rcu: INFO: rcu_sched detected stalls on CPUs/tasks: rcu: 1-...!: (10502 ticks this GP) idle=9e2/1/0x4000000000000002 softirq=36117/36117 fqs=0 rcu: (detected by 0, t=10502 jiffies, g=1621, q=17) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 25495 Comm: syz-executor.5 Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__sanitizer_cov_trace_pc+0x22/0x50 kernel/kcov.c:101 Code: 90 90 90 90 90 90 90 90 48 8b 34 24 65 48 8b 04 25 c0 df 01 00 65 8b 15 cc 59 9f 7e 81 e2 00 01 1f 00 75 2b 8b 90 60 13 00 00 <83> fa 02 75 20 48 8b 88 68 13 00 00 8b 80 64 13 00 00 48 8b 11 48 RSP: 0018:ffff8880ba107f70 EFLAGS: 00000046 RAX: ffff888023368340 RBX: 0000000000022ac0 RCX: 1ffffffff139f5e1 RDX: 0000000000000000 RSI: ffffffff83772075 RDI: ffffffff89cfaf08 RBP: ffff8880ba122ac0 R08: ffffffff8c665058 R09: 0000000000000000 R10: 0000000000000005 R11: ffffffff8c66505b R12: ffff8880ba122ac8 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f77eeaee700(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f77eeaee6bc CR3: 000000001e213000 CR4: 00000000003406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: debug_smp_processor_id+0x5/0x20 lib/smp_processor_id.c:56 rcu_dynticks_curr_cpu_in_eqs kernel/rcu/tree.c:348 [inline] rcu_nmi_exit+0x75/0x180 kernel/rcu/tree.c:794 irq_exit+0xb7/0x260 kernel/softirq.c:415 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0x136/0x550 arch/x86/kernel/apic/apic.c:1098 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:894 RIP: 0010:check_kcov_mode kernel/kcov.c:67 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x14/0x50 kernel/kcov.c:101 Code: 35 00 e9 23 fe ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 48 8b 34 24 65 48 8b 04 25 c0 df 01 00 65 8b 15 cc 59 9f 7e <81> e2 00 01 1f 00 75 2b 8b 90 60 13 00 00 83 fa 02 75 20 48 8b 88 RSP: 0018:ffff8880233776d0 EFLAGS: 00000202 ORIG_RAX: ffffffffffffff13 RAX: ffff888023368340 RBX: 0000000000000002 RCX: ffffffff83771e23 RDX: 0000000080000002 RSI: ffffffff83771e2c RDI: 0000000000000005 RBP: ffffffff88b3e120 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000005 R11: 0000000000000000 R12: 0000000000000001 R13: ffffffff88b3e0e0 R14: dead000000000100 R15: 00007f77ef58b000 check_preemption_disabled+0x3c/0x280 lib/smp_processor_id.c:25 rcu_dynticks_curr_cpu_in_eqs kernel/rcu/tree.c:348 [inline] rcu_is_watching+0x12/0xc0 kernel/rcu/tree.c:1025 rcu_read_unlock include/linux/rcupdate.h:677 [inline] __unlock_page_memcg+0x72/0x100 mm/memcontrol.c:1955 page_remove_rmap+0xe5/0x120 mm/rmap.c:1297 zap_pte_range mm/memory.c:1350 [inline] zap_pmd_range mm/memory.c:1463 [inline] zap_pud_range mm/memory.c:1492 [inline] zap_p4d_range mm/memory.c:1513 [inline] unmap_page_range+0x147d/0x2c50 mm/memory.c:1534 unmap_single_vma+0x198/0x300 mm/memory.c:1579 unmap_vmas+0xa9/0x180 mm/memory.c:1609 exit_mmap+0x2b9/0x530 mm/mmap.c:3093 __mmput kernel/fork.c:1016 [inline] mmput+0x14e/0x4a0 kernel/fork.c:1037 exit_mm kernel/exit.c:549 [inline] do_exit+0xaec/0x2be0 kernel/exit.c:857 do_group_exit+0x125/0x310 kernel/exit.c:967 get_signal+0x3f2/0x1f70 kernel/signal.c:2589 do_signal+0x8f/0x1670 arch/x86/kernel/signal.c:799 exit_to_usermode_loop+0x204/0x2a0 arch/x86/entry/common.c:163 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:271 [inline] do_syscall_64+0x538/0x620 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f77f01bae99 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:00007f77eeaee168 EFLAGS: 00000246 ORIG_RAX: 0000000000000039 RAX: fffffffffffffff4 RBX: 00007f77f02ce100 RCX: 00007f77f01bae99 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f77f0214ff1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffe4d72506f R14: 00007f77eeaee300 R15: 0000000000022000 rcu: rcu_sched kthread starved for 10502 jiffies! g1621 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=1 rcu: RCU grace-period kthread stack dump: rcu_sched I29728 11 2 0x80000000 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x887/0x2040 kernel/sched/core.c:3517 schedule+0x8d/0x1b0 kernel/sched/core.c:3561 schedule_timeout+0x4cf/0xfe0 kernel/time/timer.c:1818 rcu_gp_kthread+0xdad/0x21c0 kernel/rcu/tree.c:2202 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 ---------------- Code disassembly (best guess): 0: 90 nop 1: 90 nop 2: 90 nop 3: 90 nop 4: 90 nop 5: 90 nop 6: 90 nop 7: 90 nop 8: 48 8b 34 24 mov (%rsp),%rsi c: 65 48 8b 04 25 c0 df mov %gs:0x1dfc0,%rax 13: 01 00 15: 65 8b 15 cc 59 9f 7e mov %gs:0x7e9f59cc(%rip),%edx # 0x7e9f59e8 1c: 81 e2 00 01 1f 00 and $0x1f0100,%edx 22: 75 2b jne 0x4f 24: 8b 90 60 13 00 00 mov 0x1360(%rax),%edx * 2a: 83 fa 02 cmp $0x2,%edx <-- trapping instruction 2d: 75 20 jne 0x4f 2f: 48 8b 88 68 13 00 00 mov 0x1368(%rax),%rcx 36: 8b 80 64 13 00 00 mov 0x1364(%rax),%eax 3c: 48 8b 11 mov (%rcx),%rdx 3f: 48 rex.W