syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P4078/1:b..l
	(detected by 0, t=10502 jiffies, g=7309, q=395)
task:dhcpcd-run-hook state:R  running task     stack:26784 pid: 4078 ppid:  3241 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6376
 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6780
 irqentry_exit+0x53/0x80 kernel/entry/common.c:432
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:lock_is_held_type+0x1/0x180 kernel/locking/lockdep.c:5651
Code: 75 d6 48 c7 c7 a0 28 8b 8a 48 c7 c6 e0 28 8b 8a e8 44 f4 18 f7 0f 0b eb bf e8 ab fd ff ff 66 2e 0f 1f 84 00 00 00 00 00 90 55 <41> 57 41 56 41 55 41 54 53 48 83 ec 10 65 48 8b 04 25 28 00 00 00
RSP: 0018:ffffc9000303f7c0 EFLAGS: 00000296
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffff8880165dd940
RDX: ffff8880165dd940 RSI: 00000000ffffffff RDI: ffff888017e27290
RBP: ffff888017e27290 R08: ffffffff842fe21d R09: fffffbfff1f8e019
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff92000607f1c
R13: 0000000000000000 R14: ffff888017e15e42 R15: ffffc9000303f8e0
 lock_is_held include/linux/lockdep.h:287 [inline]
 xa_entry include/linux/xarray.h:1182 [inline]
 xas_descend+0xe2/0x3a0 lib/xarray.c:204
 xas_load+0xba/0x140 lib/xarray.c:240
 filemap_get_read_batch+0x1f6/0x900 mm/filemap.c:2341
 filemap_get_pages mm/filemap.c:2547 [inline]
 filemap_read+0x5b5/0x2980 mm/filemap.c:2634
 call_read_iter include/linux/fs.h:2166 [inline]
 new_sync_read fs/read_write.c:404 [inline]
 vfs_read+0xa93/0xe10 fs/read_write.c:485
 ksys_pread64 fs/read_write.c:675 [inline]
 __do_sys_pread64 fs/read_write.c:685 [inline]
 __se_sys_pread64 fs/read_write.c:682 [inline]
 __x64_sys_pread64+0x1a9/0x230 fs/read_write.c:682
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f2f6967da7e
RSP: 002b:00007ffdadb4c5b8 EFLAGS: 00000206 ORIG_RAX: 0000000000000011
RAX: ffffffffffffffda RBX: 00007ffdadb4cb88 RCX: 00007f2f6967da7e
RDX: 0000000000000040 RSI: 00007ffdadb4c5c0 RDI: 0000000000000003
RBP: 00007ffdadb4c990 R08: 0000000000000040 R09: 00007ffdadb4c798
R10: 0000000000000350 R11: 0000000000000206 R12: 00007ffdadb4c9a0
R13: 0000000000000003 R14: 0000000000000000 R15: 00007ffdadb4c5c0
 </TASK>
rcu: rcu_preempt kthread starved for 9727 jiffies! g7309 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R  running task     stack:27064 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6376
 schedule+0x11b/0x1f0 kernel/sched/core.c:6459
 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1914
 rcu_gp_fqs_loop+0x2bf/0x1080 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0xa4/0x360 kernel/rcu/tree.c:2145
 kthread+0x3f6/0x4f0 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </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 acpi_safe_halt drivers/acpi/processor_idle.c:108 [inline]
NMI backtrace for cpu 1 skipped: idling at acpi_idle_do_entry+0x10f/0x340 drivers/acpi/processor_idle.c:562
hrtimer: interrupt took 510019412 ns