syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P14099/1:b..l
	(detected by 0, t=10502 jiffies, g=101077, q=109 ncpus=2)
task:syz.1.2033      state:R  running task     stack:22640 pid:14099 ppid:7964   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6874
 irqentry_exit+0x63/0x70 kernel/entry/common.c:439
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:lock_is_held_type+0x150/0x190 kernel/locking/lockdep.c:5710
Code: 46 41 f7 c5 00 02 00 00 74 01 fb 65 48 8b 04 25 28 00 00 00 48 3b 44 24 08 75 3c 89 e8 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f <5d> c3 0f 0b 48 c7 c7 20 11 8c 8a e8 00 12 00 00 65 c7 05 25 80 d4
RSP: 0018:ffffc90004f0f0d8 EFLAGS: 00000282
RAX: 0000000000000001 RBX: dffffc0000000000 RCX: 11bf8fa736da1300
RDX: ffff88802638d940 RSI: ffffffff8a8c22a0 RDI: ffffffff8adf13a0
RBP: 0000000000000001 R08: ffff88802638d940 R09: 0000000000000002
R10: 0000000000000003 R11: 0000000000000000 R12: 1ffff920009e1e3e
R13: ffffc90004f0f1f2 R14: 0000000000000000 R15: ffffc90004f0f1f8
 xa_entry include/linux/xarray.h:1198 [inline]
 xas_find+0x5ad/0xab0 lib/xarray.c:1269
 find_get_entry mm/filemap.c:2031 [inline]
 find_lock_entries+0x1c8/0xbb0 mm/filemap.c:2123
 shmem_undo_range+0x288/0x20c0 mm/shmem.c:925
 shmem_truncate_range mm/shmem.c:1062 [inline]
 shmem_evict_inode+0x25b/0xa80 mm/shmem.c:1171
 evict+0x4c9/0x8d0 fs/inode.c:705
 __dentry_kill+0x431/0x650 fs/dcache.c:611
 dentry_kill+0xb8/0x290 fs/dcache.c:-1
 dput+0xfa/0x1d0 fs/dcache.c:918
 __fput+0x5e0/0x920 fs/file_table.c:328
 task_work_run+0x1d0/0x260 kernel/task_work.c:203
 exit_task_work include/linux/task_work.h:39 [inline]
 do_exit+0x982/0x2480 kernel/exit.c:880
 do_group_exit+0x217/0x2d0 kernel/exit.c:1022
 get_signal+0x1272/0x1350 kernel/signal.c:2871
 arch_do_signal_or_restart+0xc4/0x1350 arch/x86/kernel/signal.c:871
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 irqentry_exit_to_user_mode+0x5/0x30 kernel/entry/common.c:316
 exc_general_protection+0x164/0x1f0 arch/x86/kernel/traps.c:729
 asm_exc_general_protection+0x22/0x30 arch/x86/include/asm/idtentry.h:602
RIP: 0033:0x7f825739c821
RSP: 002b:00002000000000e0 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00007f8257615fa0 RCX: 00007f825739c819
RDX: 0000200000000100 RSI: 00002000000000e0 RDI: 0000000000000200
RBP: 00007f8257432c91 R08: 0000200000000180 R09: 0000200000000180
R10: 0000200000000140 R11: 0000000000000206 R12: 0000000000000000
R13: 00007f8257616038 R14: 00007f8257615fa0 R15: 00007ffd95826f88
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10287 jiffies! g101077 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=68321
rcu: rcu_preempt kthread starved for 10288 jiffies! g101077 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=1
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:27288 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
 schedule+0xb9/0x180 kernel/sched/core.c:6638
 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2168
 rcu_gp_fqs_loop+0x303/0x1340 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0x99/0x3b0 kernel/rcu/tree.c:1905
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
NMI backtrace for cpu 1 skipped: idling at default_idle+0xb/0x10 arch/x86/kernel/process.c:741
hrtimer: interrupt took 677566162 ns