rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (1 GPs behind) idle=d10c/1/0x4000000000000000 softirq=19470/19471 fqs=2 rcu: (t=10501 jiffies g=23885 q=406 ncpus=2) rcu: rcu_preempt kthread starved for 10498 jiffies! g23885 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 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:27848 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x15ae/0x4660 kernel/sched/core.c:6700 schedule+0xbd/0x170 kernel/sched/core.c:6774 schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168 rcu_gp_fqs_loop+0x30d/0x1590 kernel/rcu/tree.c:1667 rcu_gp_kthread+0x9d/0x3b0 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 7770 Comm: syz.0.590 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:434 [inline] RIP: 0010:__pv_queued_spin_lock_slowpath+0x52e/0x9c0 kernel/locking/qspinlock.c:511 Code: 8b 44 24 18 c6 00 00 48 8b 44 24 10 42 0f b6 04 28 84 c0 0f 85 1b 01 00 00 48 8d 43 01 c6 00 01 41 bc 00 80 ff ff eb 07 f3 90 <41> ff c4 74 47 43 0f b6 04 2e 84 c0 75 2b 80 3b 00 75 eb 48 89 df RSP: 0018:ffffc9000334f960 EFLAGS: 00000206 RAX: 0000000000000000 RBX: ffffc90000a26c08 RCX: ffff88802d3f0000 RDX: 0000000000000000 RSI: ffffffff8acacb60 RDI: ffffffff8b1c7be0 RBP: ffffc9000334fa50 R08: ffffffff911bc5ff R09: 1ffffffff22378bf R10: dffffc0000000000 R11: fffffbfff22378c0 R12: 00000000ffffe20d R13: dffffc0000000000 R14: 1ffff92000144d81 R15: ffff8880b8f30001 FS: 000055559106d500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c2d4aa5 CR3: 0000000023e26000 CR4: 00000000003506e0 DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: 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+0x23e/0x2b0 kernel/locking/spinlock_debug.c:115 spin_lock include/linux/spinlock.h:351 [inline] futex_unqueue+0x4e/0xf0 kernel/futex/core.c:597 futex_wait+0x1f1/0x5c0 kernel/futex/waitwake.c:660 do_futex+0x2ff/0x3e0 kernel/futex/syscalls.c:134 __do_sys_futex kernel/futex/syscalls.c:211 [inline] __se_sys_futex+0x3a9/0x440 kernel/futex/syscalls.c:192 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f45d9d9ce59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fff35865658 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 000000000002c128 RCX: 00007f45d9d9ce59 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f45da015fac RBP: 0000000000000032 R08: 0000000000745d1e R09: 0000000000000000 R10: 00007fff35865760 R11: 0000000000000246 R12: 00007fff35865780 R13: 00007f45da015fac R14: 000000000002c15a R15: 00007fff35865760 CPU: 0 PID: 7771 Comm: syz.0.590 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:should_resched arch/x86/include/asm/preempt.h:104 [inline] RIP: 0010:__local_bh_enable_ip+0x142/0x1c0 kernel/softirq.c:413 Code: 8a e8 32 a2 31 09 65 66 8b 05 2a 6c b1 7e 66 85 c0 75 54 bf 01 00 00 00 e8 2b 1d 0a 00 e8 c6 07 3b 00 fb 65 8b 05 f6 6b b1 7e <85> c0 75 05 e8 c5 50 ae ff 48 c7 04 24 0e 36 e0 45 4b c7 04 37 00 RSP: 0018:ffffc900000074a0 EFLAGS: 00000286 RAX: 0000000000000101 RBX: 0000000000000200 RCX: d10919263a555f00 RDX: dffffc0000000000 RSI: ffffffff8acacb60 RDI: ffffffff8b1c7be0 RBP: ffffc90000007530 R08: ffffffff911bc5ff R09: 1ffffffff22378bf R10: dffffc0000000000 R11: fffffbfff22378c0 R12: ffffffff895086fb R13: dffffc0000000000 R14: dffffc0000000000 R15: 1ffff92000000e94 FS: 00007f45daca76c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000100000000 CR3: 0000000023e26000 CR4: 00000000003506f0 DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: local_bh_enable include/linux/bottom_half.h:33 [inline] ip6t_do_table+0x13c4/0x1570 net/ipv6/netfilter/ip6_tables.c:375 ip6t_mangle_out net/ipv6/netfilter/ip6table_mangle.c:49 [inline] ip6table_mangle_hook+0x270/0x700 net/ipv6/netfilter/ip6table_mangle.c:71 nf_hook_entry_hookfn include/linux/netfilter.h:144 [inline] nf_hook_slow+0xbd/0x200 net/netfilter/core.c:626 nf_hook include/linux/netfilter.h:259 [inline] NF_HOOK include/linux/netfilter.h:302 [inline] ndisc_send_skb+0x1331/0x1480 net/ipv6/ndisc.c:513 addrconf_rs_timer+0x36b/0x640 net/ipv6/addrconf.c:4029 call_timer_fn+0x189/0x540 kernel/time/timer.c:1701 expire_timers kernel/time/timer.c:1752 [inline] __run_timers+0x570/0x810 kernel/time/timer.c:2023 run_timer_softirq+0x67/0xf0 kernel/time/timer.c:2036 handle_softirqs+0x27d/0x820 kernel/softirq.c:578 __do_softirq kernel/softirq.c:612 [inline] invoke_softirq kernel/softirq.c:452 [inline] __irq_exit_rcu+0xd3/0x190 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+0x3b/0x60 kernel/kcov.c:219 Code: 8b 15 e1 d2 7c 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 1c 16 00 00 00 74 2c 8b 91 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 RSP: 0018:ffffc9000341fb08 EFLAGS: 00000246 RAX: ffffffff8a733c49 RBX: ffffc9000334fc68 RCX: ffff88807e3f8000 RDX: 0000000000000002 RSI: 0000000000016c18 RDI: 0000000000016c19 RBP: ffffc90000a26c48 R08: ffff88802d3f002b R09: 1ffff11005a7e005 R10: dffffc0000000000 R11: ffffed1005a7e006 R12: ffffc90000a26c48 R13: ffffc90000a26c50 R14: ffffc9000334fc68 R15: dffffc0000000000 plist_check_list+0x229/0x240 lib/plist.c:49 plist_check_head lib/plist.c:60 [inline] plist_del+0x69/0x3c0 lib/plist.c:114 __futex_unqueue+0xeb/0x150 kernel/futex/core.c:518 futex_wake_mark+0xec/0x150 kernel/futex/waitwake.c:123 futex_wake+0x32f/0x4f0 kernel/futex/waitwake.c:177 do_futex+0x35d/0x3e0 kernel/futex/syscalls.c:139 __do_sys_futex kernel/futex/syscalls.c:211 [inline] __se_sys_futex+0x3a9/0x440 kernel/futex/syscalls.c:192 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f45d9d9ce59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f45daca70e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 00007f45da015fa8 RCX: 00007f45d9d9ce59 RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f45da015fac RBP: 00007f45da015fa0 R08: 0000000000745d1e R09: 0000000000000000 R10: 0000000000000006 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f45da016038 R14: 00007fff35865410 R15: 00007fff358654f8