rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P17589/1:b..l (detected by 0, t=10502 jiffies, g=454761, q=4291) task:syz-executor.3 state:R running task stack:24256 pid:17589 ppid: 1 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:4972 [inline] __schedule+0xa9a/0x4940 kernel/sched/core.c:6253 preempt_schedule_common+0x45/0xc0 kernel/sched/core.c:6419 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:35 __raw_read_unlock include/linux/rwlock_api_smp.h:225 [inline] _raw_read_unlock+0x36/0x40 kernel/locking/spinlock.c:260 zap_pid_ns_processes+0x271/0x660 kernel/pid_namespace.c:207 find_child_reaper kernel/exit.c:548 [inline] forget_original_parent kernel/exit.c:637 [inline] exit_notify kernel/exit.c:674 [inline] do_exit+0x243d/0x2b40 kernel/exit.c:852 do_group_exit+0x125/0x310 kernel/exit.c:929 get_signal+0x47d/0x2220 kernel/signal.c:2830 arch_do_signal_or_restart+0x2a9/0x1c40 arch/x86/kernel/signal.c:868 handle_signal_work kernel/entry/common.c:148 [inline] exit_to_user_mode_loop kernel/entry/common.c:172 [inline] exit_to_user_mode_prepare+0x17d/0x290 kernel/entry/common.c:207 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline] syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:300 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7fec2966c811 RSP: 002b:00007ffc2a643390 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6 RAX: 0000000000000000 RBX: 000000000000117d RCX: 00007fec2966c811 RDX: 00007ffc2a6433d0 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007ffc2a64345c R08: 0000000000000000 R09: 00007ffc2a709080 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000038 R13: 00000000002bbd9a R14: 0000000000000000 R15: 00007ffc2a6434c0 rcu: rcu_preempt kthread timer wakeup didn't happen for 3564 jiffies! g454761 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=161539 rcu: rcu_preempt kthread starved for 3565 jiffies! g454761 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:28256 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4972 [inline] __schedule+0xa9a/0x4940 kernel/sched/core.c:6253 schedule+0xd2/0x260 kernel/sched/core.c:6326 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: 32749 Comm: syz-executor.4 Not tainted 5.16.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 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:__sanitizer_cov_trace_pc+0x5c/0x60 kernel/kcov.c:210 Code: 82 80 15 00 00 83 f8 02 75 20 48 8b 8a 88 15 00 00 8b 92 84 15 00 00 48 8b 01 48 83 c0 01 48 39 c2 76 07 48 89 34 c1 48 89 01 0f 1f 00 41 55 41 54 49 89 fc 55 48 bd eb 83 b5 80 46 86 c8 61 RSP: 0018:ffffc9001bd177a0 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffffea0000f5f640 RCX: 0000000000000000 RDX: ffff888031a8e1c0 RSI: ffffffff81abc9c3 RDI: 0000000000000003 RBP: ffffea0000f5f640 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff81abc9ad R11: 0000000000000000 R12: ffffea0000f5f648 R13: ffff88817b1a24d0 R14: dffffc0000000000 R15: 00007f3b3189b000 folio_test_anon include/linux/page-flags.h:581 [inline] PageAnon include/linux/page-flags.h:586 [inline] mm_counter include/linux/mm.h:2075 [inline] zap_pte_range mm/memory.c:1356 [inline] zap_pmd_range mm/memory.c:1467 [inline] zap_pud_range mm/memory.c:1496 [inline] zap_p4d_range mm/memory.c:1517 [inline] unmap_page_range+0xdb3/0x29f0 mm/memory.c:1538 unmap_single_vma+0x198/0x310 mm/memory.c:1583 unmap_vmas+0x16b/0x2f0 mm/memory.c:1615 exit_mmap+0x1d0/0x630 mm/mmap.c:3170 __mmput+0x122/0x4b0 kernel/fork.c:1113 mmput+0x56/0x60 kernel/fork.c:1134 exit_mm kernel/exit.c:507 [inline] do_exit+0xb27/0x2b40 kernel/exit.c:819 do_group_exit+0x125/0x310 kernel/exit.c:929 get_signal+0x47d/0x2220 kernel/signal.c:2830 arch_do_signal_or_restart+0x2a9/0x1c40 arch/x86/kernel/signal.c:868 handle_signal_work kernel/entry/common.c:148 [inline] exit_to_user_mode_loop kernel/entry/common.c:172 [inline] exit_to_user_mode_prepare+0x17d/0x290 kernel/entry/common.c:207 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline] syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:300 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f3b32920ae9 Code: Unable to access opcode bytes at RIP 0x7f3b32920abf. RSP: 002b:00007f3b2fe96218 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007f3b32a33f68 RCX: 00007f3b32920ae9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f3b32a33f68 RBP: 00007f3b32a33f60 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f3b32a33f6c R13: 00007ffc1e18faff R14: 00007f3b2fe96300 R15: 0000000000022000 ---------------- Code disassembly (best guess), 1 bytes skipped: 0: 80 15 00 00 83 f8 02 adcb $0x2,-0x77d0000(%rip) # 0xf8830007 7: 75 20 jne 0x29 9: 48 8b 8a 88 15 00 00 mov 0x1588(%rdx),%rcx 10: 8b 92 84 15 00 00 mov 0x1584(%rdx),%edx 16: 48 8b 01 mov (%rcx),%rax 19: 48 83 c0 01 add $0x1,%rax 1d: 48 39 c2 cmp %rax,%rdx 20: 76 07 jbe 0x29 22: 48 89 34 c1 mov %rsi,(%rcx,%rax,8) 26: 48 89 01 mov %rax,(%rcx) * 29: c3 retq <-- trapping instruction 2a: 0f 1f 00 nopl (%rax) 2d: 41 55 push %r13 2f: 41 54 push %r12 31: 49 89 fc mov %rdi,%r12 34: 55 push %rbp 35: 48 bd eb 83 b5 80 46 movabs $0x61c8864680b583eb,%rbp 3c: 86 c8 61