rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5846/1:b..l rcu: (detected by 0, t=10503 jiffies, g=8013, q=1035 ncpus=2) task:syz.1.6 state:R running task stack:21992 pid:5846 ppid:5768 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x15ae/0x4660 kernel/sched/core.c:6700 preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6867 preempt_schedule+0xc0/0xd0 kernel/sched/core.c:6891 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45 __local_bh_enable_ip+0x14b/0x1c0 kernel/softirq.c:413 local_bh_enable include/linux/bottom_half.h:33 [inline] bpf_test_run+0x3dd/0x870 net/bpf/test_run.c:425 bpf_prog_test_run_skb+0xdbb/0x18f0 net/bpf/test_run.c:1089 bpf_prog_test_run+0x31f/0x390 kernel/bpf/syscall.c:4132 __sys_bpf+0x49d/0x890 kernel/bpf/syscall.c:5495 __do_sys_bpf kernel/bpf/syscall.c:5581 [inline] __se_sys_bpf kernel/bpf/syscall.c:5579 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5579 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: 0033:0x7fc7f659de99 RSP: 002b:00007fc7f7469028 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007fc7f6825fa0 RCX: 00007fc7f659de99 RDX: 0000000000000050 RSI: 0000200000000100 RDI: 000000000000000a RBP: 00007fc7f6633eaf R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fc7f6826038 R14: 00007fc7f6825fa0 R15: 00007ffec2755c58 rcu: rcu_preempt kthread starved for 9292 jiffies! g8013 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:26504 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: 5862 Comm: syz.3.8 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x60 kernel/kcov.c:212 Code: 00 0f 0b 0f 1f 80 00 00 00 00 f3 0f 1e fa 53 48 89 fb e8 13 00 00 00 48 8b 3d ec 87 05 0d 48 89 de 5b e9 23 a7 57 00 cc cc cc 0f 1e fa 48 8b 04 24 65 48 8b 0d c0 d2 7c 7e 65 8b 15 c1 d2 7c RSP: 0018:ffffc900001f02b8 EFLAGS: 00000246 RAX: 1ffff9200003e07e RBX: ffffc900001f03c8 RCX: ffffc900001f03e8 RDX: ffffc900001f03c8 RSI: ffff888018fb9e00 RDI: ffffc9000475fa00 RBP: ffffc9000475fa00 R08: ffff888018fb9e00 R09: 0000000000000003 R10: 0000000000000004 R11: 0000000000000100 R12: ffffc9000475fa00 R13: ffffc900001f03c8 R14: ffffc900001f03e8 R15: ffff888018fb9e00 FS: 00007f321d01e6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fc1b8d5da08 CR3: 00000000776d5000 CR4: 00000000003506e0 Call Trace: get_stack_info+0x1f/0x170 arch/x86/kernel/dumpstack_64.c:193 stack_access_ok arch/x86/kernel/unwind_orc.c:396 [inline] deref_stack_reg arch/x86/kernel/unwind_orc.c:403 [inline] unwind_next_frame+0x1517/0x2990 arch/x86/kernel/unwind_orc.c:585 arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4e/0x70 mm/kasan/common.c:53 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:329 kasan_slab_alloc include/linux/kasan.h:188 [inline] slab_post_alloc_hook+0x6a/0x4d0 mm/slab.h:767 slab_alloc_node mm/slub.c:3495 [inline] slab_alloc mm/slub.c:3503 [inline] __kmem_cache_alloc_lru mm/slub.c:3510 [inline] kmem_cache_alloc+0x17e/0x2c0 mm/slub.c:3519 dst_alloc+0x105/0x170 net/core/dst.c:90 ip6_dst_alloc net/ipv6/route.c:344 [inline] icmp6_dst_alloc+0x7c/0x400 net/ipv6/route.c:3320 ndisc_send_skb+0x422/0x1480 net/ipv6/ndisc.c:493 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:check_preemption_disabled+0x1/0x110 lib/smp_processor_id.c:13 Code: e9 6e ff ff ff cc cc cc cc f3 0f 1e fa 48 c7 c7 c0 f9 1c 8b 48 c7 c6 00 fa 1c 8b eb 0c 66 2e 0f 1f 84 00 00 00 00 00 66 90 55 <41> 57 41 56 53 48 83 ec 10 65 48 8b 04 25 28 00 00 00 48 89 44 24 RSP: 0018:ffffc9000475fab0 EFLAGS: 00000283 RAX: 0000000000000001 RBX: 0000000000000001 RCX: ffffffff81688636 RDX: 0000000000000000 RSI: ffffffff8b1cfa00 RDI: ffffffff8b1cf9c0 RBP: ffffc9000475fc00 R08: ffffffff8e8c6b2f R09: 1ffffffff1d18d65 R10: dffffc0000000000 R11: fffffbfff1d18d66 R12: ffffffff817b922d R13: dffffc0000000000 R14: ffffffff817b922d R15: 1ffff920008ebf68 rcu_dynticks_curr_cpu_in_eqs include/linux/context_tracking.h:122 [inline] rcu_is_watching+0x15/0xb0 kernel/rcu/tree.c:700 trace_lock_release include/trace/events/lock.h:69 [inline] lock_release+0xb5/0x8c0 kernel/locking/lockdep.c:5765 __raw_spin_unlock include/linux/spinlock_api_smp.h:141 [inline] _raw_spin_unlock+0x16/0x40 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] futex_wake+0x41d/0x4f0 kernel/futex/waitwake.c:183 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: 0033:0x7f321c19de99 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:00007f321d01e0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 00007f321c426278 RCX: 00007f321c19de99 RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f321c42627c RBP: 00007f321c426270 R08: 0000000000745b0f R09: 0000000000000000 R10: 0000000000000005 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f321c426308 R14: 00007ffefce49100 R15: 00007ffefce491e8