rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P8473/1:b..l (detected by 1, t=10502 jiffies, g=89809, q=3591) task:syz-executor.0 state:R running task stack:23440 pid: 8468 ppid: 1 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:4681 [inline] __schedule+0x93a/0x26f0 kernel/sched/core.c:5938 preempt_schedule_common+0x45/0xc0 kernel/sched/core.c:6098 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:255 zap_pid_ns_processes+0x271/0x660 kernel/pid_namespace.c:206 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+0x2372/0x2a60 kernel/exit.c:845 do_group_exit+0x125/0x310 kernel/exit.c:922 get_signal+0x47f/0x2160 kernel/signal.c:2808 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: 0033:0x48a7b1 RSP: 002b:00007fff4bc32d20 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6 RAX: 0000000000000000 RBX: 0000000000000d7e RCX: 000000000048a7b1 RDX: 00007fff4bc32d60 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007fff4bc32dfc R08: 0000000000000000 R09: 00007fff4bd97080 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000052 R13: 0000000000099010 R14: 0000000000000013 R15: 00007fff4bc32e60 task:syz-executor.3 state:R running task stack:24152 pid: 8473 ppid: 1 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:4681 [inline] __schedule+0x93a/0x26f0 kernel/sched/core.c:5938 preempt_schedule_common+0x45/0xc0 kernel/sched/core.c:6098 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:255 zap_pid_ns_processes+0x271/0x660 kernel/pid_namespace.c:206 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+0x2372/0x2a60 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: 0033:0x4665e9 RSP: 002b:00007fff6b360188 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00000000ffffffff RCX: 00000000004665e9 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000043 RBP: 0000000000000000 R08: 000000000000002e R09: 00000000ffffffff R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004bfd2a R13: 000000000000000b R14: 0000000000000001 R15: 00007fff6b360380 rcu: rcu_preempt kthread timer wakeup didn't happen for 4668 jiffies! g89809 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=27276 rcu: rcu_preempt kthread starved for 4669 jiffies! g89809 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:28864 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4681 [inline] __schedule+0x93a/0x26f0 kernel/sched/core.c:5938 schedule+0xd3/0x270 kernel/sched/core.c:6017 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1881 rcu_gp_fqs_loop kernel/rcu/tree.c:1996 [inline] rcu_gp_kthread+0xd34/0x1980 kernel/rcu/tree.c:2169 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 12346 Comm: syz-executor.3 Not tainted 5.14.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:rol32 include/linux/bitops.h:108 [inline] RIP: 0010:iterate_chain_key kernel/locking/lockdep.c:419 [inline] RIP: 0010:__lock_acquire+0xc58/0x54a0 kernel/locking/lockdep.c:5003 Code: c2 06 31 ca 41 89 d7 29 d3 01 c2 41 c1 c7 08 41 31 df 44 89 f9 44 29 f8 41 01 d7 c1 c1 10 44 89 fe 31 c8 89 c1 29 c2 44 01 f8 c9 0d 31 ca 01 d0 29 d6 89 d1 48 8b 54 24 38 c1 c1 04 31 f1 48 RSP: 0018:ffffc90000007c78 EFLAGS: 00000017 RAX: 000000002a88234e RBX: 0000000051aaa3d6 RCX: 00000000e226d2df RDX: 00000000a6edff91 RSI: 000000004861506f RDI: ffffffff8fcd7ec0 RBP: ffff888148c4430a R08: 0000000000000000 R09: ffffffff8fcd48ef R10: fffffbfff1f9a91d R11: 0000000000000000 R12: ffff888148c442e8 R13: ffff888148c43880 R14: 0000000000000000 R15: 000000004861506f FS: 0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000005451f8 CR3: 0000000154ed9000 CR4: 0000000000350ef0 Call Trace: lock_acquire kernel/locking/lockdep.c:5625 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5590 seqcount_lockdep_reader_access include/linux/seqlock.h:103 [inline] timekeeping_get_delta kernel/time/timekeeping.c:252 [inline] timekeeping_get_ns kernel/time/timekeeping.c:386 [inline] ktime_get_update_offsets_now+0x14d/0x5c0 kernel/time/timekeeping.c:2298 hrtimer_update_base kernel/time/hrtimer.c:631 [inline] hrtimer_interrupt+0x142/0xa00 kernel/time/hrtimer.c:1645 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1089 [inline] __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1106 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1100 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:lock_acquire+0x1ef/0x510 kernel/locking/lockdep.c:5593 Code: d0 a6 7e 83 f8 01 0f 85 b4 02 00 00 9c 58 f6 c4 02 0f 85 9f 02 00 00 48 83 7c 24 08 00 74 01 fb 48 b8 00 00 00 00 00 fc ff df <48> 01 c3 48 c7 03 00 00 00 00 48 c7 43 08 00 00 00 00 48 8b 84 24 RSP: 0018:ffffc900022ff618 EFLAGS: 00000206 RAX: dffffc0000000000 RBX: 1ffff9200045fec5 RCX: 42f1125c69a15e59 RDX: 1ffff1102918884d RSI: 0000000000000001 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff8fcd48e7 R10: fffffbfff1f9a91c R11: 0000000000000000 R12: 0000000000000002 R13: 0000000000000000 R14: ffffffff8b97c280 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:267 [inline] rcu_read_lock include/linux/rcupdate.h:687 [inline] lock_page_memcg+0x66/0x7d0 mm/memcontrol.c:2011 page_remove_rmap+0x25/0x1480 mm/rmap.c:1345 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+0x198/0x300 mm/memory.c:1597 unmap_vmas+0x16d/0x2f0 mm/memory.c:1629 exit_mmap+0x1d0/0x620 mm/mmap.c:3201 __mmput+0x122/0x470 kernel/fork.c:1101 mmput+0x58/0x60 kernel/fork.c:1122 exit_mm kernel/exit.c:501 [inline] do_exit+0xae2/0x2a60 kernel/exit.c:812 do_group_exit+0x125/0x310 kernel/exit.c:922 get_signal+0x47f/0x2160 kernel/signal.c:2808 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: 0033:0x4665e9 Code: Unable to access opcode bytes at RIP 0x4665bf. RSP: 002b:00007f52c34aa218 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 000000000056bf88 RCX: 00000000004665e9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000056bf88 RBP: 000000000056bf80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf8c R13: 00007fff6b36005f R14: 00007f52c34aa300 R15: 0000000000022000 ---------------- Code disassembly (best guess): 0: c2 06 31 retq $0x3106 3: ca 41 89 lret $0x8941 6: d7 xlat %ds:(%rbx) 7: 29 d3 sub %edx,%ebx 9: 01 c2 add %eax,%edx b: 41 c1 c7 08 rol $0x8,%r15d f: 41 31 df xor %ebx,%r15d 12: 44 89 f9 mov %r15d,%ecx 15: 44 29 f8 sub %r15d,%eax 18: 41 01 d7 add %edx,%r15d 1b: c1 c1 10 rol $0x10,%ecx 1e: 44 89 fe mov %r15d,%esi 21: 31 c8 xor %ecx,%eax 23: 89 c1 mov %eax,%ecx 25: 29 c2 sub %eax,%edx 27: 44 01 f8 add %r15d,%eax 2a: c1 c9 0d ror $0xd,%ecx <-- trapping instruction 2d: 31 ca xor %ecx,%edx 2f: 01 d0 add %edx,%eax 31: 29 d6 sub %edx,%esi 33: 89 d1 mov %edx,%ecx 35: 48 8b 54 24 38 mov 0x38(%rsp),%rdx 3a: c1 c1 04 rol $0x4,%ecx 3d: 31 f1 xor %esi,%ecx 3f: 48 rex.W