rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6555/1:b..l (detected by 0, t=10502 jiffies, g=404505, q=5882) task:syz-executor.0 state:R running task stack:22760 pid: 6555 ppid: 6554 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0x940/0x26f0 kernel/sched/core.c:6287 preempt_schedule_common+0x45/0xc0 kernel/sched/core.c:6459 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:35 __raw_read_unlock include/linux/rwlock_api_smp.h:227 [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:542 [inline] forget_original_parent kernel/exit.c:631 [inline] exit_notify kernel/exit.c:668 [inline] do_exit+0x234c/0x2a30 kernel/exit.c:845 do_group_exit+0x125/0x310 kernel/exit.c:922 __do_sys_exit_group kernel/exit.c:933 [inline] __se_sys_exit_group kernel/exit.c:931 [inline] __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:931 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: 0033:0x7ff693c6c739 RSP: 002b:00007ffc56ee28d8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00000000ffffffff RCX: 00007ff693c6c739 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000043 RBP: 0000000000000000 R08: 000000000000002e R09: 00000000ffffffff R10: 0000000000000000 R11: 0000000000000246 R12: 00007ff693cc6d2a R13: 000000000000000b R14: 0000000000000001 R15: 00007ffc56ee2ad0 rcu: rcu_preempt kthread timer wakeup didn't happen for 9148 jiffies! g404505 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=136503 rcu: rcu_preempt kthread starved for 9149 jiffies! g404505 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=1 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:28696 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: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 18700 Comm: syz-executor.5 Not tainted 5.15.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:163 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x60 kernel/kcov.c:197 Code: 01 f0 4d 89 03 e9 63 fd ff ff b9 ff ff 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 19 e2 8b 7e 89 c1 48 8b 34 24 81 e1 00 01 00 00 65 48 8b RSP: 0018:ffffc90000dc0e98 EFLAGS: 00000046 RAX: ffffed10173a4485 RBX: 000002433a1730d5 RCX: 0000000000000000 RDX: ffff88814e3cd580 RSI: ffffffff8165889e RDI: 0000000000000003 RBP: 0000000000000006 R08: 000002433a1730d5 R09: 0000000000000000 R10: ffffffff8165882e R11: 0000000000000000 R12: ffff888145a36a98 R13: ffff8880b9d223c0 R14: 000002433a1730d5 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f6a0f12075c CR3: 000000003ded4000 CR4: 0000000000350ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: __next_base kernel/time/hrtimer.c:490 [inline] __hrtimer_next_event_base+0x56/0x260 kernel/time/hrtimer.c:510 __hrtimer_get_next_event kernel/time/hrtimer.c:587 [inline] hrtimer_update_next_event+0xcd/0x2a0 kernel/time/hrtimer.c:612 hrtimer_interrupt+0x324/0x790 kernel/time/hrtimer.c:1814 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:finish_task_switch.isra.0+0x23c/0xa50 kernel/sched/core.c:4814 Code: 8b 3a 4c 89 e7 48 c7 02 00 00 00 00 ff d1 4d 85 ff 75 bf 4c 89 e7 e8 f3 66 e7 07 e8 fe 2c 2c 00 fb 65 48 8b 1c 25 40 f0 01 00 <48> 8d bb 18 15 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 RSP: 0018:ffffc90018d9f5f8 EFLAGS: 00000202 RAX: 0000000000001bfd RBX: ffff88814e3cd580 RCX: 1ffffffff1adc3a9 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90018d9f638 R08: 0000000000000001 R09: 0000000000000001 R10: ffffffff817c37a8 R11: 0000000000000000 R12: ffff8880b9d31a40 R13: ffff888153a35580 R14: 0000000000000000 R15: ffff8880b9d31a58 context_switch kernel/sched/core.c:4943 [inline] __schedule+0x948/0x26f0 kernel/sched/core.c:6287 preempt_schedule_common+0x45/0xc0 kernel/sched/core.c:6459 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:35 __raw_spin_unlock include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock+0x36/0x40 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:403 [inline] zap_pte_range mm/memory.c:1422 [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+0x1044/0x2a10 mm/memory.c:1552 unmap_single_vma+0x198/0x310 mm/memory.c:1597 unmap_vmas+0x16d/0x2f0 mm/memory.c:1629 exit_mmap+0x1d0/0x630 mm/mmap.c:3171 __mmput+0x122/0x4b0 kernel/fork.c:1115 mmput+0x58/0x60 kernel/fork.c:1136 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:2868 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: 0033:0x7fadb0dcb739 Code: Unable to access opcode bytes at RIP 0x7fadb0dcb70f. RSP: 002b:00007fadae342218 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007fadb0ecff88 RCX: 00007fadb0dcb739 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fadb0ecff88 RBP: 00007fadb0ecff80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fadb0ecff8c R13: 00007ffcd176582f R14: 00007fadae342300 R15: 0000000000022000 ---------------- Code disassembly (best guess): 0: 01 f0 add %esi,%eax 2: 4d 89 03 mov %r8,(%r11) 5: e9 63 fd ff ff jmpq 0xfffffd6d a: b9 ff ff ff ff mov $0xffffffff,%ecx f: ba 08 00 00 00 mov $0x8,%edx 14: 4d 8b 03 mov (%r11),%r8 17: 48 0f bd ca bsr %rdx,%rcx 1b: 49 8b 45 00 mov 0x0(%r13),%rax 1f: 48 63 c9 movslq %ecx,%rcx 22: e9 64 ff ff ff jmpq 0xffffff8b 27: 0f 1f 00 nopl (%rax) * 2a: 65 8b 05 19 e2 8b 7e mov %gs:0x7e8be219(%rip),%eax # 0x7e8be24a <-- trapping instruction 31: 89 c1 mov %eax,%ecx 33: 48 8b 34 24 mov (%rsp),%rsi 37: 81 e1 00 01 00 00 and $0x100,%ecx 3d: 65 gs 3e: 48 rex.W 3f: 8b .byte 0x8b