rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=8ab/1/0x4000000000000000 softirq=49676/49677 fqs=9 (detected by 1, t=10505 jiffies, g=81769, q=68) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 15379 Comm: syz-executor.3 Not tainted 5.15.131-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/04/2023 RIP: 0010:__lock_acquire+0xd22/0x1ff0 kernel/locking/lockdep.c:4984 Code: df 48 63 c5 48 8b 6c 24 18 48 0f a3 05 a7 f1 5a 0e 0f 83 4c 08 00 00 48 81 c5 e0 0a 00 00 49 89 ee 49 c1 ee 03 41 80 3c 3e 00 <74> 12 48 89 ef e8 a4 2e 67 00 48 bf 00 00 00 00 00 fc ff df 31 c0 RSP: 0018:ffffc90000007a60 EFLAGS: 00000046 RAX: 000000000000108b RBX: ffff8880744e28b0 RCX: ffffffff81628f3f RDX: 0000000000000000 RSI: 0000000000000008 RDI: dffffc0000000000 RBP: ffff8880744e28a0 R08: dffffc0000000000 R09: fffffbfff1f7b063 R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000000 R13: ffff8880744e28a8 R14: 1ffff1100e89c514 R15: ffff8880744e28d0 FS: 0000555555e2c480(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fafb0f7a6be CR3: 000000003d875000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5622 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:363 [inline] advance_sched+0x47/0x940 net/sched/sch_taprio.c:716 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x598/0xcf0 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1085 [inline] __sysvec_apic_timer_interrupt+0x139/0x470 arch/x86/kernel/apic/apic.c:1102 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1096 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:finish_lock_switch+0x91/0x100 kernel/sched/core.c:4781 Code: 45 31 c9 68 07 61 59 81 e8 fc 1a 09 00 48 83 c4 08 4c 89 ff e8 b0 da fe ff eb 32 4c 89 ff e8 c6 c7 cc 08 e8 61 33 2d 00 fb 5b <41> 5c 41 5d 41 5e 41 5f c3 44 89 f1 80 e1 07 80 c1 03 38 c1 7c 87 RSP: 0018:ffffc9000363f998 EFLAGS: 00000286 RAX: d0e334b002f7e900 RBX: ffff88801e548034 RCX: ffffffff913d0003 RDX: dffffc0000000000 RSI: ffffffff8a8b0ce0 RDI: ffffffff8ad87900 RBP: ffffc9000363fa10 R08: ffffffff818694d0 R09: ffffed10173472e1 R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000 R13: 1ffff1101734748b R14: ffff8880b9a3a458 R15: ffff8880b9a39700 finish_task_switch+0x134/0x630 kernel/sched/core.c:4898 context_switch kernel/sched/core.c:5029 [inline] __schedule+0x12cc/0x4590 kernel/sched/core.c:6372 schedule+0x11b/0x1f0 kernel/sched/core.c:6455 freezable_schedule include/linux/freezer.h:172 [inline] do_nanosleep+0x1bc/0x7b0 kernel/time/hrtimer.c:2044 hrtimer_nanosleep+0x24d/0x490 kernel/time/hrtimer.c:2097 __do_sys_clock_nanosleep kernel/time/posix-timers.c:1308 [inline] __se_sys_clock_nanosleep+0x323/0x3b0 kernel/time/posix-timers.c:1285 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7fcbf789def5 Code: 24 0c 89 3c 24 48 89 4c 24 18 e8 f6 b9 ff ff 4c 8b 54 24 18 48 8b 54 24 10 41 89 c0 8b 74 24 0c 8b 3c 24 b8 e6 00 00 00 0f 05 <44> 89 c7 48 89 04 24 e8 4f ba ff ff 48 8b 04 24 48 83 c4 28 f7 d8 RSP: 002b:00007fff1ad65f50 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6 RAX: ffffffffffffffda RBX: 00007fcbf7991f80 RCX: 00007fcbf789def5 RDX: 00007fff1ad65f90 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007fcbf7993980 R08: 0000000000000000 R09: 0000000000000010 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000105858 R13: ffffffffffffffff R14: 00007fcbf73f6000 R15: 0000000000105517 rcu: rcu_preempt kthread starved for 10460 jiffies! g81769 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:26744 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5026 [inline] __schedule+0x12c4/0x4590 kernel/sched/core.c:6372 schedule+0x11b/0x1f0 kernel/sched/core.c:6455 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1884 rcu_gp_fqs_loop+0x2af/0xf70 kernel/rcu/tree.c:1959 rcu_gp_kthread+0xa4/0x360 kernel/rcu/tree.c:2132 kthread+0x3f6/0x4f0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298 rcu: Stack dump where RCU GP kthread last ran: NMI backtrace for cpu 1 CPU: 1 PID: 3594 Comm: kworker/1:5 Not tainted 5.15.131-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/04/2023 Workqueue: events fqdir_free_fn Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106 nmi_cpu_backtrace+0x46a/0x4a0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x181/0x2a0 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline] rcu_check_gp_kthread_starvation+0x1d2/0x240 kernel/rcu/tree_stall.h:481 print_other_cpu_stall+0x137a/0x14d0 kernel/rcu/tree_stall.h:586 check_cpu_stall kernel/rcu/tree_stall.h:729 [inline] rcu_pending kernel/rcu/tree.c:3911 [inline] rcu_sched_clock_irq+0x94f/0x1770 kernel/rcu/tree.c:2606 update_process_times+0x196/0x200 kernel/time/timer.c:1788 tick_sched_handle kernel/time/tick-sched.c:254 [inline] tick_sched_timer+0x386/0x550 kernel/time/tick-sched.c:1473 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x55b/0xcf0 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1085 [inline] __sysvec_apic_timer_interrupt+0x139/0x470 arch/x86/kernel/apic/apic.c:1102 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1096 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:csd_lock_wait kernel/smp.c:440 [inline] RIP: 0010:smp_call_function_single+0x292/0x530 kernel/smp.c:758 Code: 0f 85 24 02 00 00 44 8b 6c 24 48 44 89 ee 83 e6 01 31 ff e8 b0 d6 0b 00 41 83 e5 01 75 0a e8 45 d3 0b 00 e9 eb 00 00 00 f3 90 <42> 0f b6 04 23 84 c0 75 15 f7 44 24 48 01 00 00 00 0f 84 cd 00 00 RSP: 0018:ffffc9000451fa60 EFLAGS: 00000293 RAX: ffffffff81744a3e RBX: 1ffff920008a3f55 RCX: ffff8880250a5940 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000451fb50 R08: ffffffff81744a10 R09: ffffed10173474f9 R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000 R13: 0000000000000001 R14: ffffc9000451faa8 R15: 0000000000000000 rcu_barrier+0x262/0x4e0 kernel/rcu/tree.c:4057 fqdir_free_fn+0x2e/0x130 net/ipv4/inet_fragment.c:163 process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310 worker_thread+0xaca/0x1280 kernel/workqueue.c:2457 kthread+0x3f6/0x4f0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298