rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P6414/1:b..l
rcu: 	(detected by 1, t=10503 jiffies, g=19549, q=669034 ncpus=2)
task:syz.1.199       state:R  running task     stack:26720 pid:6414  tgid:6412  ppid:5641   task_flags:0x40054c flags:0x08080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5387 [inline]
 __schedule+0x17b4/0x5680 kernel/sched/core.c:7188
 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7512
 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:547 [inline]
 irqentry_exit+0x14f/0x730 kernel/entry/common.c:164
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:__rcu_read_unlock+0xd/0xe0 kernel/rcu/tree_plugin.h:431
Code: df e8 57 62 85 00 eb d2 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 41 57 41 56 41 55 41 54 53 <49> bf 00 00 00 00 00 fc ff df 65 48 8b 3d b9 33 8d 11 48 8d 9f c4
RSP: 0018:ffffc9000ce87048 EFLAGS: 00000282
RAX: 1b9d7ad427019700 RBX: ffffffff90c35d01 RCX: 0000000000000046
RDX: 0000000000000001 RSI: ffffffff8e216b62 RDI: ffffffff8c28aa60
RBP: dffffc0000000000 R08: ffffc9000ce87e60 R09: 0000000000000000
R10: ffffc9000ce87198 R11: fffff520019d0e35 R12: ffffc9000ce87e70
R13: ffffc9000ce80000 R14: ffffc9000ce87148 R15: ffffffff8176e256
 rcu_read_unlock include/linux/rcupdate.h:871 [inline]
 class_rcu_destructor include/linux/rcupdate.h:1181 [inline]
 unwind_next_frame+0x1bbf/0x2550 arch/x86/kernel/unwind_orc.c:709
 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57
 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556
 __call_rcu_common kernel/rcu/tree.c:3131 [inline]
 call_rcu+0xee/0x890 kernel/rcu/tree.c:3251
 slab_free_hook mm/slub.c:2653 [inline]
 slab_free mm/slub.c:6246 [inline]
 kmem_cache_free+0x462/0x650 mm/slub.c:6373
 anon_vma_free mm/rmap.c:137 [inline]
 __put_anon_vma+0x12b/0x2d0 mm/rmap.c:2915
 put_anon_vma mm/internal.h:216 [inline]
 unlink_anon_vmas+0x58b/0x730 mm/rmap.c:536
 free_pgtables+0x836/0xb70 mm/memory.c:414
 exit_mmap+0x490/0x9e0 mm/mmap.c:1312
 __mmput+0x118/0x430 kernel/fork.c:1178
 exit_mm+0x18e/0x250 kernel/exit.c:581
 do_exit+0x6a2/0x22c0 kernel/exit.c:963
 do_group_exit+0x21b/0x2d0 kernel/exit.c:1117
 get_signal+0x1284/0x1330 kernel/signal.c:3037
 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 __do_fast_syscall_32+0x446/0x6e0 arch/x86/entry/syscall_32.c:310
 do_fast_syscall_32+0x33/0x70 arch/x86/entry/syscall_32.c:332
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf6fdf01c
RSP: 002b:00000000f53ac50c EFLAGS: 00000206 ORIG_RAX: 0000000000000172
RAX: 0000000000000028 RBX: 0000000000000005 RCX: 0000000080000340
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>