=============================
WARNING: suspicious RCU usage
6.16.0-rc5-syzkaller-00121-gbc9ff192a6c9 #0 Not tainted
-----------------------------
net/core/netclassid_cgroup.c:23 suspicious rcu_dereference_check() usage!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 1
1 lock held by syz.8.1164/7745:
 #0: ffff8000872c0ea0 (rcu_read_lock_trace){....}-{0:0}, at: rcu_read_lock_trace include/linux/rcupdate_trace.h:53 [inline]
 #0: ffff8000872c0ea0 (rcu_read_lock_trace){....}-{0:0}, at: bpf_prog_test_run_syscall+0x224/0x7f0 net/bpf/test_run.c:1563

stack backtrace:
CPU: 0 UID: 0 PID: 7745 Comm: syz.8.1164 Not tainted 6.16.0-rc5-syzkaller-00121-gbc9ff192a6c9 #0 PREEMPT 
Hardware name: linux,dummy-virt (DT)
Call trace:
 show_stack+0x18/0x24 arch/arm64/kernel/stacktrace.c:466 (C)
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0xdc/0xf4 lib/dump_stack.c:120
 dump_stack+0x1c/0x28 lib/dump_stack.c:129
 lockdep_rcu_suspicious+0x174/0x2a8 kernel/locking/lockdep.c:6871
 task_cls_state+0x108/0x124 net/core/netclassid_cgroup.c:23
 __task_get_classid include/net/cls_cgroup.h:50 [inline]
 ____bpf_get_cgroup_classid_curr net/core/filter.c:3088 [inline]
 bpf_get_cgroup_classid_curr+0x18/0x5c net/core/filter.c:3086
 bpf_prog_841aec7193f618b3+0x30/0x50
 bpf_dispatcher_nop_func include/linux/bpf.h:1322 [inline]
 __bpf_prog_run include/linux/filter.h:709 [inline]
 bpf_prog_run include/linux/filter.h:725 [inline]
 bpf_prog_run_pin_on_cpu include/linux/filter.h:742 [inline]
 bpf_prog_test_run_syscall+0x4ac/0x7f0 net/bpf/test_run.c:1564
 bpf_prog_test_run kernel/bpf/syscall.c:4429 [inline]
 __sys_bpf+0xd78/0x25ac kernel/bpf/syscall.c:5854
 __do_sys_bpf kernel/bpf/syscall.c:5943 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5941 [inline]
 __arm64_sys_bpf+0x70/0xa4 kernel/bpf/syscall.c:5941
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x6c/0x258 arch/arm64/kernel/syscall.c:49
 el0_svc_common.constprop.0+0xac/0x230 arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x40/0x58 arch/arm64/kernel/syscall.c:151
 el0_svc+0x50/0x198 arch/arm64/kernel/entry-common.c:767
 el0t_64_sync_handler+0x10c/0x138 arch/arm64/kernel/entry-common.c:786
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600