rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P14940/1:b..l P14946/2:b..l rcu: (detected by 1, t=10503 jiffies, g=62173, q=667408 ncpus=2) task:syz.0.4512 state:R running task stack:25904 pid:14946 tgid:14945 ppid:5221 flags:0x00000000 Call Trace: context_switch kernel/sched/core.c:5315 [inline] __schedule+0xef5/0x5750 kernel/sched/core.c:6675 preempt_schedule_common+0x44/0xc0 kernel/sched/core.c:6854 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12 __local_bh_enable_ip+0x107/0x120 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+0x887/0x4400 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+0x16d7/0x2530 net/ipv4/ip_output.c:236 __ip_finish_output net/ipv4/ip_output.c:314 [inline] __ip_finish_output+0x49e/0x950 net/ipv4/ip_output.c:296 ip_finish_output+0x31/0x310 net/ipv4/ip_output.c:324 NF_HOOK_COND include/linux/netfilter.h:303 [inline] ip_output+0x13b/0x2a0 net/ipv4/ip_output.c:434 dst_output include/net/dst.h:450 [inline] ip_local_out+0x33e/0x4a0 net/ipv4/ip_output.c:130 __ip_queue_xmit+0x747/0x1940 net/ipv4/ip_output.c:536 __tcp_transmit_skb+0x2a4c/0x3dc0 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+0x2471/0x5480 net/ipv4/tcp_output.c:4145 tcp_v4_connect+0x14f7/0x1b80 net/ipv4/tcp_ipv4.c:341 __inet_stream_connect+0x3c7/0x1020 net/ipv4/af_inet.c:679 tcp_sendmsg_fastopen+0x3d7/0x700 net/ipv4/tcp.c:1038 tcp_sendmsg_locked+0x2016/0x3750 net/ipv4/tcp.c:1090 tcp_sendmsg+0x2e/0x50 net/ipv4/tcp.c:1357 inet_sendmsg+0xb9/0x140 net/ipv4/af_inet.c:853 smc_sendmsg+0x221/0x520 net/smc/af_smc.c:2786 sock_sendmsg_nosec net/socket.c:729 [inline] __sock_sendmsg net/socket.c:744 [inline] ____sys_sendmsg+0xaaf/0xc90 net/socket.c:2602 ___sys_sendmsg+0x135/0x1e0 net/socket.c:2656 __sys_sendmsg+0x117/0x1f0 net/socket.c:2685 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6f3fd7dff9 RSP: 002b:00007f6f40b49038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f6f3ff35f80 RCX: 00007f6f3fd7dff9 RDX: 0000000020000080 RSI: 0000000020000840 RDI: 0000000000000003 RBP: 00007f6f3fdf0296 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f6f3ff35f80 R15: 00007ffe1b8723b8 task:syz.3.4510 state:R running task stack:27536 pid:14940 tgid:14937 ppid:5220 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5315 [inline] __schedule+0xef5/0x5750 kernel/sched/core.c:6675 preempt_schedule_common+0x44/0xc0 kernel/sched/core.c:6854 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] zap_pte_range mm/memory.c:1691 [inline] zap_pmd_range mm/memory.c:1739 [inline] zap_pud_range mm/memory.c:1768 [inline] zap_p4d_range mm/memory.c:1789 [inline] unmap_page_range+0xb01/0x3cf0 mm/memory.c:1810 unmap_single_vma+0x194/0x2b0 mm/memory.c:1856 unmap_vmas+0x22f/0x490 mm/memory.c:1900 exit_mmap+0x1c6/0xb30 mm/mmap.c:1864 __mmput+0x12a/0x480 kernel/fork.c:1347 mmput+0x62/0x70 kernel/fork.c:1369 exit_mm kernel/exit.c:571 [inline] do_exit+0x9bf/0x2d70 kernel/exit.c:926 do_group_exit+0xd3/0x2a0 kernel/exit.c:1088 get_signal+0x25fb/0x2770 kernel/signal.c:2917 arch_do_signal_or_restart+0x90/0x7e0 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x150/0x2a0 kernel/entry/common.c:218 do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f2d8a57dff9 RSP: 002b:00007f2d8b3b10e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007f2d8a735f88 RCX: 00007f2d8a57dff9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f2d8a735f88 RBP: 00007f2d8a735f80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f2d8a735f8c R13: 0000000000000000 R14: 00007ffca68d3050 R15: 00007ffca68d3138 rcu: rcu_preempt kthread starved for 10576 jiffies! g62173 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:27408 pid:17 tgid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5315 [inline] __schedule+0xef5/0x5750 kernel/sched/core.c:6675 __schedule_loop kernel/sched/core.c:6752 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6767 schedule_timeout+0x136/0x2a0 kernel/time/timer.c:2615 rcu_gp_fqs_loop+0x1eb/0xb00 kernel/rcu/tree.c:2045 rcu_gp_kthread+0x271/0x380 kernel/rcu/tree.c:2247 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 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: 941 Comm: kworker/0:2 Not tainted 6.11.0-syzkaller-11728-gad46e8f95e93 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Workqueue: events_power_efficient gc_worker RIP: 0010:__lock_acquire+0xbc2/0x3ce0 kernel/locking/lockdep.c:5194 Code: ff df 48 c1 ea 03 0f b6 14 02 48 c7 c0 54 5a 5f 90 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 d3 30 00 00 44 8b 1d 52 5b f5 0e <45> 85 db 75 40 44 8b 54 24 08 45 85 d2 0f 85 65 08 00 00 4c 89 ef RSP: 0018:ffffc90000007828 EFLAGS: 00000046 RAX: 0000000000000007 RBX: e3a7f52acf58201d RCX: ffffffff816a0198 RDX: 0000000000000000 RSI: 0000000000000008 RDI: 000000003a7f52ae RBP: 0000000000000000 R08: 0000000000000000 R09: fffffbfff2dc4588 R10: ffffffff96e22c47 R11: 0000000000000000 R12: dffffc0000000000 R13: ffff888025fb4780 R14: 0000000000000002 R15: ffff888025fb3c00 FS: 0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b31f16ff8 CR3: 000000000df7c000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5822 rcu_lock_acquire include/linux/rcupdate.h:337 [inline] rcu_read_lock include/linux/rcupdate.h:849 [inline] nf_hook.constprop.0+0xaa/0x750 include/linux/netfilter.h:238 NF_HOOK include/linux/netfilter.h:312 [inline] ip_local_deliver+0x169/0x1f0 net/ipv4/ip_input.c:254 dst_input include/net/dst.h:460 [inline] ip_rcv_finish net/ipv4/ip_input.c:449 [inline] NF_HOOK include/linux/netfilter.h:314 [inline] NF_HOOK include/linux/netfilter.h:308 [inline] ip_rcv+0x2c3/0x5d0 net/ipv4/ip_input.c:569 __netif_receive_skb_one_core+0x199/0x1e0 net/core/dev.c:5662 __netif_receive_skb+0x1d/0x160 net/core/dev.c:5775 process_backlog+0x443/0x15f0 net/core/dev.c:6107 __napi_poll.constprop.0+0xb7/0x550 net/core/dev.c:6771 napi_poll net/core/dev.c:6840 [inline] net_rx_action+0xa92/0x1010 net/core/dev.c:6962 handle_softirqs+0x213/0x8f0 kernel/softirq.c:554 __do_softirq kernel/softirq.c:588 [inline] invoke_softirq kernel/softirq.c:428 [inline] __irq_exit_rcu kernel/softirq.c:637 [inline] irq_exit_rcu+0xbb/0x120 kernel/softirq.c:649 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1037 [inline] sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1037 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__seqprop_spinlock_sequence include/linux/seqlock.h:227 [inline] RIP: 0010:nf_conntrack_get_ht include/net/netfilter/nf_conntrack.h:345 [inline] RIP: 0010:gc_worker+0x2e1/0x1760 net/netfilter/nf_conntrack_core.c:1534 Code: 00 00 48 c7 c7 08 d1 5f 90 e8 6b 96 28 f8 9c 5b 81 e3 00 02 00 00 31 ff 48 89 de e8 59 79 4b f8 48 85 db 58 0f 85 3d 10 00 00 da 76 4b f8 eb 07 e8 d3 76 4b f8 f3 90 44 8b 35 3a 32 1e 07 44 RSP: 0018:ffffc90004107bc8 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff8941aa6a RDX: ffff888025fb3c00 RSI: ffffffff8941aa79 RDI: 0000000000000007 RBP: ffff88802e200000 R08: 0000000000000007 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 000000000000d85a R13: dffffc0000000000 R14: 000000000001b0b3 R15: 0000000000040000 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3229 process_scheduled_works kernel/workqueue.c:3310 [inline] worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244