rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (10500 ticks this GP) idle=faf/1/0x4000000000000000 softirq=120844/120844 fqs=0 (t=10501 jiffies g=211385 q=11677) rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g211385 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=100974 rcu: rcu_preempt kthread starved for 10504 jiffies! g211385 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:28720 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0x940/0x26f0 kernel/sched/core.c:6287 schedule+0xd3/0x270 kernel/sched/core.c:6366 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1881 rcu_gp_fqs_loop+0x186/0x800 kernel/rcu/tree.c:1957 rcu_gp_kthread+0x1de/0x320 kernel/rcu/tree.c:2130 kthread+0x3e5/0x4d0 kernel/kthread.c:319 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: 3039 Comm: syz-executor.2 Not tainted 5.14.0-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:105 nmi_cpu_backtrace.cold+0x44/0xd7 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1b3/0x230 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_cpu_stall kernel/rcu/tree_stall.h:625 [inline] check_cpu_stall kernel/rcu/tree_stall.h:711 [inline] rcu_pending kernel/rcu/tree.c:3880 [inline] rcu_sched_clock_irq.cold+0x98/0x746 kernel/rcu/tree.c:2599 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:_compound_head include/linux/page-flags.h:185 [inline] RIP: 0010:PageSlab include/linux/page-flags.h:345 [inline] RIP: 0010:__page_memcg include/linux/memcontrol.h:402 [inline] RIP: 0010:page_memcg include/linux/memcontrol.h:455 [inline] RIP: 0010:lock_page_memcg+0xb1/0x7d0 mm/memcontrol.c:2016 Code: 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 0f 85 04 05 00 00 49 8b 5f 38 4d 8d 67 08 48 b8 00 00 00 00 00 fc ff df 4d 89 e6 <49> c1 ee 03 49 01 c6 f6 c3 01 0f 85 7c 04 00 00 f6 c3 02 0f 85 42 RSP: 0018:ffffc90017d87708 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff8161d6c4 RDX: 1ffffd400036583f RSI: 0000000000000004 RDI: ffff8880b9c52a88 RBP: ffffc90017d87750 R08: 0000000000000000 R09: ffff8880b9c52a8b R10: ffffed101738a551 R11: 0000000000000000 R12: ffffea0001b2c1c8 R13: 0000000000000000 R14: ffffea0001b2c1c8 R15: ffffea0001b2c1c0 page_remove_rmap+0x25/0x1480 mm/rmap.c:1346 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+0x16d/0x2f0 mm/memory.c:1629 exit_mmap+0x1d0/0x620 mm/mmap.c:3195 __mmput+0x122/0x470 kernel/fork.c:1103 mmput+0x58/0x60 kernel/fork.c:1124 exit_mm kernel/exit.c:501 [inline] do_exit+0xabc/0x2a30 kernel/exit.c:812 do_group_exit+0x125/0x310 kernel/exit.c:922 get_signal+0x47f/0x2160 kernel/signal.c:2823 arch_do_signal_or_restart+0x2a9/0x1c40 arch/x86/kernel/signal.c:865 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:209 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:302 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x4665f9 Code: Unable to access opcode bytes at RIP 0x4665cf. RSP: 002b:00007fb3af96d218 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 000000000056bf88 RCX: 00000000004665f9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000056bf88 RBP: 000000000056bf80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf8c R13: 0000000000a9fb1f R14: 00007fb3af96d300 R15: 0000000000022000 NMI backtrace for cpu 0 CPU: 0 PID: 3039 Comm: syz-executor.2 Not tainted 5.14.0-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:105 nmi_cpu_backtrace.cold+0x44/0xd7 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x25e/0x3f0 kernel/rcu/tree_stall.h:343 print_cpu_stall kernel/rcu/tree_stall.h:627 [inline] check_cpu_stall kernel/rcu/tree_stall.h:711 [inline] rcu_pending kernel/rcu/tree.c:3880 [inline] rcu_sched_clock_irq.cold+0x9d/0x746 kernel/rcu/tree.c:2599 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:_compound_head include/linux/page-flags.h:185 [inline] RIP: 0010:PageSlab include/linux/page-flags.h:345 [inline] RIP: 0010:__page_memcg include/linux/memcontrol.h:402 [inline] RIP: 0010:page_memcg include/linux/memcontrol.h:455 [inline] RIP: 0010:lock_page_memcg+0xb1/0x7d0 mm/memcontrol.c:2016 Code: 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 0f 85 04 05 00 00 49 8b 5f 38 4d 8d 67 08 48 b8 00 00 00 00 00 fc ff df 4d 89 e6 <49> c1 ee 03 49 01 c6 f6 c3 01 0f 85 7c 04 00 00 f6 c3 02 0f 85 42 RSP: 0018:ffffc90017d87708 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff8161d6c4 RDX: 1ffffd400036583f RSI: 0000000000000004 RDI: ffff8880b9c52a88 RBP: ffffc90017d87750 R08: 0000000000000000 R09: ffff8880b9c52a8b R10: ffffed101738a551 R11: 0000000000000000 R12: ffffea0001b2c1c8 R13: 0000000000000000 R14: ffffea0001b2c1c8 R15: ffffea0001b2c1c0 page_remove_rmap+0x25/0x1480 mm/rmap.c:1346 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+0x16d/0x2f0 mm/memory.c:1629 exit_mmap+0x1d0/0x620 mm/mmap.c:3195 __mmput+0x122/0x470 kernel/fork.c:1103 mmput+0x58/0x60 kernel/fork.c:1124 exit_mm kernel/exit.c:501 [inline] do_exit+0xabc/0x2a30 kernel/exit.c:812 do_group_exit+0x125/0x310 kernel/exit.c:922 get_signal+0x47f/0x2160 kernel/signal.c:2823 arch_do_signal_or_restart+0x2a9/0x1c40 arch/x86/kernel/signal.c:865 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:209 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:302 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x4665f9 Code: Unable to access opcode bytes at RIP 0x4665cf. RSP: 002b:00007fb3af96d218 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 000000000056bf88 RCX: 00000000004665f9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000056bf88 RBP: 000000000056bf80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf8c R13: 0000000000a9fb1f R14: 00007fb3af96d300 R15: 0000000000022000 ---------------- Code disassembly (best guess), 7 bytes skipped: 0: 48 c1 ea 03 shr $0x3,%rdx 4: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) 8: 0f 85 04 05 00 00 jne 0x512 e: 49 8b 5f 38 mov 0x38(%r15),%rbx 12: 4d 8d 67 08 lea 0x8(%r15),%r12 16: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 1d: fc ff df 20: 4d 89 e6 mov %r12,%r14 * 23: 49 c1 ee 03 shr $0x3,%r14 <-- trapping instruction 27: 49 01 c6 add %rax,%r14 2a: f6 c3 01 test $0x1,%bl 2d: 0f 85 7c 04 00 00 jne 0x4af 33: f6 c3 02 test $0x2,%bl 36: 0f .byte 0xf 37: 85 .byte 0x85 38: 42 rex.X