syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P15484/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=66181, q=745004 ncpus=2)
task:syz.2.1761      state:R  running task     stack:26984 pid:15484 tgid:15481 ppid:8458   task_flags:0x40054c flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7288
 irqentry_exit+0x6f/0x90 kernel/entry/common.c:197
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:memset+0xf/0x20 arch/x86/lib/memset_64.S:38
Code: 44 88 1f e9 ae a4 96 f5 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 49 89 f9 40 88 f0 48 89 d1 <f3> aa 4c 89 c8 e9 82 a4 96 f5 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc9000b877530 EFLAGS: 00000202
RAX: 1ffff9200170ee00 RBX: ffffc9000b877640 RCX: 000000000000000b
RDX: 0000000000000010 RSI: 0000000000000000 RDI: ffffc9000b87765d
RBP: dffffc0000000000 R08: ffffc9000b877667 R09: ffffc9000b877658
R10: dffffc0000000000 R11: fffff5200170eecd R12: ffffc9000b877980
R13: ffffc9000b877658 R14: ffffc9000b877608 R15: ffffc9000b877650
 unwind_next_frame+0xc98/0x2390 arch/x86/kernel/unwind_orc.c:592
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 save_stack+0xf5/0x1f0 mm/page_owner.c:156
 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:308
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1395 [inline]
 __free_frozen_pages+0xbc4/0xd30 mm/page_alloc.c:2895
 vfree+0x25a/0x400 mm/vmalloc.c:3434
 kcov_put kernel/kcov.c:439 [inline]
 kcov_close+0x28/0x50 kernel/kcov.c:535
 __fput+0x44c/0xa70 fs/file_table.c:468
 task_work_run+0x1d4/0x260 kernel/task_work.c:227
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x6b5/0x2300 kernel/exit.c:961
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1102
 get_signal+0x1286/0x1340 kernel/signal.c:3034
 arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x75/0x110 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_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f849fb8ebe9
RSP: 002b:00007f84a0a13038 EFLAGS: 00000246 ORIG_RAX: 00000000000000cb
RAX: 0000000000000000 RBX: 00007f849fdb6180 RCX: 00007f849fb8ebe9
RDX: 00002000000002c0 RSI: 0000000000000008 RDI: 0000000000000000
RBP: 00007f849fc11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f849fdb6218 R14: 00007f849fdb6180 R15: 00007ffde364d448
 </TASK>