller #0 Not tainted
-----------------------------
net/netfilter/nf_conntrack_netlink.c:3389 suspicious rcu_dereference_check() usage!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 1
2 locks held by syz.0.17/4461:
 #0: ffff80001ca2a418 (nfnl_subsys_ctnetlink_exp){+.+.}-{3:3}, at: nfnl_lock net/netfilter/nfnetlink.c:98 [inline]
 #0: ffff80001ca2a418 (nfnl_subsys_ctnetlink_exp){+.+.}-{3:3}, at: nfnetlink_rcv_msg+0x888/0xf88 net/netfilter/nfnetlink.c:295
 #1: ffff8000153a4898 (nf_conntrack_expect_lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
 #1: ffff8000153a4898 (nf_conntrack_expect_lock){+...}-{2:2}, at: nf_ct_expect_iterate_net+0x48/0x260 net/netfilter/nf_conntrack_expect.c:569

stack backtrace:
CPU: 1 PID: 4461 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/14/2026
Call trace:
 dump_backtrace+0x1c4/0x1f0 arch/arm64/kernel/stacktrace.c:158
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
 __dump_stack+0x30/0x40 lib/dump_stack.c:88
 dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106
 dump_stack+0x1c/0x5c lib/dump_stack.c:113
 lockdep_rcu_suspicious+0x20c/0x3cc kernel/locking/lockdep.c:6627
 expect_iter_name+0x128/0x12c net/netfilter/nf_conntrack_netlink.c:3389
 nf_ct_expect_iterate_net+0x104/0x260 net/netfilter/nf_conntrack_expect.c:579
 ctnetlink_del_expect+0x400/0x59c net/netfilter/nf_conntrack_netlink.c:-1
 nfnetlink_rcv_msg+0xaac/0xf88 net/netfilter/nfnetlink.c:302
 netlink_rcv_skb+0x220/0x3ec net/netlink/af_netlink.c:2516
 nfnetlink_rcv+0x210/0x1c54 net/netfilter/nfnetlink.c:659
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x5fc/0x80c net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x6f0/0x9d8 net/netlink/af_netlink.c:1877
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 ____sys_sendmsg+0x588/0x90c net/socket.c:2519
 ___sys_sendmsg net/socket.c:2573 [inline]
 __sys_sendmsg+0x288/0x374 net/socket.c:2602
 __do_sys_sendmsg net/socket.c:2611 [inline]
 __se_sys_sendmsg net/socket.c:2609 [inline]
 __arm64_sys_sendmsg+0x80/0x94 net/socket.c:2609
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585