=============================
WARNING: suspicious RCU usage
6.16.0-rc7-syzkaller-g82af5ea7c611 #0 Not tainted
-----------------------------
net/core/netclassid_cgroup.c:24 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.3.129/7321:
 #0: ffff80008f869b60 (rcu_read_lock_trace){....}-{0:0}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:330

stack backtrace:
CPU: 0 UID: 0 PID: 7321 Comm: syz.3.129 Not tainted 6.16.0-rc7-syzkaller-g82af5ea7c611 #0 PREEMPT 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call trace:
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C)
 __dump_stack+0x30/0x40 lib/dump_stack.c:94
 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120
 dump_stack+0x1c/0x28 lib/dump_stack.c:129
 lockdep_rcu_suspicious+0x168/0x274 kernel/locking/lockdep.c:6871
 task_cls_state+0x1d0/0x1f0 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+0x1c/0x6c net/core/filter.c:3086
 bpf_prog_cd2e46495e8fe8a5+0x4c/0x70
 bpf_dispatcher_nop_func include/linux/bpf.h:1322 [inline]
 __bpf_prog_run include/linux/filter.h:718 [inline]
 bpf_prog_run include/linux/filter.h:725 [inline]
 bpf_prog_run_pin_on_cpu+0x70/0x1e8 include/linux/filter.h:742
 bpf_prog_test_run_syscall+0x2fc/0x4ac net/bpf/test_run.c:1564
 bpf_prog_test_run+0x2b4/0x33c kernel/bpf/syscall.c:4429
 __sys_bpf+0x4b0/0x614 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+0x80/0x98 kernel/bpf/syscall.c:5941
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
 el0_svc+0x58/0x180 arch/arm64/kernel/entry-common.c:879
 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:898
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596