[ 16.942231][ T3893] 8021q: adding VLAN 0 to HW filter on device bond0 [ 16.951895][ T3893] eql: remember to turn off Van-Jacobson compression on your slave devices [ 16.998944][ T11] gvnic 0000:00:00.0 enp0s0: Device link is up. [ 17.003399][ T111] IPv6: ADDRCONF(NETDEV_CHANGE): enp0s0: link becomes ready Starting sshd: OK syzkaller Warning: Permanently added '10.128.0.20' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 34.564949][ T4314] [ 34.565641][ T4314] ============================================ [ 34.567167][ T4314] WARNING: possible recursive locking detected [ 34.568679][ T4314] 6.1.15-syzkaller #0 Not tainted [ 34.569943][ T4314] -------------------------------------------- [ 34.571569][ T4314] syz-executor322/4314 is trying to acquire lock: [ 34.573183][ T4314] ffff0000c232e130 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: l2tp_tunnel_register+0x888/0x19f8 [ 34.575710][ T4314] [ 34.575710][ T4314] but task is already holding lock: [ 34.577597][ T4314] ffff0000c7cbd130 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: pppol2tp_connect+0x53c/0x1348 [ 34.580038][ T4314] [ 34.580038][ T4314] other info that might help us debug this: [ 34.582094][ T4314] Possible unsafe locking scenario: [ 34.582094][ T4314] [ 34.583974][ T4314] CPU0 [ 34.584808][ T4314] ---- [ 34.585670][ T4314] lock(sk_lock-AF_PPPOX); [ 34.586832][ T4314] lock(sk_lock-AF_PPPOX); [ 34.587984][ T4314] [ 34.587984][ T4314] *** DEADLOCK *** [ 34.587984][ T4314] [ 34.590035][ T4314] May be due to missing lock nesting notation [ 34.590035][ T4314] [ 34.592138][ T4314] 1 lock held by syz-executor322/4314: [ 34.593497][ T4314] #0: ffff0000c7cbd130 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: pppol2tp_connect+0x53c/0x1348 [ 34.596081][ T4314] [ 34.596081][ T4314] stack backtrace: [ 34.597589][ T4314] CPU: 0 PID: 4314 Comm: syz-executor322 Not tainted 6.1.15-syzkaller #0 [ 34.599660][ T4314] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023 [ 34.602247][ T4314] Call trace: [ 34.603070][ T4314] dump_backtrace+0x1c8/0x1f4 [ 34.604236][ T4314] show_stack+0x2c/0x3c [ 34.605335][ T4314] dump_stack_lvl+0x108/0x170 [ 34.606477][ T4314] dump_stack+0x1c/0x58 [ 34.607537][ T4314] __lock_acquire+0x6310/0x764c [ 34.608767][ T4314] lock_acquire+0x2f8/0x8dc [ 34.609884][ T4314] lock_sock_nested+0x78/0x138 [ 34.611103][ T4314] l2tp_tunnel_register+0x888/0x19f8 [ 34.612414][ T4314] pppol2tp_connect+0x944/0x1348 [ 34.613580][ T4314] __sys_connect+0x268/0x290 [ 34.614667][ T4314] __arm64_sys_connect+0x7c/0x94 [ 34.615885][ T4314] invoke_syscall+0x98/0x2c0 [ 34.617035][ T4314] el0_svc_common+0x138/0x258 [ 34.618244][ T4314] do_el0_svc+0x64/0x218 [ 34.619300][ T4314] el0_svc+0x58/0x168 [ 34.620357][ T4314] el0t_64_sync_handler+0x84/0xf0 [ 34.621630][ T4314] el0t_64_sync+0x18c/0x190