============================= WARNING: suspicious RCU usage 6.15.0-rc4-syzkaller #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.2.16/4404: #0: ffffffff841f3898 (rcu_read_lock_trace){....}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff841f3898 (rcu_read_lock_trace){....}-{0:0}, at: rcu_read_lock_trace+0x16/0x40 include/linux/rcupdate_trace.h:58 stack backtrace: CPU: 1 UID: 0 PID: 4404 Comm: syz.2.16 Not tainted 6.15.0-rc4-syzkaller #0 PREEMPT(undef) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: dump_stack_lvl+0xad/0x110 lib/dump_stack.c:120 lockdep_rcu_suspicious+0x128/0x170 kernel/locking/lockdep.c:6865 task_cls_state+0xa3/0xb0 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:3086 [inline] bpf_get_cgroup_classid_curr+0x12/0x20 net/core/filter.c:3084 ___bpf_prog_run+0x601/0x2610 kernel/bpf/core.c:2018 __bpf_prog_run32+0xba/0xe0 kernel/bpf/core.c:2311 bpf_dispatcher_nop_func include/linux/bpf.h:1316 [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+0x24/0x90 include/linux/filter.h:742 bpf_prog_test_run_syscall+0xe1/0x160 net/bpf/test_run.c:1564 bpf_prog_test_run+0xe0/0x100 kernel/bpf/syscall.c:4428 __sys_bpf+0x2e4/0x590 kernel/bpf/syscall.c:5853 __do_sys_bpf kernel/bpf/syscall.c:5942 [inline] __se_sys_bpf kernel/bpf/syscall.c:5940 [inline] __x64_sys_bpf+0x17/0x20 kernel/bpf/syscall.c:5940 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xa4/0x180 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f3817d8e969 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f3818b21038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007f3817fb5fa0 RCX: 00007f3817d8e969 RDX: 0000000000000048 RSI: 0000200000000500 RDI: 000000000000000a RBP: 00007f3817e10ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f3817fb5fa0 R15: 00007ffd6d7ff008