rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=4954/1/0x4000000000000000 softirq=31242/31249 fqs=0 rcu: (detected by 1, t=10502 jiffies, g=26717, q=588 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 9791 Comm: syz.4.1138 Not tainted 6.15.0-rc3-syzkaller-00150-g0a7bc4d6b04b #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:26 [inline] RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:109 [inline] RIP: 0010:arch_irqs_disabled arch/x86/include/asm/irqflags.h:151 [inline] RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x8f/0x110 kernel/locking/spinlock.c:194 Code: c7 18 48 8b 75 08 e8 30 12 46 f6 4c 89 f7 e8 58 a9 46 f6 f7 c3 00 02 00 00 74 05 e8 3b 30 6f f6 48 c7 44 24 20 00 00 00 00 9c <8f> 44 24 20 f6 44 24 21 02 75 4f f7 c3 00 02 00 00 74 01 fb bf 01 RSP: 0018:ffffc90000007c78 EFLAGS: 00000046 RAX: 0000000000000001 RBX: 0000000000000802 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffffff99a37438 RBP: ffffc90000007d08 R08: ffffffff99a3743b R09: 1ffffffff3346e87 R10: dffffc0000000000 R11: fffffbfff3346e88 R12: dffffc0000000000 R13: dffffc0000000000 R14: ffffffff99a37438 R15: 1ffff92000000f90 FS: 0000555590d05500(0000) GS:ffff8881260cf000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c26f440 CR3: 0000000055462000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: debug_hrtimer_deactivate kernel/time/hrtimer.c:450 [inline] debug_deactivate+0x1d/0x200 kernel/time/hrtimer.c:490 __run_hrtimer kernel/time/hrtimer.c:1729 [inline] __hrtimer_run_queues+0x2b0/0xc60 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline] __sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1055 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:seqcount_lockdep_reader_access+0x17e/0x1c0 include/linux/seqlock.h:75 Code: 00 4d 85 e4 75 16 e8 01 4a 11 00 eb 15 e8 fa 49 11 00 e8 05 14 a7 09 4d 85 e4 74 ea e8 eb 49 11 00 fb 48 c7 04 24 0e 36 e0 45 <4b> c7 04 3e 00 00 00 00 66 43 c7 44 3e 09 00 00 43 c6 44 3e 0b 00 RSP: 0018:ffffc9001b32fd00 EFLAGS: 00000293 RAX: ffffffff81ae7395 RBX: 0000000000000000 RCX: ffff88807ad48000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc9001b32fdb8 R08: ffffffff8f7ec877 R09: 1ffffffff1efd90e R10: dffffc0000000000 R11: fffffbfff1efd90f R12: 0000000000000200 R13: 0000000002faf080 R14: 1ffff92003665fa0 R15: dffffc0000000000 ktime_get+0x3e/0x1f0 kernel/time/timekeeping.c:750 futex_init_timeout kernel/futex/syscalls.c:154 [inline] __do_sys_futex kernel/futex/syscalls.c:173 [inline] __se_sys_futex+0x2b1/0x400 kernel/futex/syscalls.c:160 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fd516d8e969 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:00007ffee5a36458 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 00000000000356fa RCX: 00007fd516d8e969 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fd516fb5fac RBP: 0000000000000032 R08: 7fffffffffffffff R09: 00000007e5a3674f R10: 00007ffee5a36550 R11: 0000000000000246 R12: 00007fd516fb5fac R13: 00007ffee5a36550 R14: 000000000003572c R15: 00007ffee5a36570 rcu: rcu_preempt kthread starved for 10502 jiffies! g26717 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:26872 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x16e2/0x4cd0 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0x165/0x360 kernel/sched/core.c:6860 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2046 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2248 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 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: 5819 Comm: syz-executor Not tainted 6.15.0-rc3-syzkaller-00150-g0a7bc4d6b04b #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline] RIP: 0010:smp_call_function_many_cond+0xe69/0x11c0 kernel/smp.c:885 Code: 00 45 8b 2f 44 89 ee 83 e6 01 31 ff e8 20 6d 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 cb 68 0b 00 eb 37 f3 90 <43> 0f b6 04 2c 84 c0 75 10 41 f7 07 01 00 00 00 74 1e e8 b0 68 0b RSP: 0018:ffffc90003f3f4e0 EFLAGS: 00000293 RAX: ffffffff81b454d0 RBX: ffff8880b893ad40 RCX: ffff888077bb9e00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90003f3f640 R08: ffffffff8f7ec877 R09: 1ffffffff1efd90e R10: dffffc0000000000 R11: fffffbfff1efd90f R12: 1ffff11017108245 R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8880b8841228 FS: 0000000000000000(0000) GS:ffff8881261cf000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f89e2ee56c0 CR3: 0000000064326000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1052 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1275 [inline] flush_tlb_mm_range+0x6ae/0x12b0 arch/x86/mm/tlb.c:1365 tlb_flush arch/x86/include/asm/tlb.h:23 [inline] tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:480 [inline] tlb_flush_mmu+0x1a7/0x680 mm/mmu_gather.c:403 tlb_finish_mmu+0xc3/0x1d0 mm/mmu_gather.c:496 exit_mmap+0x474/0xba0 mm/mmap.c:1297 __mmput+0x118/0x420 kernel/fork.c:1379 exit_mm+0x1da/0x2c0 kernel/exit.c:589 do_exit+0x859/0x2550 kernel/exit.c:940 do_group_exit+0x21c/0x2d0 kernel/exit.c:1102 get_signal+0x125e/0x1310 kernel/signal.c:3034 arch_do_signal_or_restart+0x95/0x780 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:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x8b/0x120 kernel/entry/common.c:218 do_syscall_64+0x103/0x210 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f1f02d84b93 Code: Unable to access opcode bytes at 0x7f1f02d84b69. RSP: 002b:00007fffb8d821b8 EFLAGS: 00000202 ORIG_RAX: 000000000000003d RAX: fffffffffffffe00 RBX: 00000000000016c0 RCX: 00007f1f02d84b93 RDX: 0000000040000000 RSI: 00007fffb8d821cc RDI: 00000000ffffffff RBP: 00007fffb8d821cc R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000008 R13: 0000000000000003 R14: 0000000000000009 R15: 0000000000000000