rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5838/1:b..l P11965/1:b..l P9511/1:b..l P14293/1:b..l
rcu: 	(detected by 0, t=10503 jiffies, g=87789, q=1029489 ncpus=2)
task:syz.4.2250      state:R  running task     stack:26856 pid:14293 tgid:14293 ppid:5838   task_flags:0x40044c flags:0x10080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5325 [inline]
 __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7113
 preempt_schedule+0xae/0xc0 kernel/sched/core.c:7137
 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
 _raw_spin_unlock+0x3f/0x50 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:391 [inline]
 zap_pte_range mm/memory.c:1884 [inline]
 zap_pmd_range mm/memory.c:1946 [inline]
 zap_pud_range mm/memory.c:1975 [inline]
 zap_p4d_range mm/memory.c:1996 [inline]
 unmap_page_range+0x3a7f/0x4370 mm/memory.c:2017
 unmap_single_vma mm/memory.c:2060 [inline]
 unmap_vmas+0x399/0x580 mm/memory.c:2104
 exit_mmap+0x240/0xb40 mm/mmap.c:1280
 __mmput+0x118/0x430 kernel/fork.c:1133
 exit_mm+0x1da/0x2c0 kernel/exit.c:582
 do_exit+0x648/0x2300 kernel/exit.c:954
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1107
 get_signal+0x1285/0x1340 kernel/signal.c:3034
 arch_do_signal_or_restart+0xa0/0x790 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x72/0x130 kernel/entry/common.c:40
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 __do_fast_syscall_32+0x1f4/0x2b0 arch/x86/entry/syscall_32.c:309
 do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:331
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf704d539
RSP: 002b:00000000f543d460 EFLAGS: 00000206 ORIG_RAX: 000000000000010b
RAX: fffffffffffffdfc RBX: 0000000000000000 RCX: 0000000000000000
RDX: 00000000f543d494 RSI: 00000000f543d48c RDI: 00000000f543d494
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
task:syz.4.927       state:R  running task     stack:26856 pid:9511  tgid:9511  ppid:5838   task_flags:0x40044c flags:0x10080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5325 [inline]
 __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7256
 irqentry_exit+0x6f/0x90 kernel/entry/common.c:211
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_release+0x2b5/0x3e0 kernel/locking/lockdep.c:5893
Code: 51 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 75 56 f7 c3 00 02 00 00 74 01 fb 65 48 8b 05 ab fa f3 10 <48> 3b 44 24 28 0f 85 8b 00 00 00 48 83 c4 30 5b 41 5c 41 5d 41 5e
RSP: 0018:ffffc90003e770d0 EFLAGS: 00000206
RAX: 309af8fccdb29100 RBX: 0000000000000206 RCX: 309af8fccdb29100
RDX: 0000000000000002 RSI: ffffffff8d9d457d RDI: ffffffff8bc07360
RBP: ffff88801c710b80 R08: ffffc90003e77c60 R09: 0000000000000000
R10: ffffc90003e77258 R11: fffff520007cee4d R12: 0000000000000002
R13: 0000000000000002 R14: ffffffff8e13d2e0 R15: ffff88801c710000
 rcu_lock_release include/linux/rcupdate.h:341 [inline]
 rcu_read_unlock include/linux/rcupdate.h:897 [inline]
 class_rcu_destructor include/linux/rcupdate.h:1195 [inline]
 unwind_next_frame+0x19a9/0x2390 arch/x86/kernel/unwind_orc.c:680
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:56 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
 __kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:587
 kasan_save_free_info mm/kasan/kasan.h:406 [inline]
 poison_slab_object mm/kasan/common.c:252 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:284
 kasan_slab_free include/linux/kasan.h:234 [inline]
 slab_free_hook mm/slub.c:2530 [inline]
 slab_free mm/slub.c:6619 [inline]
 kmem_cache_free+0x19b/0x690 mm/slub.c:6729
 anon_vma_chain_free mm/rmap.c:146 [inline]
 unlink_anon_vmas+0x2cc/0x670 mm/rmap.c:420
 free_pgtables+0x57a/0x9c0 mm/memory.c:398
 exit_mmap+0x43c/0xb40 mm/mmap.c:1291
 __mmput+0x118/0x430 kernel/fork.c:1133
 exit_mm+0x1da/0x2c0 kernel/exit.c:582
 do_exit+0x648/0x2300 kernel/exit.c:954
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1107
 get_signal+0x1285/0x1340 kernel/signal.c:3034
 arch_do_signal_or_restart+0xa0/0x790 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x72/0x130 kernel/entry/common.c:40
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 __do_fast_syscall_32+0x1f4/0x2b0 arch/x86/entry/syscall_32.c:309
 do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:331
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf704d539
RSP: 002b:00000000f543d460 EFLAGS: 00000206 ORIG_RAX: 000000000000010b
RAX: fffffffffffffdfc RBX: 0000000000000000 RCX: 0000000000000000
RDX: 00000000f543d494 RSI: 00000000f543d48c RDI: 00000000f543d494
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
task:syz.4.1557      state:R  running task     stack:26856 pid:11965 tgid:11965 ppid:5838   task_flags:0x40044c flags:0x10080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5325 [inline]
 __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7113
 preempt_schedule+0xae/0xc0 kernel/sched/core.c:7137
 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
 _raw_spin_unlock+0x3f/0x50 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:391 [inline]
 zap_pte_range mm/memory.c:1884 [inline]
 zap_pmd_range mm/memory.c:1946 [inline]
 zap_pud_range mm/memory.c:1975 [inline]
 zap_p4d_range mm/memory.c:1996 [inline]
 unmap_page_range+0x3a7f/0x4370 mm/memory.c:2017
 unmap_single_vma mm/memory.c:2060 [inline]
 unmap_vmas+0x399/0x580 mm/memory.c:2104
 exit_mmap+0x240/0xb40 mm/mmap.c:1280
 __mmput+0x118/0x430 kernel/fork.c:1133
 exit_mm+0x1da/0x2c0 kernel/exit.c:582
 do_exit+0x648/0x2300 kernel/exit.c:954
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1107
 get_signal+0x1285/0x1340 kernel/signal.c:3034
 arch_do_signal_or_restart+0xa0/0x790 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x72/0x130 kernel/entry/common.c:40
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 __do_fast_syscall_32+0x1f4/0x2b0 arch/x86/entry/syscall_32.c:309
 do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:331
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf704d539
RSP: 002b:00000000f543d460 EFLAGS: 00000206 ORIG_RAX: 000000000000010b
RAX: fffffffffffffdfc RBX: 0000000000000000 RCX: 0000000000000000
RDX: 00000000f543d494 RSI: 00000000f543d48c RDI: 00000000f543d494
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
task:syz-executor    state:R  running task     stack:20152 pid:5838  tgid:5838  ppid:1      task_flags:0x40054c flags:0x10080003
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5325 [inline]
 __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7113
 preempt_schedule+0xae/0xc0 kernel/sched/core.c:7137
 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
 __raw_read_unlock include/linux/rwlock_api_smp.h:233 [inline]
 _raw_read_unlock+0x3f/0x50 kernel/locking/spinlock.c:260
 zap_pid_ns_processes+0x2c4/0x5f0 kernel/pid_namespace.c:233
 find_child_reaper kernel/exit.c:623 [inline]
 forget_original_parent kernel/exit.c:707 [inline]
 exit_notify kernel/exit.c:744 [inline]
 do_exit+0x1ee7/0x2300 kernel/exit.c:978
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1107
 get_signal+0x1285/0x1340 kernel/signal.c:3034
 arch_do_signal_or_restart+0xa0/0x790 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x72/0x130 kernel/entry/common.c:40
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 __do_fast_syscall_32+0x1f4/0x2b0 arch/x86/entry/syscall_32.c:309
 do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:331
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf704d539
RSP: 002b:00000000f753fcb0 EFLAGS: 00000206 ORIG_RAX: 000000000000010b
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 00000000f753fce4 RSI: 00000000f753fcdc RDI: 00000000f753fce4
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>