rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-...!: (10382 ticks this GP) idle=cd54/1/0x4000000000000000 softirq=11089/11137 fqs=24 rcu: (t=10500 jiffies g=10313 q=1112 ncpus=2) rcu: rcu_preempt kthread starved for 7352 jiffies! g10313 f0x0 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:27752 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5380 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699 schedule+0xbd/0x170 kernel/sched/core.c:6773 schedule_timeout+0x160/0x280 kernel/time/timer.c:2168 rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667 rcu_gp_kthread+0x99/0x380 kernel/rcu/tree.c:1866 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 5773 Comm: syz-executor Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:148 Code: cc cc cc cc cc cc cc f3 0f 1e fa 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 66 90 0f 00 2d a3 14 39 00 f3 0f 1e fa fb f4 cc cc cc cc cc cc cc cc cc cc cc cc 66 0f 1f 00 55 41 57 41 56 RSP: 0018:ffffc900044af8b8 EFLAGS: 000002d3 RAX: ffffffff813a13aa RBX: 0000000000000003 RCX: ffff888077d9da00 RDX: 0000000000000000 RSI: ffffffff8aaabce0 RDI: ffffffff8afc6f80 RBP: ffffc900044af990 R08: ffffffff90da95c7 R09: 1ffffffff21b52b8 R10: dffffc0000000000 R11: fffffbfff21b52b9 R12: dffffc0000000000 R13: 0000000000000200 R14: 0000000000000003 R15: 1ffff92000895f1c FS: 000055555bb0d500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000564f6212be30 CR3: 0000000075e41000 CR4: 00000000003506f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline] kvm_wait+0x22f/0x290 arch/x86/kernel/kvm.c:1058 pv_wait arch/x86/include/asm/paravirt.h:598 [inline] pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:470 [inline] __pv_queued_spin_lock_slowpath+0x61a/0x9d0 kernel/locking/qspinlock.c:511 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:586 [inline] queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline] queued_spin_lock include/asm-generic/qspinlock.h:114 [inline] do_raw_spin_lock+0x24e/0x2c0 kernel/locking/spinlock_debug.c:115 spin_lock_bh include/linux/spinlock.h:356 [inline] lock_sock_nested+0x6a/0x100 net/core/sock.c:3538 lock_sock include/net/sock.h:1767 [inline] tcp_sendmsg+0x21/0x50 net/ipv4/tcp.c:1343 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] sock_write_iter+0x2bb/0x3f0 net/socket.c:1160 call_write_iter include/linux/fs.h:2018 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x43b/0x940 fs/read_write.c:584 ksys_write+0x147/0x250 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f1c9858e1c0 Code: 40 00 48 c7 c2 a8 ff ff ff f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 80 3d a1 d3 22 00 00 74 17 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 58 c3 0f 1f 80 00 00 00 00 48 83 ec 28 48 89 RSP: 002b:00007fffdf73aa18 EFLAGS: 00000202 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000001299dfeac0 RCX: 00007f1c9858e1c0 RDX: 000000000000bc40 RSI: 00007f1c951f43c0 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000007 R09: 00000000005ffde8 R10: 330118c009ff4b16 R11: 0000000000000202 R12: 000000000000bc40 R13: 000055555bb24ae0 R14: 00007fffdf73af20 R15: 00007f1c951f43c0 CPU: 1 PID: 5897 Comm: syz.3.7 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:get_current arch/x86/include/asm/current.h:41 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x8/0x60 kernel/kcov.c:215 Code: 00 00 f3 0f 1e fa 53 48 89 fb e8 13 00 00 00 48 8b 3d 5c 05 c5 0c 48 89 de 5b e9 43 9d 56 00 cc cc cc f3 0f 1e fa 48 8b 04 24 <65> 48 8b 0d f0 24 7e 7e 65 8b 15 f1 24 7e 7e 81 e2 00 01 ff 00 74 RSP: 0018:ffffc900001ef6f8 EFLAGS: 00000286 RAX: ffffffff8869daf1 RBX: ffff8881417e8080 RCX: ffff88802b370000 RDX: 0000000000000100 RSI: ffff8881417e8000 RDI: ffff88805ce70a00 RBP: 1ffff1100b9ce140 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff5200003defc R12: 0000000000000000 R13: ffff8881417e8000 R14: ffff88805ce70a00 R15: dffffc0000000000 FS: 00007f5add7086c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f07647b6418 CR3: 0000000025862000 CR4: 00000000003506e0 Call Trace: dev_queue_xmit_nit+0x21/0xbb0 net/core/dev.c:2315 xmit_one net/core/dev.c:3615 [inline] dev_hard_start_xmit+0x148/0x740 net/core/dev.c:3635 sch_direct_xmit+0x252/0x4a0 net/sched/sch_generic.c:345 __dev_xmit_skb net/core/dev.c:3856 [inline] __dev_queue_xmit+0x173e/0x35a0 net/core/dev.c:4391 neigh_output include/net/neighbour.h:543 [inline] ip_finish_output2+0xd21/0x11d0 net/ipv4/ip_output.c:235 dst_output include/net/dst.h:467 [inline] ip_local_out net/ipv4/ip_output.c:129 [inline] __ip_queue_xmit+0x10aa/0x1a10 net/ipv4/ip_output.c:535 __tcp_transmit_skb+0x1c97/0x32a0 net/ipv4/tcp_output.c:1422 tcp_ack_snd_check net/ipv4/tcp_input.c:5728 [inline] tcp_rcv_established+0xb00/0x1cf0 net/ipv4/tcp_input.c:6174 tcp_v4_do_rcv+0x4ed/0xb80 net/ipv4/tcp_ipv4.c:1734 tcp_v4_rcv+0x2334/0x2a50 net/ipv4/tcp_ipv4.c:2166 ip_protocol_deliver_rcu+0x20e/0x3f0 net/ipv4/ip_input.c:205 ip_local_deliver_finish+0x2ca/0x510 net/ipv4/ip_input.c:233 NF_HOOK+0x303/0x390 include/linux/netfilter.h:304 dst_input include/net/dst.h:477 [inline] ip_sublist_rcv_finish net/ipv4/ip_input.c:580 [inline] ip_list_rcv_finish net/ipv4/ip_input.c:631 [inline] ip_sublist_rcv+0xa38/0xd20 net/ipv4/ip_input.c:639 ip_list_rcv+0x3e3/0x430 net/ipv4/ip_input.c:674 __netif_receive_skb_list_ptype net/core/dev.c:5651 [inline] __netif_receive_skb_list_core+0x578/0x740 net/core/dev.c:5699 __netif_receive_skb_list net/core/dev.c:5751 [inline] netif_receive_skb_list_internal+0x91b/0xc60 net/core/dev.c:5842 gro_normal_list include/net/gro.h:451 [inline] napi_complete_done+0x32a/0x810 net/core/dev.c:6182 virtqueue_napi_complete drivers/net/virtio_net.c:450 [inline] virtnet_poll+0xa44/0x1180 drivers/net/virtio_net.c:2236 __napi_poll+0xc0/0x460 net/core/dev.c:6612 napi_poll net/core/dev.c:6679 [inline] net_rx_action+0x5ea/0xbf0 net/core/dev.c:6815 handle_softirqs+0x280/0x820 kernel/softirq.c:578 __do_softirq kernel/softirq.c:612 [inline] invoke_softirq kernel/softirq.c:452 [inline] __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline] sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:__sanitizer_cov_trace_pc+0x5c/0x60 kernel/kcov.c:234 Code: f8 15 00 00 83 fa 02 75 21 48 8b 91 00 16 00 00 48 8b 32 48 8d 7e 01 8b 89 fc 15 00 00 48 39 cf 73 08 48 89 3a 48 89 44 f2 08 0f 1f 00 f3 0f 1e fa 48 8b 04 24 65 48 8b 15 90 24 7e 7e 65 8b RSP: 0018:ffffc90004a8f2f0 EFLAGS: 00000287 RAX: ffffffff813ac02f RBX: ffffc90004a88001 RCX: 0000000000080000 RDX: ffffc9000d12b000 RSI: 000000000002e347 RDI: 000000000002e348 RBP: ffffc90004a8fd00 R08: ffff88802b370000 R09: 0000000000000003 R10: 0000000000000004 R11: 0000000000000002 R12: ffffc90004a8f3c8 R13: dffffc0000000000 R14: ffffc90004a8fd40 R15: ffffc90004a8f3d8 unwind_next_frame+0x1cef/0x2970 arch/x86/kernel/unwind_orc.c:665 arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:45 __kasan_record_aux_stack+0xaf/0xc0 mm/kasan/generic.c:492 __call_rcu_common kernel/rcu/tree.c:2721 [inline] call_rcu+0x158/0x930 kernel/rcu/tree.c:2837 context_switch kernel/sched/core.c:5383 [inline] __schedule+0x14da/0x44d0 kernel/sched/core.c:6699 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7009 irqentry_exit+0x67/0x70 kernel/entry/common.c:438 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:d_alloc_pseudo+0x0/0x70 fs/dcache.c:1904 Code: 89 f0 5b 41 5c 41 5e 41 5f c3 44 89 f1 80 e1 07 80 c1 03 38 c1 7c 9f 4c 89 f7 e8 db f2 ea ff eb 95 66 0f 1f 84 00 00 00 00 00 <66> 0f 1f 00 41 56 53 48 89 f3 49 89 fe e8 ee 84 93 ff 4c 89 f7 48 RSP: 0018:ffffc90004a8fc18 EFLAGS: 00000246 RAX: 000000000000000c RBX: 1ffff92000951f88 RCX: 000000008ab2e304 RDX: ffffc9000d12b000 RSI: ffffc90004a8fc60 RDI: ffff88801aeda000 RBP: ffffc90004a8fcf0 R08: ffffffff8ab2d8c0 R09: 1ffff11003f9ad51 R10: dffffc0000000000 R11: ffffed1003f9ad52 R12: ffff88801ae4b520 R13: dffffc0000000000 R14: ffff88801ae4b528 R15: 1ffff110035c96a5 alloc_file_pseudo+0xcc/0x200 fs/file_table.c:329 __anon_inode_getfile fs/anon_inodes.c:122 [inline] anon_inode_getfile+0xc5/0x1a0 fs/anon_inodes.c:160 __do_sys_perf_event_open kernel/events/core.c:12855 [inline] __se_sys_perf_event_open+0xeb5/0x1c20 kernel/events/core.c:12567 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f5adc78f749 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f5add708038 EFLAGS: 00000246 ORIG_RAX: 000000000000012a RAX: ffffffffffffffda RBX: 00007f5adc9e5fa0 RCX: 00007f5adc78f749 RDX: ffffffffffffffff RSI: 0000000000000000 RDI: 0000200000000040 RBP: 00007f5adc813f91 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000 R13: 00007f5adc9e6038 R14: 00007f5adc9e5fa0 R15: 00007ffe1b321618