TCP: request_sock_TCP: Possible SYN flooding on port [::]:2. Sending cookies.
======================================================
WARNING: possible circular locking dependency detected
6.6.0-rc4-next-20231005-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.3/5195 is trying to acquire lock:
ffff88807a574578 (&p->pi_lock){-.-.}-{2:2}, at: class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:518 [inline]
ffff88807a574578 (&p->pi_lock){-.-.}-{2:2}, at: try_to_wake_up+0xb0/0x15d0 kernel/sched/core.c:4213

but task is already holding lock:
ffffffff8cb98e18 ((console_sem).lock){-.-.}-{2:2}, at: up+0x16/0xb0 kernel/locking/semaphore.c:187

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 ((console_sem).lock){-.-.}-{2:2}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x3a/0x50 kernel/locking/spinlock.c:162
       down_trylock+0x12/0x70 kernel/locking/semaphore.c:139
       __down_trylock_console_sem+0x40/0x140 kernel/printk/printk.c:323
       console_trylock+0x73/0x130 kernel/printk/printk.c:2652
       console_trylock_spinning kernel/printk/printk.c:1924 [inline]
       vprintk_emit+0x162/0x5f0 kernel/printk/printk.c:2303
       vprintk+0x7b/0x90 kernel/printk/printk_safe.c:45
       _printk+0xc8/0x100 kernel/printk/printk.c:2329
       pick_eevdf kernel/sched/fair.c:963 [inline]
       pick_next_entity kernel/sched/fair.c:5247 [inline]
       pick_next_task_fair+0x1c5/0x1280 kernel/sched/fair.c:8205
       __pick_next_task kernel/sched/core.c:5986 [inline]
       pick_next_task kernel/sched/core.c:6061 [inline]
       __schedule+0x493/0x5a00 kernel/sched/core.c:6640
       __schedule_loop kernel/sched/core.c:6753 [inline]
       schedule+0xe7/0x270 kernel/sched/core.c:6768
       worker_thread+0x2e1/0x1290 kernel/workqueue.c:2799
       kthread+0x33c/0x440 kernel/kthread.c:388
       ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304

-> #1 (&rq->__lock){-.-.}-{2:2}:
       _raw_spin_lock_nested+0x31/0x40 kernel/locking/spinlock.c:378
       raw_spin_rq_lock_nested+0x29/0x130 kernel/sched/core.c:558
       raw_spin_rq_lock kernel/sched/sched.h:1357 [inline]
       rq_lock kernel/sched/sched.h:1671 [inline]
       task_fork_fair+0x70/0x240 kernel/sched/fair.c:12399
       sched_cgroup_fork+0x3cf/0x510 kernel/sched/core.c:4799
       copy_process+0x4580/0x74b0 kernel/fork.c:2609
       kernel_clone+0xfd/0x920 kernel/fork.c:2907
       user_mode_thread+0xb4/0xf0 kernel/fork.c:2985
       rest_init+0x27/0x2b0 init/main.c:691
       arch_call_rest_init+0x13/0x30 init/main.c:823
       start_kernel+0x39f/0x480 init/main.c:1068
       x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:556
       x86_64_start_kernel+0xb2/0xc0 arch/x86/kernel/head64.c:537
       secondary_startup_64_no_verify+0x166/0x16b

-> #0 (&p->pi_lock){-.-.}-{2:2}:
       check_prev_add kernel/locking/lockdep.c:3134 [inline]
       check_prevs_add kernel/locking/lockdep.c:3253 [inline]
       validate_chain kernel/locking/lockdep.c:3868 [inline]
       __lock_acquire+0x2e3d/0x5de0 kernel/locking/lockdep.c:5136
       lock_acquire kernel/locking/lockdep.c:5753 [inline]
       lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5718
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x3a/0x50 kernel/locking/spinlock.c:162
       class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:518 [inline]
       try_to_wake_up+0xb0/0x15d0 kernel/sched/core.c:4213
       up+0x79/0xb0 kernel/locking/semaphore.c:191
       __up_console_sem kernel/printk/printk.c:340 [inline]
       __console_unlock kernel/printk/printk.c:2699 [inline]
       console_unlock+0x1cf/0x260 kernel/printk/printk.c:3031
       vprintk_emit+0x17f/0x5f0 kernel/printk/printk.c:2304
       vprintk+0x7b/0x90 kernel/printk/printk_safe.c:45
       _printk+0xc8/0x100 kernel/printk/printk.c:2329
       tcp_syn_flood_action+0x3fb/0x460 net/ipv4/tcp_input.c:6895
       tcp_conn_request+0x1758/0x34a0 net/ipv4/tcp_input.c:6992
       tcp_v4_conn_request net/ipv4/tcp_ipv4.c:1543 [inline]
       tcp_v4_conn_request+0xc5/0x250 net/ipv4/tcp_ipv4.c:1537
       tcp_v6_conn_request+0x2e4/0x460 net/ipv6/tcp_ipv6.c:1164
       tcp_rcv_state_process+0x11bb/0x4d00 net/ipv4/tcp_input.c:6533
       tcp_v4_do_rcv+0x346/0x9e0 net/ipv4/tcp_ipv4.c:1752
       tcp_v4_rcv+0x363f/0x3b40 net/ipv4/tcp_ipv4.c:2141
       ip_protocol_deliver_rcu+0x9f/0x480 net/ipv4/ip_input.c:205
       ip_local_deliver_finish+0x2e4/0x510 net/ipv4/ip_input.c:233
       NF_HOOK include/linux/netfilter.h:304 [inline]
       NF_HOOK include/linux/netfilter.h:298 [inline]
       ip_local_deliver+0x1b6/0x550 net/ipv4/ip_input.c:254
       dst_input include/net/dst.h:468 [inline]
       ip_rcv_finish+0x1c4/0x2e0 net/ipv4/ip_input.c:449
       NF_HOOK include/linux/netfilter.h:304 [inline]
       NF_HOOK include/linux/netfilter.h:298 [inline]
       ip_rcv+0xc9/0x430 net/ipv4/ip_input.c:569
       __netif_receive_skb_one_core+0x115/0x180 net/core/dev.c:5523
       __netif_receive_skb+0x1f/0x1b0 net/core/dev.c:5637
       process_backlog+0x101/0x6b0 net/core/dev.c:5965
       __napi_poll.constprop.0+0xb4/0x530 net/core/dev.c:6527
       napi_poll net/core/dev.c:6594 [inline]
       net_rx_action+0x956/0xe90 net/core/dev.c:6727
       __do_softirq+0x21a/0x968 kernel/softirq.c:553
       do_softirq kernel/softirq.c:454 [inline]
       do_softirq+0xaa/0xe0 kernel/softirq.c:441
       __local_bh_enable_ip+0xf8/0x120 kernel/softirq.c:381
       local_bh_enable include/linux/bottom_half.h:33 [inline]
       rcu_read_unlock_bh include/linux/rcupdate.h:819 [inline]
       __dev_queue_xmit+0xa6f/0x3d60 net/core/dev.c:4367
       dev_queue_xmit include/linux/netdevice.h:3092 [inline]
       neigh_hh_output include/net/neighbour.h:526 [inline]
       neigh_output include/net/neighbour.h:540 [inline]
       ip_finish_output2+0x169f/0x2550 net/ipv4/ip_output.c:233
       __ip_finish_output net/ipv4/ip_output.c:311 [inline]
       __ip_finish_output+0x38b/0x640 net/ipv4/ip_output.c:293
       ip_finish_output+0x31/0x310 net/ipv4/ip_output.c:321
       NF_HOOK_COND include/linux/netfilter.h:293 [inline]
       ip_output+0x13b/0x290 net/ipv4/ip_output.c:431
       dst_output include/net/dst.h:458 [inline]
       ip_local_out net/ipv4/ip_output.c:127 [inline]
       __ip_queue_xmit+0xa15/0x1df0 net/ipv4/ip_output.c:533
       __tcp_transmit_skb+0x1a39/0x3b30 net/ipv4/tcp_output.c:1409
       tcp_transmit_skb net/ipv4/tcp_output.c:1427 [inline]
       tcp_connect+0x3509/0x5430 net/ipv4/tcp_output.c:3958
       tcp_v4_connect+0x140e/0x1a90 net/ipv4/tcp_ipv4.c:323
       __inet_stream_connect+0x38b/0xe20 net/ipv4/af_inet.c:676
       inet_stream_connect+0x57/0xa0 net/ipv4/af_inet.c:740
       __sys_connect_file+0x15b/0x1a0 net/socket.c:2050
       __sys_connect+0x145/0x170 net/socket.c:2067
       __do_sys_connect net/socket.c:2077 [inline]
       __se_sys_connect net/socket.c:2074 [inline]
       __x64_sys_connect+0x72/0xb0 net/socket.c:2074
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

other info that might help us debug this:

Chain exists of:
  &p->pi_lock --> &rq->__lock --> (console_sem).lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock((console_sem).lock);
                               lock(&rq->__lock);
                               lock((console_sem).lock);
  lock(&p->pi_lock);

 *** DEADLOCK ***

7 locks held by syz-executor.3/5195:
 #0: ffff8880432f99b0 (sk_lock-AF_INET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1722 [inline]
 #0: ffff8880432f99b0 (sk_lock-AF_INET){+.+.}-{0:0}, at: inet_stream_connect+0x43/0xa0 net/ipv4/af_inet.c:739
 #1: ffffffff8cbab220 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:303 [inline]
 #1: ffffffff8cbab220 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:749 [inline]
 #1: ffffffff8cbab220 (rcu_read_lock){....}-{1:2}, at: __ip_queue_xmit+0x6d/0x1df0 net/ipv4/ip_output.c:468
 #2: ffffffff8cbab220 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:303 [inline]
 #2: ffffffff8cbab220 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:749 [inline]
 #2: ffffffff8cbab220 (rcu_read_lock){....}-{1:2}, at: ip_finish_output2+0x367/0x2550 net/ipv4/ip_output.c:226
 #3: ffffffff8cbab220 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:303 [inline]
 #3: ffffffff8cbab220 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:749 [inline]
 #3: ffffffff8cbab220 (rcu_read_lock){....}-{1:2}, at: process_backlog+0x25d/0x6b0 net/core/dev.c:5964
 #4: ffffffff8cbab220 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:303 [inline]
 #4: ffffffff8cbab220 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:749 [inline]
 #4: ffffffff8cbab220 (rcu_read_lock){....}-{1:2}, at: ip_local_deliver_finish+0x231/0x510 net/ipv4/ip_input.c:232
 #5: ffffffff8cbab220 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:303 [inline]
 #5: ffffffff8cbab220 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:749 [inline]
 #5: ffffffff8cbab220 (rcu_read_lock){....}-{1:2}, at: tcp_rcv_state_process+0x1130/0x4d00 net/ipv4/tcp_input.c:6531
 #6: ffffffff8cb98e18 ((console_sem).lock){-.-.}-{2:2}, at: up+0x16/0xb0 kernel/locking/semaphore.c:187

stack backtrace:
CPU: 1 PID: 5195 Comm: syz-executor.3 Not tainted 6.6.0-rc4-next-20231005-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
 check_noncircular+0x311/0x3f0 kernel/locking/lockdep.c:2187
 check_prev_add kernel/locking/lockdep.c:3134 [inline]
 check_prevs_add kernel/locking/lockdep.c:3253 [inline]
 validate_chain kernel/locking/lockdep.c:3868 [inline]
 __lock_acquire+0x2e3d/0x5de0 kernel/locking/lockdep.c:5136
 lock_acquire kernel/locking/lockdep.c:5753 [inline]
 lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5718
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0x3a/0x50 kernel/locking/spinlock.c:162
 class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:518 [inline]
 try_to_wake_up+0xb0/0x15d0 kernel/sched/core.c:4213
 up+0x79/0xb0 kernel/locking/semaphore.c:191
 __up_console_sem kernel/printk/printk.c:340 [inline]
 __console_unlock kernel/printk/printk.c:2699 [inline]
 console_unlock+0x1cf/0x260 kernel/printk/printk.c:3031
 vprintk_emit+0x17f/0x5f0 kernel/printk/printk.c:2304
 vprintk+0x7b/0x90 kernel/printk/printk_safe.c:45
 _printk+0xc8/0x100 kernel/printk/printk.c:2329
 tcp_syn_flood_action+0x3fb/0x460 net/ipv4/tcp_input.c:6895
 tcp_conn_request+0x1758/0x34a0 net/ipv4/tcp_input.c:6992
 tcp_v4_conn_request net/ipv4/tcp_ipv4.c:1543 [inline]
 tcp_v4_conn_request+0xc5/0x250 net/ipv4/tcp_ipv4.c:1537
 tcp_v6_conn_request+0x2e4/0x460 net/ipv6/tcp_ipv6.c:1164
 tcp_rcv_state_process+0x11bb/0x4d00 net/ipv4/tcp_input.c:6533
 tcp_v4_do_rcv+0x346/0x9e0 net/ipv4/tcp_ipv4.c:1752
 tcp_v4_rcv+0x363f/0x3b40 net/ipv4/tcp_ipv4.c:2141
 ip_protocol_deliver_rcu+0x9f/0x480 net/ipv4/ip_input.c:205
 ip_local_deliver_finish+0x2e4/0x510 net/ipv4/ip_input.c:233
 NF_HOOK include/linux/netfilter.h:304 [inline]
 NF_HOOK include/linux/netfilter.h:298 [inline]
 ip_local_deliver+0x1b6/0x550 net/ipv4/ip_input.c:254
 dst_input include/net/dst.h:468 [inline]
 ip_rcv_finish+0x1c4/0x2e0 net/ipv4/ip_input.c:449
 NF_HOOK include/linux/netfilter.h:304 [inline]
 NF_HOOK include/linux/netfilter.h:298 [inline]
 ip_rcv+0xc9/0x430 net/ipv4/ip_input.c:569
 __netif_receive_skb_one_core+0x115/0x180 net/core/dev.c:5523
 __netif_receive_skb+0x1f/0x1b0 net/core/dev.c:5637
 process_backlog+0x101/0x6b0 net/core/dev.c:5965
 __napi_poll.constprop.0+0xb4/0x530 net/core/dev.c:6527
 napi_poll net/core/dev.c:6594 [inline]
 net_rx_action+0x956/0xe90 net/core/dev.c:6727
 __do_softirq+0x21a/0x968 kernel/softirq.c:553
 do_softirq kernel/softirq.c:454 [inline]
 do_softirq+0xaa/0xe0 kernel/softirq.c:441
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0xf8/0x120 kernel/softirq.c:381
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 rcu_read_unlock_bh include/linux/rcupdate.h:819 [inline]
 __dev_queue_xmit+0xa6f/0x3d60 net/core/dev.c:4367
 dev_queue_xmit include/linux/netdevice.h:3092 [inline]
 neigh_hh_output include/net/neighbour.h:526 [inline]
 neigh_output include/net/neighbour.h:540 [inline]
 ip_finish_output2+0x169f/0x2550 net/ipv4/ip_output.c:233
 __ip_finish_output net/ipv4/ip_output.c:311 [inline]
 __ip_finish_output+0x38b/0x640 net/ipv4/ip_output.c:293
 ip_finish_output+0x31/0x310 net/ipv4/ip_output.c:321
 NF_HOOK_COND include/linux/netfilter.h:293 [inline]
 ip_output+0x13b/0x290 net/ipv4/ip_output.c:431
 dst_output include/net/dst.h:458 [inline]
 ip_local_out net/ipv4/ip_output.c:127 [inline]
 __ip_queue_xmit+0xa15/0x1df0 net/ipv4/ip_output.c:533
 __tcp_transmit_skb+0x1a39/0x3b30 net/ipv4/tcp_output.c:1409
 tcp_transmit_skb net/ipv4/tcp_output.c:1427 [inline]
 tcp_connect+0x3509/0x5430 net/ipv4/tcp_output.c:3958
 tcp_v4_connect+0x140e/0x1a90 net/ipv4/tcp_ipv4.c:323
 __inet_stream_connect+0x38b/0xe20 net/ipv4/af_inet.c:676
 inet_stream_connect+0x57/0xa0 net/ipv4/af_inet.c:740
 __sys_connect_file+0x15b/0x1a0 net/socket.c:2050
 __sys_connect+0x145/0x170 net/socket.c:2067
 __do_sys_connect net/socket.c:2077 [inline]
 __se_sys_connect net/socket.c:2074 [inline]
 __x64_sys_connect+0x72/0xb0 net/socket.c:2074
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f08b3e7cae9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f08b4bdf0c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007f08b3f9bf80 RCX: 00007f08b3e7cae9
RDX: 0000000000000010 RSI: 00000000200001c0 RDI: 0000000000000003
RBP: 00007f08b3ec847a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f08b3f9bf80 R15: 00007ffd8804fc08
 </TASK>
TCP: request_sock_TCP: Possible SYN flooding on port [::]:2. Sending cookies.
EEVDF scheduling fail, picking leftmost
TCP: request_sock_TCP: Possible SYN flooding on port [::]:2. Sending cookies.
TCP: request_sock_TCP: Possible SYN flooding on port [::]:2. Sending cookies.
TCP: request_sock_TCP: Possible SYN flooding on port [::]:2. Sending cookies.
TCP: request_sock_TCP: Possible SYN flooding on port [::]:2. Sending cookies.
TCP: request_sock_TCP: Possible SYN flooding on port [::]:2. Sending cookies.
TCP: request_sock_TCP: Possible SYN flooding on port [::]:2. Sending cookies.
EEVDF scheduling fail, picking leftmost
TCP: request_sock_TCP: Possible SYN flooding on port [::]:2. Sending cookies.
TCP: request_sock_TCP: Possible SYN flooding on port [::]:2. Sending cookies.
EEVDF scheduling fail, picking leftmost
EEVDF scheduling fail, picking leftmost
EEVDF scheduling fail, picking leftmost