Warning: Permanently added '10.128.0.102' (ECDSA) to the list of known hosts.
executing program
[   41.525785][ T4051] 
[   41.526416][ T4051] ============================================
[   41.527866][ T4051] WARNING: possible recursive locking detected
[   41.529205][ T4051] 5.15.98-syzkaller #0 Not tainted
[   41.530329][ T4051] --------------------------------------------
[   41.531799][ T4051] syz-executor154/4051 is trying to acquire lock:
[   41.533303][ T4051] ffff0000c26fd120 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: l2tp_tunnel_register+0x888/0x1974
[   41.535725][ T4051] 
[   41.535725][ T4051] but task is already holding lock:
[   41.537406][ T4051] ffff0000c1006120 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: pppol2tp_connect+0x53c/0x1348
[   41.539716][ T4051] 
[   41.539716][ T4051] other info that might help us debug this:
[   41.541558][ T4051]  Possible unsafe locking scenario:
[   41.541558][ T4051] 
[   41.543286][ T4051]        CPU0
[   41.544074][ T4051]        ----
[   41.544844][ T4051]   lock(sk_lock-AF_PPPOX);
[   41.545899][ T4051]   lock(sk_lock-AF_PPPOX);
[   41.546959][ T4051] 
[   41.546959][ T4051]  *** DEADLOCK ***
[   41.546959][ T4051] 
[   41.548857][ T4051]  May be due to missing lock nesting notation
[   41.548857][ T4051] 
[   41.550877][ T4051] 1 lock held by syz-executor154/4051:
[   41.552120][ T4051]  #0: ffff0000c1006120 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: pppol2tp_connect+0x53c/0x1348
[   41.554464][ T4051] 
[   41.554464][ T4051] stack backtrace:
[   41.555844][ T4051] CPU: 1 PID: 4051 Comm: syz-executor154 Not tainted 5.15.98-syzkaller #0
[   41.557807][ T4051] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
[   41.560172][ T4051] Call trace:
[   41.560947][ T4051]  dump_backtrace+0x0/0x530
[   41.562031][ T4051]  show_stack+0x2c/0x3c
[   41.562989][ T4051]  dump_stack_lvl+0x108/0x170
[   41.564080][ T4051]  dump_stack+0x1c/0x58
[   41.565085][ T4051]  __lock_acquire+0x62b4/0x7620
[   41.566268][ T4051]  lock_acquire+0x2b8/0x894
[   41.567303][ T4051]  lock_sock_nested+0xec/0x1ec
[   41.568421][ T4051]  l2tp_tunnel_register+0x888/0x1974
[   41.569722][ T4051]  pppol2tp_connect+0x944/0x1348
[   41.570846][ T4051]  __sys_connect+0x268/0x290
[   41.571896][ T4051]  __arm64_sys_connect+0x7c/0x94
[   41.573031][ T4051]  invoke_syscall+0x98/0x2b8
[   41.574062][ T4051]  el0_svc_common+0x138/0x258
[   41.575179][ T4051]  do_el0_svc+0x58/0x14c
[   41.576138][ T4051]  el0_svc+0x7c/0x1f0
[   41.577081][ T4051]  el0t_64_sync_handler+0x84/0xe4
[   41.578285][ T4051]  el0t_64_sync+0x1a0/0x1a4