syzbot

=============================
WARNING: suspicious RCU usage
6.9.0-syzkaller-12171-gccf23c916ca3 #0 Not tainted
-----------------------------
net/netfilter/nfnetlink_queue.c:261 suspicious rcu_dereference_check() usage!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 1
2 locks held by ksoftirqd/1/24:
 #0: ffffffff8e333f20 (rcu_callback){....}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
 #0: ffffffff8e333f20 (rcu_callback){....}-{0:0}, at: rcu_do_batch kernel/rcu/tree.c:2529 [inline]
 #0: ffffffff8e333f20 (rcu_callback){....}-{0:0}, at: rcu_core+0xa86/0x1830 kernel/rcu/tree.c:2809
 #1: ffff888023e42858 (&inst->lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
 #1: ffff888023e42858 (&inst->lock){+.-.}-{2:2}, at: nfqnl_flush net/netfilter/nfnetlink_queue.c:405 [inline]
 #1: ffff888023e42858 (&inst->lock){+.-.}-{2:2}, at: instance_destroy_rcu+0x30/0x220 net/netfilter/nfnetlink_queue.c:172

stack backtrace:
CPU: 1 PID: 24 Comm: ksoftirqd/1 Not tainted 6.9.0-syzkaller-12171-gccf23c916ca3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
 lockdep_rcu_suspicious+0x221/0x340 kernel/locking/lockdep.c:6712
 nf_reinject net/netfilter/nfnetlink_queue.c:323 [inline]
 nfqnl_reinject+0x6ec/0x1120 net/netfilter/nfnetlink_queue.c:397
 nfqnl_flush net/netfilter/nfnetlink_queue.c:410 [inline]
 instance_destroy_rcu+0x1ae/0x220 net/netfilter/nfnetlink_queue.c:172
 rcu_do_batch kernel/rcu/tree.c:2535 [inline]
 rcu_core+0xafd/0x1830 kernel/rcu/tree.c:2809
 handle_softirqs+0x2c4/0x970 kernel/softirq.c:554
 run_ksoftirqd+0xca/0x130 kernel/softirq.c:928
 smpboot_thread_fn+0x544/0xa30 kernel/smpboot.c:164
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>