rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=0c1/1/0x4000000000000000 softirq=319125/319126 fqs=2 (detected by 0, t=10502 jiffies, g=622261, q=91) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 9983 Comm: syz-executor.3 Not tainted 5.15.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:check_kcov_mode kernel/kcov.c:163 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0xd/0x60 kernel/kcov.c:197 Code: ff ff ba 08 00 00 00 4d 8b 03 48 0f bd ca 49 8b 45 00 48 63 c9 e9 64 ff ff ff 0f 1f 00 65 8b 05 69 fd 8a 7e 89 c1 48 8b 34 24 <81> e1 00 01 00 00 65 48 8b 14 25 40 70 02 00 a9 00 01 ff 00 74 0e RSP: 0018:ffffc90000dc0dc8 EFLAGS: 00000082 RAX: 0000000080010002 RBX: 0000000000000000 RCX: 0000000080010002 RDX: 1ffff1100ee9db68 RSI: ffffffff83f500ce RDI: ffff8880774edb40 RBP: ffff8880774edb40 R08: ffff8880774edb40 R09: 0000000000000000 R10: ffffffff83f4ff54 R11: 0000000000000000 R12: ffff8880b9d2a400 R13: 0000000000000000 R14: ffff8880b9d2a401 R15: 0000000000000001 FS: 00007f80463d8700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000561c25baeeb8 CR3: 0000000086321000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: timerqueue_add+0x1be/0x330 lib/timerqueue.c:40 enqueue_hrtimer+0x176/0x3e0 kernel/time/hrtimer.c:1091 __run_hrtimer kernel/time/hrtimer.c:1702 [inline] __hrtimer_run_queues+0xb02/0xe50 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:page_remove_rmap+0x93/0x1480 mm/rmap.c:1350 Code: c6 ff 48 8d 7b 18 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 9e 11 00 00 48 8b 5b 18 31 ff 83 e3 01 <89> de e8 76 24 c6 ff 84 db 0f 84 a9 05 00 00 e8 29 1e c6 ff 31 ff RSP: 0018:ffffc90004f5f7e8 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc900167f9000 RDX: 1ffffd4000085ddb RSI: ffffffff81b1542b RDI: 0000000000000000 RBP: ffffea000042eec0 R08: 0000000000000000 R09: ffff888010e6d083 R10: ffffffff81b15415 R11: 0000000000000000 R12: ffffea000042eec8 R13: 0000000000000000 R14: 0000000000000000 R15: 00000000203e5000 zap_pte_range mm/memory.c:1362 [inline] zap_pmd_range mm/memory.c:1481 [inline] zap_pud_range mm/memory.c:1510 [inline] zap_p4d_range mm/memory.c:1531 [inline] unmap_page_range+0xed5/0x2a10 mm/memory.c:1552 unmap_single_vma+0x198/0x310 mm/memory.c:1597 unmap_vmas+0x16b/0x2f0 mm/memory.c:1629 unmap_region+0x204/0x350 mm/mmap.c:2650 __do_munmap+0x627/0x11c0 mm/mmap.c:2884 do_munmap mm/mmap.c:2895 [inline] munmap_vma_range mm/mmap.c:603 [inline] mmap_region+0x2fd/0x1650 mm/mmap.c:1742 do_mmap+0x869/0xfb0 mm/mmap.c:1575 vm_mmap_pgoff+0x1b7/0x290 mm/util.c:519 ksys_mmap_pgoff+0xe1/0x620 mm/mmap.c:1624 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f8048e62ae9 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f80463d8188 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007f8048f75f60 RCX: 00007f8048e62ae9 RDX: 0000000000000003 RSI: 0000000000b36000 RDI: 0000000020000000 RBP: 00007f8048ebcf25 R08: ffffffffffffffff R09: 0000000000000000 R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffe9ed0662f R14: 00007f80463d8300 R15: 0000000000022000 rcu: rcu_preempt kthread starved for 10498 jiffies! g622261 f0x0 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: 56 Comm: kworker/u4:3 Not tainted 5.15.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events_unbound toggle_allocation_gate 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:check_kcov_mode+0x31/0x40 kernel/kcov.c:175 Code: 89 c2 81 e2 00 01 00 00 a9 00 01 ff 00 74 10 31 c0 85 d2 74 15 8b 96 a4 15 00 00 85 d2 74 0b 8b 86 80 15 00 00 39 f8 0f 94 c0 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 31 c0 65 8b 15 77 05 RSP: 0018:ffffc90001a2f9e8 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffff8880b9d3fca0 RCX: 0000000000000001 RDX: 0000000000000000 RSI: ffff8880175c0000 RDI: 0000000000000003 RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000001 R10: ffffffff816c0e46 R11: 0000000000000000 R12: ffffed10173a7f95 R13: 0000000000000001 R14: ffff8880b9d3fca8 R15: 0000000000000001 write_comp_data kernel/kcov.c:218 [inline] __sanitizer_cov_trace_const_cmp4+0x1c/0x70 kernel/kcov.c:284 csd_lock_wait kernel/smp.c:440 [inline] smp_call_function_many_cond+0x476/0xc20 kernel/smp.c:969 on_each_cpu_cond_mask+0x56/0xa0 kernel/smp.c:1135 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:1112 [inline] text_poke_bp_batch+0x1b3/0x560 arch/x86/kernel/alternative.c:1297 text_poke_flush arch/x86/kernel/alternative.c:1451 [inline] text_poke_flush arch/x86/kernel/alternative.c:1448 [inline] text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1458 arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146 jump_label_update+0x1d5/0x430 kernel/jump_label.c:830 static_key_enable_cpuslocked+0x1b1/0x260 kernel/jump_label.c:177 static_key_enable+0x16/0x20 kernel/jump_label.c:190 toggle_allocation_gate mm/kfence/core.c:626 [inline] toggle_allocation_gate+0x100/0x390 mm/kfence/core.c:618 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), 2 bytes skipped: 0: ba 08 00 00 00 mov $0x8,%edx 5: 4d 8b 03 mov (%r11),%r8 8: 48 0f bd ca bsr %rdx,%rcx c: 49 8b 45 00 mov 0x0(%r13),%rax 10: 48 63 c9 movslq %ecx,%rcx 13: e9 64 ff ff ff jmpq 0xffffff7c 18: 0f 1f 00 nopl (%rax) 1b: 65 8b 05 69 fd 8a 7e mov %gs:0x7e8afd69(%rip),%eax # 0x7e8afd8b 22: 89 c1 mov %eax,%ecx 24: 48 8b 34 24 mov (%rsp),%rsi * 28: 81 e1 00 01 00 00 and $0x100,%ecx <-- trapping instruction 2e: 65 48 8b 14 25 40 70 mov %gs:0x27040,%rdx 35: 02 00 37: a9 00 01 ff 00 test $0xff0100,%eax 3c: 74 0e je 0x4c