rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (0 ticks this GP) idle=9924/1/0x4000000000000000 softirq=136063/136063 fqs=4 rcu: (detected by 1, t=10502 jiffies, g=116917, q=328 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 19994 Comm: syz.6.2510 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x70 kernel/kcov.c:210 Code: 89 fb e8 23 00 00 00 48 8b 3d a4 ba 1e 0c 48 89 de 5b e9 03 5e 59 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 48 8b 04 24 65 48 8b 0c 25 08 80 c3 92 65 8b 15 a8 c4 RSP: 0018:ffffc90000007ce8 EFLAGS: 00000086 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000001 RDX: 0000000000010000 RSI: ffff888027f0d340 RDI: ffff8880b8627bd0 RBP: ffffc90000007e90 R08: ffffffff8fc3f337 R09: 1ffffffff1f87e66 R10: dffffc0000000000 R11: fffffbfff1f87e67 R12: ffff888027f0d340 R13: dffffc0000000000 R14: ffff8880b8627bd0 R15: ffff8880b8627b80 FS: 00007fe5147bd6c0(0000) GS:ffff8881259e8000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c3e963f CR3: 000000005c7be000 CR4: 00000000003526f0 Call Trace: timerqueue_add+0x27/0x200 lib/timerqueue.c:36 __run_hrtimer kernel/time/hrtimer.c:1794 [inline] __hrtimer_run_queues+0x656/0xc60 kernel/time/hrtimer.c:1841 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline] __sysvec_apic_timer_interrupt+0x10b/0x410 arch/x86/kernel/apic/apic.c:1058 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1052 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:finish_task_switch+0x26b/0x950 kernel/sched/core.c:5228 Code: 0f 84 3c 01 00 00 48 85 db 0f 85 63 01 00 00 0f 1f 44 00 00 4c 8b 75 d0 4c 89 e7 e8 ff 81 f4 09 e8 7a 4c 36 00 fb 4c 8b 65 c0 <49> 8d bc 24 58 16 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0 RSP: 0018:ffffc9000b607758 EFLAGS: 00000282 RAX: 1227570112ea9100 RBX: 0000000000000000 RCX: 1227570112ea9100 RDX: 0000000000000000 RSI: ffffffff8dbbd648 RDI: ffffffff8c036f00 RBP: ffffc9000b6077b0 R08: ffffffff8fc3f337 R09: 1ffffffff1f87e66 R10: dffffc0000000000 R11: fffffbfff1f87e67 R12: ffff888025915ac0 R13: dffffc0000000000 R14: ffff888033988000 R15: ffff8880b863ab58 context_switch kernel/sched/core.c:5363 [inline] __schedule+0x17a0/0x4cc0 kernel/sched/core.c:6964 __schedule_loop kernel/sched/core.c:7046 [inline] schedule+0x165/0x360 kernel/sched/core.c:7061 futex_do_wait kernel/futex/waitwake.c:358 [inline] __futex_wait+0x1c3/0x3e0 kernel/futex/waitwake.c:687 futex_wait+0x104/0x360 kernel/futex/waitwake.c:715 do_futex+0x333/0x420 kernel/futex/syscalls.c:102 __do_sys_futex kernel/futex/syscalls.c:179 [inline] __se_sys_futex+0x36f/0x400 kernel/futex/syscalls.c:160 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe51398eba9 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:00007fe5147bd0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 00007fe513bd5fa8 RCX: 00007fe51398eba9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fe513bd5fa8 RBP: 00007fe513bd5fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fe513bd6038 R14: 00007ffd33fb7b80 R15: 00007ffd33fb7c68 rcu: rcu_preempt kthread starved for 10494 jiffies! g116917 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:27256 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5360 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6964 __schedule_loop kernel/sched/core.c:7046 [inline] schedule+0x165/0x360 kernel/sched/core.c:7061 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 UID: 0 PID: 19995 Comm: syz.7.2509 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0xd33/0x12d0 kernel/smp.c:877 Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 16 7c 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 c1 77 0b 00 eb 38 f3 90 <42> 0f b6 04 2b 84 c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 a5 77 RSP: 0018:ffffc90010607540 EFLAGS: 00000246 RAX: ffffffff81b443cb RBX: 1ffff110170c8355 RCX: 0000000000080000 RDX: ffffc9000c0fb000 RSI: 000000000007ffff RDI: 0000000000080000 RBP: ffffc900106076c0 R08: ffffffff8fc3f337 R09: 1ffffffff1f87e66 R10: dffffc0000000000 R11: fffffbfff1f87e67 R12: ffff8880b8641aa8 R13: dffffc0000000000 R14: ffff8880b873b1c0 R15: 0000000000000000 FS: 00007fec3ca4a6c0(0000) GS:ffff888125ae8000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fec319ffe00 CR3: 000000007fcca000 CR4: 00000000003526f0 DR0: 0000000002000000 DR1: 0000000000000003 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1044 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline] flush_tlb_mm_range+0x6b1/0x12d0 arch/x86/mm/tlb.c:1451 tlb_flush arch/x86/include/asm/tlb.h:23 [inline] tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:490 [inline] tlb_flush_mmu+0x1a7/0x680 mm/mmu_gather.c:403 tlb_finish_mmu+0xc3/0x1d0 mm/mmu_gather.c:497 vms_clear_ptes+0x42c/0x540 mm/vma.c:1235 vms_complete_munmap_vmas+0x206/0x8a0 mm/vma.c:1277 do_vmi_align_munmap+0x364/0x440 mm/vma.c:1536 do_vmi_munmap+0x253/0x2e0 mm/vma.c:1584 __vm_munmap+0x207/0x380 mm/vma.c:3156 __do_sys_munmap mm/mmap.c:1080 [inline] __se_sys_munmap mm/mmap.c:1077 [inline] __x64_sys_munmap+0x60/0x70 mm/mmap.c:1077 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fec3bb8ec37 Code: 00 00 00 48 c7 c2 a8 ff ff ff f7 d8 64 89 02 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 0b 00 00 00 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:00007fec3ca49e18 EFLAGS: 00000246 ORIG_RAX: 000000000000000b RAX: ffffffffffffffda RBX: 0000000000200000 RCX: 00007fec3bb8ec37 RDX: 0000000000000000 RSI: 0000000008400000 RDI: 00007fec31800000 RBP: 0000000000000000 R08: 0000000000000000 R09: 000000000001f78d R10: 00002000000003c2 R11: 0000000000000246 R12: 0000000000000003 R13: 00007fec3ca49ef0 R14: 00007fec3ca49eb0 R15: 00007fec31800000