rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P3503/1:b..l (detected by 1, t=10502 jiffies, g=11229, q=380) task:syz-executor state:R running task stack:20696 pid: 3503 ppid: 3499 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5030 [inline] __schedule+0x12c4/0x45b0 kernel/sched/core.c:6376 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6780 irqentry_exit+0x53/0x80 kernel/entry/common.c:432 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:path_init+0xdc6/0x1190 Code: 31 ff e8 ad f6 a6 ff f6 c3 01 48 8b 6c 24 28 75 07 e8 3e f3 a6 ff eb 0d e8 37 f3 a6 ff 4c 89 ef e8 1f 68 fc ff 4c 8b 6c 24 10 <8b> 5c 24 0c 89 de 81 e6 00 00 18 00 31 ff e8 77 f6 a6 ff 81 e3 00 RSP: 0018:ffffc90002de7b20 EFLAGS: 00000293 RAX: ffffffff81d96480 RBX: ffff888023c7f898 RCX: ffff888074340000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc90002de7c60 R08: ffffffff81d9632d R09: fffff520005bcf8a R10: 0000000000000000 R11: dffffc0000000001 R12: ffffc90002de7c7c R13: ffffc90002de7c40 R14: dffffc0000000000 R15: ffff888079bf6620 path_parentat fs/namei.c:2501 [inline] __filename_parentat+0x241/0x6c0 fs/namei.c:2526 filename_parentat fs/namei.c:2544 [inline] do_unlinkat+0x184/0x950 fs/namei.c:4319 __do_sys_unlink fs/namei.c:4396 [inline] __se_sys_unlink fs/namei.c:4394 [inline] __x64_sys_unlink+0x45/0x50 fs/namei.c:4394 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f2a02651137 RSP: 002b:00007ffc677e2fe8 EFLAGS: 00000206 ORIG_RAX: 0000000000000057 RAX: ffffffffffffffda RBX: 0000000000000d56 RCX: 00007f2a02651137 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007ffc677e30a0 RBP: 00007ffc677e30a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 00007ffc677e4190 R13: 00007f2a026bf64a R14: 00005555557b84a8 R15: 0000000000000006 rcu: rcu_preempt kthread starved for 10525 jiffies! g11229 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:27064 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5030 [inline] __schedule+0x12c4/0x45b0 kernel/sched/core.c:6376 schedule+0x11b/0x1f0 kernel/sched/core.c:6459 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1914 rcu_gp_fqs_loop+0x2bf/0x1080 kernel/rcu/tree.c:1972 rcu_gp_kthread+0xa4/0x360 kernel/rcu/tree.c:2145 kthread+0x3f6/0x4f0 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:300 rcu: Stack dump where RCU GP kthread last ran: NMI backtrace for cpu 1 CPU: 1 PID: 4401 Comm: syz.0.208 Not tainted 5.15.161-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2d0 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:487 print_other_cpu_stall+0x137a/0x14d0 kernel/rcu/tree_stall.h:592 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline] rcu_pending kernel/rcu/tree.c:3932 [inline] rcu_sched_clock_irq+0xa38/0x1150 kernel/rcu/tree.c:2619 update_process_times+0x196/0x200 kernel/time/timer.c:1818 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:1686 [inline] __hrtimer_run_queues+0x55b/0xcf0 kernel/time/hrtimer.c:1750 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1812 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:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline] RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202 Code: 21 80 f6 ff 90 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 be 11 3b f7 48 89 df e8 96 65 3c f7 e8 b1 1d 5f f7 fb bf 01 00 00 00 d6 ab 2f f7 65 8b 05 57 b2 da 75 85 c0 74 02 5b c3 e8 24 cf d8 RSP: 0018:ffffc90002dd7bc0 EFLAGS: 00000282 RAX: 58ded9a64f01a100 RBX: ffff888023294a00 RCX: ffffffff913f0f03 RDX: dffffc0000000000 RSI: ffffffff8a8b2a00 RDI: 0000000000000001 RBP: 0000000000000000 R08: ffffffff8186db40 R09: ffffed1004652941 R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000021 R13: dffffc0000000000 R14: ffff888023294e98 R15: ffff888023294a00 spin_unlock_irq include/linux/spinlock.h:413 [inline] get_signal+0x13ee/0x14e0 kernel/signal.c:2892 arch_do_signal_or_restart+0xc3/0x1890 arch/x86/kernel/signal.c:867 handle_signal_work kernel/entry/common.c:154 [inline] exit_to_user_mode_loop+0x97/0x130 kernel/entry/common.c:178 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x5d/0x240 kernel/entry/common.c:307 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7ffe76ded9f4 Code: b8 01 00 00 00 89 f9 d3 e0 a9 83 08 00 00 0f 84 50 01 00 00 4c 8d 15 9b b6 ff ff 41 89 f9 49 c1 e1 04 4f 8d 44 0a 20 45 8b 1a <41> f6 c3 01 75 3f 41 8b 42 04 83 f8 01 75 48 0f 01 f9 66 90 48 c1 RSP: 002b:00007ffe76ddcb78 EFLAGS: 00000202 RAX: 0000000000000002 RBX: 0000000000018ed8 RCX: 0000000000000001 RDX: 0000000000000000 RSI: 00007ffe76ddccf0 RDI: 0000000000000001 RBP: 00007ffe76ddcbd0 R08: 00007ffe76de90b0 R09: 0000000000000010 R10: 00007ffe76de9080 R11: 000000000000731c R12: 00007f5465fa9fac R13: 0000000000000032 R14: 00007ffe76ddccf0 R15: 00007ffe76ddccd0