syzbot

rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-...!: (10499 ticks this GP) idle=aea/1/0x4000000000000002 softirq=11426/11428 fqs=2 
	(t=10501 jiffies g=6177 q=85)
rcu: rcu_preempt kthread starved for 10498 jiffies! g6177 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
rcu: RCU grace-period kthread stack dump:
rcu_preempt     R  running task    29104    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 0
CPU: 0 PID: 8206 Comm: blkid Not tainted 5.4.0-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:1514 [inline]
 __hrtimer_run_queues+0x403/0x840 kernel/time/hrtimer.c:1576
 hrtimer_interrupt+0x38c/0xda0 kernel/time/hrtimer.c:1638
 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:mod_memcg_page_state+0x16/0x190 include/linux/memcontrol.h:653
Code: 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f 5d c3 0f 1f 44 00 00 55 48 89 e5 41 57 41 56 41 54 53 41 89 f6 48 89 fb e8 da 28 2e 00 <48> 83 c3 38 48 89 d8 48 c1 e8 03 49 bc 00 00 00 00 00 fc ff df 42
RSP: 0018:ffffc900022277d8 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13
RAX: ffffffff81487326 RBX: ffffea0001b08e40 RCX: ffff88809a652600
RDX: 0000000000000000 RSI: 00000000fffffffc RDI: ffffea0001b08e40
RBP: ffffc900022277f8 R08: dffffc0000000000 R09: fffffbfff1287025
R10: fffffbfff1287025 R11: 0000000000000000 R12: ffff88806c15d3a0
R13: dffffc0000000000 R14: 00000000fffffffc R15: ffff88806c2754e8
 free_thread_stack+0x168/0x590 kernel/fork.c:280
 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_irq+0xc1/0x140 kernel/sched/core.c:4338
 retint_kernel+0x1b/0x2b
RIP: 0010:arch_local_save_flags arch/x86/include/asm/paravirt.h:747 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/paravirt.h:769 [inline]
RIP: 0010:lock_release+0x6a/0x780 kernel/locking/lockdep.c:4499
Code: 89 f3 48 c1 eb 03 8a 04 13 84 c0 0f 85 9d 04 00 00 41 83 3e 00 0f 85 71 04 00 00 48 c7 c0 20 96 0a 89 48 c1 e8 03 80 3c 10 00 <74> 16 48 c7 c7 20 96 0a 89 e8 d8 5f 56 00 48 ba 00 00 00 00 00 fc
RSP: 0018:ffffc90002227a50 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 1ffffffff12152c4 RBX: 1ffff110134ca5d2 RCX: ffff88809a652600
RDX: dffffc0000000000 RSI: ffffffff81a505d4 RDI: ffff8880966e77f0
RBP: ffffc90002227ad0 R08: ffffffff81a12273 R09: ffffed1012cdcef3
R10: ffffed1012cdcef3 R11: 0000000000000000 R12: ffff88809a652600
R13: ffffffff81a505d4 R14: ffff88809a652e94 R15: ffff8880966e77f0
 up_read+0x15/0x20 kernel/locking/rwsem.c:1576
 anon_vma_unlock_read include/linux/rmap.h:135 [inline]
 validate_mm+0x154/0x9b0 mm/mmap.c:410
 __vma_adjust+0x2280/0x2390 mm/mmap.c:984
 __split_vma+0x356/0x490 include/linux/mm.h:2261
 split_vma+0x7a/0xd0 mm/mmap.c:2714
 mprotect_fixup+0x6ef/0x790 mm/mprotect.c:413
 do_mprotect_pkey+0x6c2/0x8d0 mm/mprotect.c:553
 __do_sys_mprotect mm/mprotect.c:578 [inline]
 __se_sys_mprotect mm/mprotect.c:575 [inline]
 __x64_sys_mprotect+0x80/0x90 mm/mprotect.c:575
 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f553ee57447
Code: 73 01 c3 48 8d 0d 5d ad 20 00 31 d2 48 29 c2 89 11 48 83 c8 ff eb eb 90 90 90 90 90 90 90 90 90 90 90 90 b8 0a 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8d 0d 2d ad 20 00 31 d2 48 29 c2 89
RSP: 002b:00007ffc10fef388 EFLAGS: 00000206 ORIG_RAX: 000000000000000a
RAX: ffffffffffffffda RBX: 00007f553f05f9a8 RCX: 00007f553ee57447
RDX: 0000000000000000 RSI: 00000000001ff000 RDI: 00007f553ea11000
RBP: 00007ffc10fef6e0 R08: 0000000000000003 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000206 R12: 00007ffc10fef7c8
R13: 0000000000000002 R14: 0000000000000030 R15: 00007ffc10fef3d0