rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 0, t=10502 jiffies, g=348109, q=3) rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4295170031-4295159529), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10502 jiffies! g348109 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 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:28696 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4969 [inline] __schedule+0xa9a/0x4940 kernel/sched/core.c:6250 schedule+0xd2/0x260 kernel/sched/core.c:6323 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1881 rcu_gp_fqs_loop+0x186/0x810 kernel/rcu/tree.c:1955 rcu_gp_kthread+0x1de/0x320 kernel/rcu/tree.c:2128 kthread+0x405/0x4f0 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: Stack dump where RCU GP kthread last ran: NMI backtrace for cpu 0 CPU: 0 PID: 11988 Comm: kworker/0:1 Not tainted 5.15.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events prog_array_map_clear_deferred Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1ae/0x220 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_check_gp_kthread_starvation.cold+0x1fb/0x200 kernel/rcu/tree_stall.h:481 print_other_cpu_stall kernel/rcu/tree_stall.h:586 [inline] check_cpu_stall kernel/rcu/tree_stall.h:729 [inline] rcu_pending kernel/rcu/tree.c:3878 [inline] rcu_sched_clock_irq+0x2125/0x2200 kernel/rcu/tree.c:2597 update_process_times+0x16d/0x200 kernel/time/timer.c:1785 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:226 tick_sched_timer+0x1b0/0x2d0 kernel/time/tick-sched.c:1421 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x1c0/0xe50 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:__mutex_unlock_slowpath+0x4/0x5e0 kernel/locking/mutex.c:895 Code: 24 18 e8 5f 8b 84 f8 48 8b 54 24 18 e9 02 ff ff ff 48 8b 7c 24 10 e8 6b 8b 84 f8 e9 ba fe ff ff e8 a1 28 fe ff cc 41 57 41 56 <49> 89 fe 48 83 c7 68 41 55 41 54 55 48 bd 00 00 00 00 00 fc ff df RSP: 0018:ffffc900037cfc20 EFLAGS: 00000246 RAX: ffff88807e646400 RBX: ffffc900189b2000 RCX: 0000000000000000 RDX: 1ffff92003136431 RSI: ffffffff818d6d50 RDI: ffff88807e646460 RBP: 0000000000000000 R08: 0000000000000000 R09: 00000000448f1d01 R10: ffffffff818d6ee9 R11: 0000000000000000 R12: 000000000522766d R13: ffffc900189b2188 R14: ffffffff8993db40 R15: 0000000010000009 fd_array_map_delete_elem+0x1b0/0x2e0 kernel/bpf/arraymap.c:824 bpf_fd_array_map_clear kernel/bpf/arraymap.c:871 [inline] prog_array_map_clear_deferred+0x10b/0x1b0 kernel/bpf/arraymap.c:1050 process_one_work+0x9b2/0x1690 kernel/workqueue.c:2297 worker_thread+0x658/0x11f0 kernel/workqueue.c:2444 kthread+0x405/0x4f0 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 ---------------- Code disassembly (best guess): 0: 24 18 and $0x18,%al 2: e8 5f 8b 84 f8 callq 0xf8848b66 7: 48 8b 54 24 18 mov 0x18(%rsp),%rdx c: e9 02 ff ff ff jmpq 0xffffff13 11: 48 8b 7c 24 10 mov 0x10(%rsp),%rdi 16: e8 6b 8b 84 f8 callq 0xf8848b86 1b: e9 ba fe ff ff jmpq 0xfffffeda 20: e8 a1 28 fe ff callq 0xfffe28c6 25: cc int3 26: 41 57 push %r15 28: 41 56 push %r14 * 2a: 49 89 fe mov %rdi,%r14 <-- trapping instruction 2d: 48 83 c7 68 add $0x68,%rdi 31: 41 55 push %r13 33: 41 54 push %r12 35: 55 push %rbp 36: 48 bd 00 00 00 00 00 movabs $0xdffffc0000000000,%rbp 3d: fc ff df