syzbot

rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (1 GPs behind) idle=ace/1/0x4000000000000002 softirq=13307/13308 fqs=147 
	(t=10501 jiffies g=7125 q=76)
rcu: rcu_preempt kthread starved for 10208 jiffies! g7125 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: RCU grace-period kthread stack dump:
rcu_preempt     R  running task    28984    10      2 0x80004000
Call Trace:
 context_switch kernel/sched/core.c:3385 [inline]
 __schedule+0x9a0/0xcc0 kernel/sched/core.c:4081
 schedule+0x181/0x210 kernel/sched/core.c:4155
 schedule_timeout+0x14f/0x240 kernel/time/timer.c:1895
 rcu_gp_fqs_loop kernel/rcu/tree.c:1661 [inline]
 rcu_gp_kthread+0xed8/0x1770 kernel/rcu/tree.c:1821
 kthread+0x332/0x350 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
NMI backtrace for cpu 1
CPU: 1 PID: 8511 Comm: syz-executor.0 Not tainted 5.5.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1fb/0x318 lib/dump_stack.c:118
 nmi_cpu_backtrace+0xaf/0x1a0 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x174/0x290 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x10/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_dump_cpu_stacks+0x15a/0x220 kernel/rcu/tree_stall.h:254
 print_cpu_stall kernel/rcu/tree_stall.h:455 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:529 [inline]
 rcu_pending kernel/rcu/tree.c:2827 [inline]
 rcu_sched_clock_irq+0xe25/0x1ad0 kernel/rcu/tree.c:2271
 update_process_times+0x12d/0x180 kernel/time/timer.c:1726
 tick_sched_handle kernel/time/tick-sched.c:167 [inline]
 tick_sched_timer+0x263/0x420 kernel/time/tick-sched.c:1310
 __run_hrtimer kernel/time/hrtimer.c:1517 [inline]
 __hrtimer_run_queues+0x403/0x840 kernel/time/hrtimer.c:1579
 hrtimer_interrupt+0x38c/0xda0 kernel/time/hrtimer.c:1641
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline]
 smp_apic_timer_interrupt+0x109/0x280 arch/x86/kernel/apic/apic.c:1135
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
 </IRQ>
RIP: 0010:__memcg_kmem_uncharge+0xa/0x1a0 mm/memcontrol.c:2908
Code: 74 12 48 81 c3 08 02 00 00 48 89 df 4c 89 f6 e8 8c 85 ff ff 5b 41 5e 5d c3 0f 1f 80 00 00 00 00 55 48 89 e5 41 57 41 56 41 55 <41> 54 53 50 89 f3 49 89 fc 48 b8 00 00 00 00 00 fc ff df 4c 8d 77
RSP: 0018:ffffc90002ac76c0 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: ffffffff81489244 RBX: ffffea00027fbb80 RCX: 0000000000040000
RDX: ffffc90002179000 RSI: 0000000000000000 RDI: ffffea00027fbb80
RBP: ffffc90002ac76d8 R08: dffffc0000000000 R09: fffffbfff124248a
R10: fffffbfff124248a R11: 0000000000000000 R12: ffff8880a0e81920
R13: dffffc0000000000 R14: 1ffff110141d0324 R15: ffff8880a2903878
 memcg_kmem_uncharge include/linux/memcontrol.h:1402 [inline]
 free_thread_stack+0x12e/0x590 kernel/fork.c:284
 release_task_stack kernel/fork.c:440 [inline]
 put_task_stack+0xa3/0x130 kernel/fork.c:451
 finish_task_switch+0x3f1/0x550 kernel/sched/core.c:3256
 context_switch kernel/sched/core.c:3388 [inline]
 __schedule+0x9a8/0xcc0 kernel/sched/core.c:4081
 preempt_schedule_common kernel/sched/core.c:4236 [inline]
 preempt_schedule+0xdb/0x120 kernel/sched/core.c:4261
 ___preempt_schedule+0x16/0x18 arch/x86/entry/thunk_64.S:50
 __kunmap_atomic include/linux/highmem.h:102 [inline]
 clear_highpage include/linux/highmem.h:215 [inline]
 kernel_init_free_pages mm/page_alloc.c:1125 [inline]
 prep_new_page+0x161/0x2e0 mm/page_alloc.c:2171
 get_page_from_freelist+0x850/0xaa0 mm/page_alloc.c:3695
 __alloc_pages_nodemask+0x264/0x5d0 mm/page_alloc.c:4756
 __alloc_pages include/linux/gfp.h:496 [inline]
 __alloc_pages_node include/linux/gfp.h:509 [inline]
 alloc_pages_vma+0x94a/0xd50 mm/mempolicy.c:2151
 do_huge_pmd_anonymous_page+0x883/0xe50 mm/huge_memory.c:758
 create_huge_pmd mm/memory.c:3888 [inline]
 __handle_mm_fault mm/memory.c:4098 [inline]
 handle_mm_fault+0x2017/0x2890 mm/memory.c:4164
 do_user_addr_fault+0x589/0xaf0 arch/x86/mm/fault.c:1441
 __do_page_fault+0xd3/0x1f0 arch/x86/mm/fault.c:1506
 do_page_fault+0x99/0xb0 arch/x86/mm/fault.c:1530
 page_fault+0x39/0x40 arch/x86/entry/entry_64.S:1203
RIP: 0010:__put_user_4+0x1c/0x30 arch/x86/lib/putuser.S:70
Code: 1f 00 c3 90 66 2e 0f 1f 84 00 00 00 00 00 65 48 8b 1c 25 c0 1d 02 00 48 8b 9b d0 14 00 00 48 83 eb 03 48 39 d9 73 4a 0f 1f 00 <89> 01 31 c0 0f 1f 00 c3 66 90 66 2e 0f 1f 84 00 00 00 00 00 65 48
RSP: 0018:ffffc90002ac7e68 EFLAGS: 00010293
RAX: 0000000000000003 RBX: 00007fffffffeffd RCX: 0000000020000280
RDX: dffffc0000000000 RSI: ffff88808cb108f8 RDI: 0000000000000286
RBP: ffffc90002ac7ed8 R08: dffffc0000000000 R09: fffffbfff12c962d
R10: fffffbfff12c962d R11: 0000000000000000 R12: 0000000000000003
R13: 0000000020000280 R14: 0000000000000004 R15: 0000000000000000
 __do_sys_socketpair net/socket.c:1624 [inline]
 __se_sys_socketpair net/socket.c:1621 [inline]
 __x64_sys_socketpair+0x9b/0xb0 net/socket.c:1621
 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45af49
Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f3f0e6f8c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000035
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 000000000045af49
RDX: 0000000000000000 RSI: 0000000000000003 RDI: 0000000000000001
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000020000280 R11: 0000000000000246 R12: 00007f3f0e6f96d4
R13: 00000000004cbb07 R14: 00000000004e6468 R15: 00000000ffffffff