netlink: 'syz.4.2593': attribute type 20 has an invalid length.
============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz.4.2593/13665 is trying to acquire lock:
ffff888060598218 (&qs->lock){..-.}-{2:2}, at: __stack_map_get+0x11e/0x450 kernel/bpf/queue_stack_maps.c:140

but task is already holding lock:
ffff888060598218 (&qs->lock){..-.}-{2:2}, at: __stack_map_get+0x11e/0x450 kernel/bpf/queue_stack_maps.c:140

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&qs->lock);
  lock(&qs->lock);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

3 locks held by syz.4.2593/13665:
 #0: ffffffff8cd2fc20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 #0: ffffffff8cd2fc20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
 #0: ffffffff8cd2fc20 (rcu_read_lock){....}-{1:2}, at: bpf_test_timer_enter+0x1a/0x140 net/bpf/test_run.c:39
 #1: ffff888060598218 (&qs->lock){..-.}-{2:2}, at: __stack_map_get+0x11e/0x450 kernel/bpf/queue_stack_maps.c:140
 #2: ffffffff8cd2fc20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 #2: ffffffff8cd2fc20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
 #2: ffffffff8cd2fc20 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2321 [inline]
 #2: ffffffff8cd2fc20 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0xde/0x3c0 kernel/trace/bpf_trace.c:2361

stack backtrace:
CPU: 0 PID: 13665 Comm: syz.4.2593 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/14/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
 check_deadlock kernel/locking/lockdep.c:3062 [inline]
 validate_chain kernel/locking/lockdep.c:3856 [inline]
 __lock_acquire+0x5d40/0x7c80 kernel/locking/lockdep.c:5137
 lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0xa8/0xf0 kernel/locking/spinlock.c:162
 __stack_map_get+0x11e/0x450 kernel/bpf/queue_stack_maps.c:140
 bpf_prog_00798911c748094f+0x42/0x46
 bpf_dispatcher_nop_func include/linux/bpf.h:1213 [inline]
 __bpf_prog_run include/linux/filter.h:612 [inline]
 bpf_prog_run include/linux/filter.h:619 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2322 [inline]
 bpf_trace_run2+0x1d1/0x3c0 kernel/trace/bpf_trace.c:2361
 __bpf_trace_contention_end+0xdd/0x130 include/trace/events/lock.h:122
 trace_contention_end+0xe6/0x110 include/trace/events/lock.h:122
 __pv_queued_spin_lock_slowpath+0x7ec/0x9d0 kernel/locking/qspinlock.c:560
 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:586 [inline]
 queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline]
 queued_spin_lock include/asm-generic/qspinlock.h:114 [inline]
 do_raw_spin_lock+0x24e/0x2c0 kernel/locking/spinlock_debug.c:115
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline]
 _raw_spin_lock_irqsave+0xb4/0xf0 kernel/locking/spinlock.c:162
 __stack_map_get+0x11e/0x450 kernel/bpf/queue_stack_maps.c:140
 bpf_prog_00798911c748094f+0x42/0x46
 __bpf_prog_run include/linux/filter.h:612 [inline]
 bpf_prog_run_xdp include/net/xdp.h:496 [inline]
 bpf_test_run+0x390/0x810 net/bpf/test_run.c:422
 bpf_prog_test_run_xdp+0x741/0xfa0 net/bpf/test_run.c:1261
 bpf_prog_test_run+0x321/0x390 kernel/bpf/syscall.c:4123
 __sys_bpf+0x440/0x800 kernel/bpf/syscall.c:5485
 __do_sys_bpf kernel/bpf/syscall.c:5571 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5569 [inline]
 __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5569
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fd95ff8ebe9
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:00007fd960db6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007fd9601c6090 RCX: 00007fd95ff8ebe9
RDX: 0000000000000050 RSI: 0000200000000000 RDI: 000000000000000a
RBP: 00007fd960011e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd9601c6128 R14: 00007fd9601c6090 R15: 00007fff71bf5778
 </TASK>