rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P17394/1:b..l (detected by 1, t=10502 jiffies, g=148181, q=22952) task:syz-executor.0 state:R running task stack:23912 pid:17394 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:2852 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: 0033:0x7ff8d4001811 RSP: 002b:00007ff8d4623d10 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6 RAX: 0000000000000000 RBX: 0000000000001491 RCX: 00007ff8d4001811 RDX: 00007ff8d4623d50 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007ff8d4623ddc R08: 0000000000000000 R09: 00007fffca77f080 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000050 R13: 000000000010fed6 R14: 0000000000000000 R15: 00007ff8d4623e40 rcu: rcu_preempt kthread timer wakeup didn't happen for 5338 jiffies! g148181 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=55845 rcu: rcu_preempt kthread starved for 5339 jiffies! g148181 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:28688 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: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 8110 Comm: syz-executor.0 Not tainted 5.16.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:rcu_rnp_online_cpus kernel/rcu/tree.c:221 [inline] RIP: 0010:rcu_lockdep_current_cpu_online kernel/rcu/tree.c:1171 [inline] RIP: 0010:rcu_lockdep_current_cpu_online+0xc5/0x150 kernel/rcu/tree.c:1160 Code: 48 89 fa 48 c1 ea 03 80 3c 02 00 75 7b 48 8d 7d 70 48 8b 5b 20 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 <75> 66 48 8b 45 70 48 85 c3 74 11 b8 01 00 00 00 65 ff 0d 34 4f 9f RSP: 0000:ffffc90000007e28 EFLAGS: 00000046 RAX: dffffc0000000000 RBX: 0000000000000001 RCX: ffffffff815caee1 RDX: 1ffffffff177194e RSI: 0000000000010004 RDI: ffffffff8bb8ca70 RBP: ffffffff8bb8ca00 R08: 0000000000000000 R09: ffffffff8d912ad7 R10: fffffbfff1b2255a R11: 0000000000000000 R12: 0000000000000001 R13: 7fffffffffffffff R14: 0000000000000000 R15: ffff8880b9c2a400 FS: 0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f05eb52f048 CR3: 0000000071d87000 CR4: 00000000003506f0 DR0: 0000000020000080 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: rcu_read_lock_held_common kernel/rcu/update.c:112 [inline] rcu_read_lock_held_common kernel/rcu/update.c:102 [inline] rcu_read_lock_sched_held+0x25/0x70 kernel/rcu/update.c:123 trace_lock_release include/trace/events/lock.h:58 [inline] lock_release+0x522/0x720 kernel/locking/lockdep.c:5648 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:149 [inline] _raw_spin_unlock_irqrestore+0x16/0x70 kernel/locking/spinlock.c:194 hrtimer_interrupt+0x364/0x790 kernel/time/hrtimer.c:1821 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+0x323/0xb80 kernel/sched/core.c:4852 Code: 63 78 f3 07 85 c0 75 02 0f 0b 48 85 db 0f 85 25 01 00 00 4c 89 f7 e8 fc f7 ff ff e8 c7 46 2d 00 fb 65 48 8b 1c 25 40 70 02 00 <48> 8d bb 80 15 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 RSP: 0000:ffffc9001e35f598 EFLAGS: 00000206 RAX: 0000000000004c9f RBX: ffff88814ed7d700 RCX: 1ffffffff1b21fe9 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9001e35f5e0 R08: 0000000000000001 R09: 0000000000000001 R10: ffffffff817ddf48 R11: 0000000000000000 R12: ffff8880b9c3a7d8 R13: ffff88803725ba00 R14: ffff8880b9c39a80 R15: ffff8880b9c3a4b8 context_switch kernel/sched/core.c:4975 [inline] __schedule+0xaa2/0x4940 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_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x36/0x40 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:389 [inline] zap_pte_range mm/memory.c:1408 [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+0x107c/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:2852 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: 0033:0x7ff8d3fdcae9 Code: Unable to access opcode bytes at RIP 0x7ff8d3fdcabf. RSP: 002b:00007ff8d1552218 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007ff8d40eff68 RCX: 00007ff8d3fdcae9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007ff8d40eff68 RBP: 00007ff8d40eff60 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ff8d40eff6c R13: 00007ff8d4623b2f R14: 00007ff8d1552300 R15: 0000000000022000 ---------------- Code disassembly (best guess): 0: 48 89 fa mov %rdi,%rdx 3: 48 c1 ea 03 shr $0x3,%rdx 7: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) b: 75 7b jne 0x88 d: 48 8d 7d 70 lea 0x70(%rbp),%rdi 11: 48 8b 5b 20 mov 0x20(%rbx),%rbx 15: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 1c: fc ff df 1f: 48 89 fa mov %rdi,%rdx 22: 48 c1 ea 03 shr $0x3,%rdx 26: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) * 2a: 75 66 jne 0x92 <-- trapping instruction 2c: 48 8b 45 70 mov 0x70(%rbp),%rax 30: 48 85 c3 test %rax,%rbx 33: 74 11 je 0x46 35: b8 01 00 00 00 mov $0x1,%eax 3a: 65 gs 3b: ff .byte 0xff 3c: 0d .byte 0xd 3d: 34 4f xor $0x4f,%al 3f: 9f lahf