====================================================== WARNING: possible circular locking dependency detected 6.2.0-rc4-next-20230118-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.5/24576 is trying to acquire lock: ffff888027cf33b0 (slock-AF_INET6){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:355 [inline] ffff888027cf33b0 (slock-AF_INET6){+.-.}-{2:2}, at: release_sock+0x1f/0x1b0 net/core/sock.c:3483 but task is already holding lock: ffff888027cf36b8 (clock-AF_INET6){++..}-{2:2}, at: l2tp_tunnel_register+0x1c3/0xd80 net/l2tp/l2tp_core.c:1484 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (clock-AF_INET6){++..}-{2:2}: __raw_read_lock_bh include/linux/rwlock_api_smp.h:176 [inline] _raw_read_lock_bh+0x3f/0x70 kernel/locking/spinlock.c:252 sock_i_uid+0x1f/0xb0 net/core/sock.c:2564 sk_reuseport_match net/ipv4/inet_connection_sock.c:401 [inline] inet_csk_get_port+0x85f/0x26d0 net/ipv4/inet_connection_sock.c:532 __inet6_bind+0x625/0x1bb0 net/ipv6/af_inet6.c:413 inet6_bind+0x177/0x220 net/ipv6/af_inet6.c:472 __sys_bind+0x1ed/0x260 net/socket.c:1801 __do_sys_bind net/socket.c:1812 [inline] __se_sys_bind net/socket.c:1810 [inline] __x64_sys_bind+0x73/0xb0 net/socket.c:1810 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd -> #1 (&tcp_hashinfo.bhash[i].lock){+.-.}-{2:2}: __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:350 [inline] __inet_inherit_port+0x2b5/0x18c0 net/ipv4/inet_hashtables.c:230 tcp_v4_syn_recv_sock+0xb5a/0x14b0 net/ipv4/tcp_ipv4.c:1628 tcp_v6_syn_recv_sock+0x14e1/0x2360 net/ipv6/tcp_ipv6.c:1220 tcp_get_cookie_sock+0xcd/0x860 net/ipv4/syncookies.c:207 cookie_v4_check+0x1553/0x25e0 net/ipv4/syncookies.c:448 tcp_v4_cookie_check net/ipv4/tcp_ipv4.c:1670 [inline] tcp_v4_do_rcv+0x8d9/0x9d0 net/ipv4/tcp_ipv4.c:1730 tcp_v4_rcv+0x306c/0x3280 net/ipv4/tcp_ipv4.c:2132 ip_protocol_deliver_rcu+0x9f/0x480 net/ipv4/ip_input.c:205 ip_local_deliver_finish+0x2ec/0x4f0 net/ipv4/ip_input.c:233 NF_HOOK include/linux/netfilter.h:302 [inline] NF_HOOK include/linux/netfilter.h:296 [inline] ip_local_deliver+0x1ae/0x200 net/ipv4/ip_input.c:254 dst_input include/net/dst.h:454 [inline] ip_rcv_finish+0x1cf/0x2f0 net/ipv4/ip_input.c:449 NF_HOOK include/linux/netfilter.h:302 [inline] NF_HOOK include/linux/netfilter.h:296 [inline] ip_rcv+0xae/0xd0 net/ipv4/ip_input.c:569 __netif_receive_skb_one_core+0x114/0x180 net/core/dev.c:5482 __netif_receive_skb+0x1f/0x1c0 net/core/dev.c:5596 process_backlog+0x13e/0x6d0 net/core/dev.c:5924 __napi_poll+0xaf/0x430 net/core/dev.c:6485 napi_poll net/core/dev.c:6552 [inline] net_rx_action+0x8da/0xc70 net/core/dev.c:6663 __do_softirq+0x2e3/0xae3 kernel/softirq.c:571 invoke_softirq kernel/softirq.c:445 [inline] __irq_exit_rcu+0x114/0x190 kernel/softirq.c:650 irq_exit_rcu+0x9/0x20 kernel/softirq.c:662 sysvec_apic_timer_interrupt+0x97/0xc0 arch/x86/kernel/apic/apic.c:1107 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:649 arch_local_irq_restore arch/x86/include/asm/irqflags.h:134 [inline] lock_acquire.part.0+0x156/0x350 kernel/locking/lockdep.c:5693 rcu_lock_acquire include/linux/rcupdate.h:327 [inline] rcu_read_lock include/linux/rcupdate.h:773 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline] batadv_nc_worker+0x131/0xfe0 net/batman-adv/network-coding.c:719 process_one_work+0x9bf/0x1750 kernel/workqueue.c:2390 worker_thread+0x669/0x1090 kernel/workqueue.c:2537 kthread+0x2e8/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 -> #0 (slock-AF_INET6){+.-.}-{2:2}: check_prev_add kernel/locking/lockdep.c:3107 [inline] check_prevs_add kernel/locking/lockdep.c:3226 [inline] validate_chain kernel/locking/lockdep.c:3841 [inline] __lock_acquire+0x2a9d/0x5780 kernel/locking/lockdep.c:5073 lock_acquire.part.0+0x11c/0x350 kernel/locking/lockdep.c:5690 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x33/0x40 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:355 [inline] release_sock+0x1f/0x1b0 net/core/sock.c:3483 l2tp_tunnel_register+0x2e0/0xd80 net/l2tp/l2tp_core.c:1487 pppol2tp_connect+0xcdc/0x1a80 net/l2tp/l2tp_ppp.c:723 __sys_connect_file+0x153/0x1a0 net/socket.c:2001 __sys_connect+0x165/0x1a0 net/socket.c:2018 __do_sys_connect net/socket.c:2028 [inline] __se_sys_connect net/socket.c:2025 [inline] __x64_sys_connect+0x73/0xb0 net/socket.c:2025 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd other info that might help us debug this: Chain exists of: slock-AF_INET6 --> &tcp_hashinfo.bhash[i].lock --> clock-AF_INET6 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(clock-AF_INET6); lock(&tcp_hashinfo.bhash[i].lock); lock(clock-AF_INET6); lock(slock-AF_INET6); *** DEADLOCK *** 3 locks held by syz-executor.5/24576: #0: ffff888083ee6130 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1725 [inline] #0: ffff888083ee6130 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: pppol2tp_connect+0xadc/0x1a80 net/l2tp/l2tp_ppp.c:675 #1: ffff888027cf3430 (sk_lock-AF_INET6){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1725 [inline] #1: ffff888027cf3430 (sk_lock-AF_INET6){+.+.}-{0:0}, at: l2tp_tunnel_register+0x1af/0xd80 net/l2tp/l2tp_core.c:1483 #2: ffff888027cf36b8 (clock-AF_INET6){++..}-{2:2}, at: l2tp_tunnel_register+0x1c3/0xd80 net/l2tp/l2tp_core.c:1484 stack backtrace: CPU: 0 PID: 24576 Comm: syz-executor.5 Not tainted 6.2.0-rc4-next-20230118-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2187 check_prev_add kernel/locking/lockdep.c:3107 [inline] check_prevs_add kernel/locking/lockdep.c:3226 [inline] validate_chain kernel/locking/lockdep.c:3841 [inline] __lock_acquire+0x2a9d/0x5780 kernel/locking/lockdep.c:5073 lock_acquire.part.0+0x11c/0x350 kernel/locking/lockdep.c:5690 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x33/0x40 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:355 [inline] release_sock+0x1f/0x1b0 net/core/sock.c:3483 l2tp_tunnel_register+0x2e0/0xd80 net/l2tp/l2tp_core.c:1487 pppol2tp_connect+0xcdc/0x1a80 net/l2tp/l2tp_ppp.c:723 __sys_connect_file+0x153/0x1a0 net/socket.c:2001 __sys_connect+0x165/0x1a0 net/socket.c:2018 __do_sys_connect net/socket.c:2028 [inline] __se_sys_connect net/socket.c:2025 [inline] __x64_sys_connect+0x73/0xb0 net/socket.c:2025 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f35b3a8c0c9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f35b475c168 EFLAGS: 00000246 ORIG_RAX: 000000000000002a RAX: ffffffffffffffda RBX: 00007f35b3babf80 RCX: 00007f35b3a8c0c9 RDX: 000000000000002e RSI: 0000000020000080 RDI: 0000000000000003 RBP: 00007f35b3ae7ae9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffdef90528f R14: 00007f35b475c300 R15: 0000000000022000