syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5657/1:b..l
	(detected by 1, t=10502 jiffies, g=13877, q=76)
task:syz.4.406       state:R  running task     stack:25008 pid: 5657 ppid:  4186 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6799
 irqentry_exit+0x63/0x70 kernel/entry/common.c:432
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:lock_is_held_type+0x13a/0x190 kernel/locking/lockdep.c:5671
Code: 75 40 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 75 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
RSP: 0018:ffffc90005c5f668 EFLAGS: 00000206
RAX: d757bec436d6ea00 RBX: ffff8880220e8000 RCX: d757bec436d6ea00
RDX: 0000000000000002 RSI: ffffffff8a2b3a20 RDI: ffffffff8a79f740
RBP: 0000000000000000 R08: ffff8880220e8000 R09: 0000000000000002
R10: 0000000000000003 R11: 0000000000000002 R12: 0000000000000002
R13: 0000000000000246 R14: ffff888022f22288 R15: ffff8880220e8b40
 lock_is_held include/linux/lockdep.h:287 [inline]
 xa_head include/linux/xarray.h:1181 [inline]
 xas_start+0x1e5/0x770 lib/xarray.c:188
 xas_load lib/xarray.c:233 [inline]
 xas_find+0x154/0xab0 lib/xarray.c:1249
 first_map_page mm/filemap.c:3288 [inline]
 filemap_map_pages+0x21d/0x13b0 mm/filemap.c:3314
 do_fault_around mm/memory.c:4243 [inline]
 do_read_fault mm/memory.c:4258 [inline]
 do_fault mm/memory.c:4392 [inline]
 handle_pte_fault mm/memory.c:4650 [inline]
 __handle_mm_fault mm/memory.c:4785 [inline]
 handle_mm_fault+0x25bc/0x4410 mm/memory.c:4883
 faultin_page mm/gup.c:976 [inline]
 __get_user_pages+0x94b/0x11e0 mm/gup.c:1197
 populate_vma_page_range+0x213/0x290 mm/gup.c:1529
 __mm_populate+0x275/0x3b0 mm/gup.c:1638
 mm_populate include/linux/mm.h:2646 [inline]
 vm_mmap_pgoff+0x212/0x2d0 mm/util.c:556
 ksys_mmap_pgoff+0x140/0x790 mm/mmap.c:1635
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fac3b575f79
RSP: 002b:00007fac397d0028 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007fac3b7effa0 RCX: 00007fac3b575f79
RDX: b635773f04ebbeee RSI: 0000000000b36000 RDI: 0000200000000000
RBP: 00007fac3b60c7e0 R08: ffffffffffffffff R09: 0000000000000000
R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fac3b7f0038 R14: 00007fac3b7effa0 R15: 00007ffea4f4d5b8
 </TASK>
rcu: rcu_preempt kthread starved for 10537 jiffies! g13877 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0
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:28016 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6799
 irqentry_exit+0x63/0x70 kernel/entry/common.c:432
 asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:681
RIP: 0010:rcu_gp_fqs_check_wake kernel/rcu/tree.c:1899 [inline]
RIP: 0010:rcu_gp_fqs_loop+0x2af/0x11d0 kernel/rcu/tree.c:1972
Code: 37 76 f4 ff 41 f6 c6 04 75 34 44 0f b7 35 89 57 cc 0a 41 f6 c6 02 75 26 48 83 3d 23 53 cc 0a 00 75 0a 48 83 3d 99 53 cc 0a 00 <74> 12 48 85 db 74 0d 48 89 df e8 12 63 5f 08 48 89 c3 eb ad 48 c7
RSP: 0018:ffffc90000d47ca0 EFLAGS: 00000286
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: ffffffff8a2b2780 RDI: 00000000ffffffff
RBP: ffffc90000d47df0 R08: ffffffff8c323363 R09: 1ffffffff186466c
R10: dffffc0000000000 R11: fffffbfff186466d R12: ffff88813fe1e600
R13: 1ffffffff1801e30 R14: 0000000000000000 R15: ffffc90000d47d68
 rcu_gp_kthread+0x9b/0x370 kernel/rcu/tree.c:2145
 kthread+0x436/0x520 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 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
NMI backtrace for cpu 0 skipped: idling at default_idle+0xb/0x10 arch/x86/kernel/process.c:729