syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P17663/1:b..l
rcu: 	(detected by 1, t=10503 jiffies, g=495213, q=870225 ncpus=2)
task:syz.9.10622     state:R  running task     stack:25824 pid:17663 tgid:17654 ppid:25297  task_flags:0x40054c flags:0x00080001
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5388 [inline]
 __schedule+0x17b4/0x5680 kernel/sched/core.c:7189
 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7513
 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:debug_lockdep_rcu_enabled+0x29/0x40 kernel/rcu/update.c:321
Code: 90 f3 0f 1e fa 31 c0 83 3d 63 5e 88 04 00 74 1d 83 3d 1a 90 88 04 00 74 14 65 48 8b 0d 58 b5 90 07 31 c0 83 b9 8c 0b 00 00 00 <0f> 94 c0 c3 cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc
RSP: 0018:ffffc9000e8b7550 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007f9f16e32d01 RCX: ffff8880a0fc1ec0
RDX: ffffffff90bbe600 RSI: 0000000000000000 RDI: ffffc9000e8b7630
RBP: dffffc0000000000 R08: 0000000000000022 R09: ffffffff8e95cd60
R10: ffffc9000e8b7678 R11: ffffffff81b0e840 R12: 00007f9f17c68028
R13: ffffc9000e8b0000 R14: ffffc9000e8b7628 R15: ffffffff8176f256
 rcu_read_unlock include/linux/rcupdate.h:867 [inline]
 class_rcu_destructor include/linux/rcupdate.h:1181 [inline]
 unwind_next_frame+0x1b6d/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
 save_stack+0x122/0x230 mm/page_owner.c:165
 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:320
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1402 [inline]
 __free_frozen_pages+0xbc7/0xd30 mm/page_alloc.c:2943
 vfree+0x1d1/0x2f0 mm/vmalloc.c:3472
 kcov_put kernel/kcov.c:442 [inline]
 kcov_close+0x28/0x50 kernel/kcov.c:543
 __fput+0x44f/0xa60 fs/file_table.c:510
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x70f/0x22c0 kernel/exit.c:975
 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_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9f16d9cdd9
RSP: 002b:00007f9f17c68028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: 0000000000000000 RBX: 00007f9f17016180 RCX: 00007f9f16d9cdd9
RDX: 0000200000000040 RSI: 00000000400454ca RDI: 000000000000000b
RBP: 00007f9f16e32d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9f17016218 R14: 00007f9f17016180 R15: 00007f9f1713fa48
 </TASK>