[ 16.852680][ T3892] 8021q: adding VLAN 0 to HW filter on device bond0 [ 16.858076][ T3892] eql: remember to turn off Van-Jacobson compression on your slave devices [ 16.902166][ T263] gvnic 0000:00:00.0 enp0s0: Device link is up. [ 16.905568][ T1954] IPv6: ADDRCONF(NETDEV_CHANGE): enp0s0: link becomes ready Starting sshd: OK syzkaller Warning: Permanently added '10.128.1.2' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 33.908637][ T4306] [ 33.909238][ T4306] ============================================ [ 33.910757][ T4306] WARNING: possible recursive locking detected [ 33.912305][ T4306] 6.1.15-syzkaller #0 Not tainted [ 33.913558][ T4306] -------------------------------------------- [ 33.915138][ T4306] syz-executor140/4306 is trying to acquire lock: [ 33.916715][ T4306] ffff0000d4d5e130 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: l2tp_tunnel_register+0x888/0x19f8 [ 33.919276][ T4306] [ 33.919276][ T4306] but task is already holding lock: [ 33.921118][ T4306] ffff0000cf697130 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: pppol2tp_connect+0x53c/0x1348 [ 33.923538][ T4306] [ 33.923538][ T4306] other info that might help us debug this: [ 33.925547][ T4306] Possible unsafe locking scenario: [ 33.925547][ T4306] [ 33.927427][ T4306] CPU0 [ 33.928260][ T4306] ---- [ 33.929088][ T4306] lock(sk_lock-AF_PPPOX); [ 33.930194][ T4306] lock(sk_lock-AF_PPPOX); [ 33.931312][ T4306] [ 33.931312][ T4306] *** DEADLOCK *** [ 33.931312][ T4306] [ 33.933324][ T4306] May be due to missing lock nesting notation [ 33.933324][ T4306] [ 33.935403][ T4306] 1 lock held by syz-executor140/4306: [ 33.936761][ T4306] #0: ffff0000cf697130 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: pppol2tp_connect+0x53c/0x1348 [ 33.939259][ T4306] [ 33.939259][ T4306] stack backtrace: [ 33.940713][ T4306] CPU: 0 PID: 4306 Comm: syz-executor140 Not tainted 6.1.15-syzkaller #0 [ 33.942893][ T4306] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023 [ 33.945441][ T4306] Call trace: [ 33.946287][ T4306] dump_backtrace+0x1c8/0x1f4 [ 33.947417][ T4306] show_stack+0x2c/0x3c [ 33.948432][ T4306] dump_stack_lvl+0x108/0x170 [ 33.949588][ T4306] dump_stack+0x1c/0x58 [ 33.950597][ T4306] __lock_acquire+0x6310/0x764c [ 33.951818][ T4306] lock_acquire+0x2f8/0x8dc [ 33.952961][ T4306] lock_sock_nested+0x78/0x138 [ 33.954195][ T4306] l2tp_tunnel_register+0x888/0x19f8 [ 33.955497][ T4306] pppol2tp_connect+0x944/0x1348 [ 33.956724][ T4306] __sys_connect+0x268/0x290 [ 33.957907][ T4306] __arm64_sys_connect+0x7c/0x94 [ 33.959139][ T4306] invoke_syscall+0x98/0x2c0 [ 33.960292][ T4306] el0_svc_common+0x138/0x258 [ 33.961465][ T4306] do_el0_svc+0x64/0x218 [ 33.962526][ T4306] el0_svc+0x58/0x168 [ 33.963533][ T4306] el0t_64_sync_handler+0x84/0xf0 [ 33.964812][ T4306] el0t_64_sync+0x18c/0x190