rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P11060/2:b..l rcu: (detected by 1, t=10503 jiffies, g=53513, q=1653096 ncpus=2) task:syz.4.1240 state:R running task stack:24832 pid:11060 tgid:11059 ppid:10115 flags:0x00000000 Call Trace: context_switch kernel/sched/core.c:5315 [inline] __schedule+0x1895/0x4b30 kernel/sched/core.c:6675 preempt_schedule_common+0x84/0xd0 kernel/sched/core.c:6854 preempt_schedule+0xe1/0xf0 kernel/sched/core.c:6878 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12 __local_bh_enable_ip+0x179/0x200 kernel/softirq.c:389 local_bh_enable include/linux/bottom_half.h:33 [inline] rcu_read_unlock_bh include/linux/rcupdate.h:919 [inline] __dev_queue_xmit+0x1764/0x3e80 net/core/dev.c:4451 dev_queue_xmit include/linux/netdevice.h:3094 [inline] neigh_hh_output include/net/neighbour.h:526 [inline] neigh_output include/net/neighbour.h:540 [inline] ip_finish_output2+0xd41/0x1390 net/ipv4/ip_output.c:236 ip_local_out net/ipv4/ip_output.c:130 [inline] __ip_queue_xmit+0x118c/0x1b80 net/ipv4/ip_output.c:536 __tcp_transmit_skb+0x2544/0x3b30 net/ipv4/tcp_output.c:1466 tcp_transmit_skb net/ipv4/tcp_output.c:1484 [inline] tcp_send_syn_data net/ipv4/tcp_output.c:4059 [inline] tcp_connect+0x2c21/0x4940 net/ipv4/tcp_output.c:4145 tcp_v4_connect+0x1127/0x1ba0 net/ipv4/tcp_ipv4.c:341 __inet_stream_connect+0x262/0xf30 net/ipv4/af_inet.c:679 tcp_sendmsg_fastopen+0x3a2/0x5d0 net/ipv4/tcp.c:1038 tcp_sendmsg_locked+0x4a23/0x50a0 net/ipv4/tcp.c:1090 tcp_sendmsg+0x30/0x50 net/ipv4/tcp.c:1357 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x1a6/0x270 net/socket.c:745 __sys_sendto+0x39b/0x4f0 net/socket.c:2210 __do_sys_sendto net/socket.c:2222 [inline] __se_sys_sendto net/socket.c:2218 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2218 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f956eb7dff9 RSP: 002b:00007f956f917038 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f956ed35f80 RCX: 00007f956eb7dff9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005 RBP: 00007f956ebf0296 R08: 0000000020e68000 R09: 0000000000000010 R10: 00000000200007fd R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f956ed35f80 R15: 00007ffd3a909918 rcu: rcu_preempt kthread starved for 10544 jiffies! g53513 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_preempt state:R running task stack:21840 pid:17 tgid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5315 [inline] __schedule+0x1895/0x4b30 kernel/sched/core.c:6675 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:6997 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__try_to_del_timer_sync+0x0/0x340 kernel/time/timer.c:1499 Code: 89 fb e8 a3 50 13 00 48 89 df 31 f6 5b eb 1b 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 55 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 e4 e0 48 RSP: 0018:ffffc90000167ab8 EFLAGS: 00000293 RAX: ffffffff81816a74 RBX: 0000000000000000 RCX: ffff88801ce98000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffc90000167bc0 RBP: ffffc90000167b90 R08: ffffffff81816a28 R09: 1ffffffff2039f15 R10: dffffc0000000000 R11: fffffbfff2039f16 R12: 1ffff9200002cf5c R13: ffffc90000167bc0 R14: 0000000000000000 R15: dffffc0000000000 __timer_delete_sync+0x245/0x310 kernel/time/timer.c:1667 timer_delete_sync kernel/time/timer.c:1722 [inline] del_timer_sync include/linux/timer.h:185 [inline] schedule_timeout+0x1c8/0x310 kernel/time/timer.c:2616 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2045 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2247 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 9 Comm: kworker/0:1 Not tainted 6.11.0-syzkaller-11503-gc824deb1a897 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Workqueue: events nsim_dev_trap_report_work RIP: 0010:ipt_do_table+0x172/0x1860 Code: 84 24 e0 00 00 00 42 80 3c 28 00 74 15 48 89 df e8 b3 0d b2 f7 48 8b 54 24 18 48 8d 8c 24 60 01 00 00 48 89 9c 24 e8 00 00 00 <4d> 01 fc 4d 89 e7 49 8b 46 08 48 8d b0 30 01 00 00 48 85 c0 48 c7 RSP: 0018:ffffc90000006c60 EFLAGS: 00000246 RAX: 1ffff92000000de1 RBX: ffffc90000006f08 RCX: ffffc90000006dc0 RDX: 0000000000000003 RSI: 0000000000000000 RDI: ffffc90000006de0 RBP: ffffc90000006e48 R08: ffffc90000006ddf R09: 0000000000000000 R10: ffffc90000006dc0 R11: fffff52000000dbc R12: ffff8881a0f64000 R13: dffffc0000000000 R14: ffffc90000006f00 R15: 0000000000000140 FS: 0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffde000000 CR3: 000000000e734000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline] nf_hook_slow+0xc3/0x220 net/netfilter/core.c:626 nf_hook+0x2c4/0x450 include/linux/netfilter.h:269 __ip_local_out+0x3d9/0x4e0 net/ipv4/ip_output.c:119 ip_local_out+0x26/0x70 net/ipv4/ip_output.c:128 synproxy_send_client_synack+0x8b8/0xf30 net/netfilter/nf_synproxy_core.c:484 nft_synproxy_eval_v4+0x3ca/0x610 net/netfilter/nft_synproxy.c:59 nft_synproxy_do_eval+0x362/0xa60 net/netfilter/nft_synproxy.c:141 expr_call_ops_eval net/netfilter/nf_tables_core.c:240 [inline] nft_do_chain+0x4ad/0x1da0 net/netfilter/nf_tables_core.c:288 nft_do_chain_inet+0x418/0x6b0 net/netfilter/nft_chain_filter.c:161 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline] nf_hook_slow+0xc3/0x220 net/netfilter/core.c:626 nf_hook include/linux/netfilter.h:269 [inline] NF_HOOK+0x29e/0x450 include/linux/netfilter.h:312 NF_HOOK+0x3a4/0x450 include/linux/netfilter.h:314 __netif_receive_skb_one_core net/core/dev.c:5662 [inline] __netif_receive_skb+0x2bf/0x650 net/core/dev.c:5775 process_backlog+0x662/0x15b0 net/core/dev.c:6107 __napi_poll+0xcb/0x490 net/core/dev.c:6771 napi_poll net/core/dev.c:6840 [inline] net_rx_action+0x89b/0x1240 net/core/dev.c:6962 handle_softirqs+0x2c5/0x980 kernel/softirq.c:554 do_softirq+0x11b/0x1e0 kernel/softirq.c:455 __local_bh_enable_ip+0x1bb/0x200 kernel/softirq.c:382 spin_unlock_bh include/linux/spinlock.h:396 [inline] nsim_dev_trap_report drivers/net/netdevsim/dev.c:820 [inline] nsim_dev_trap_report_work+0x75d/0xaa0 drivers/net/netdevsim/dev.c:850 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa63/0x1850 kernel/workqueue.c:3310 worker_thread+0x870/0xd30 kernel/workqueue.c:3391 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244