syzbot

rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (10499 ticks this GP) idle=dfe/1/0x4000000000000002 softirq=11756/11756 fqs=38 
	(t=10500 jiffies g=6133 q=796)
rcu: rcu_preempt kthread starved for 10421 jiffies! g6133 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: RCU grace-period kthread stack dump:
rcu_preempt     R  running task    29032    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: 8097 Comm: syz-executor.0 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+0x168/0x190 include/linux/memcontrol.h:655
Code: c7 28 96 0a 89 e8 a8 9e 69 00 48 83 3d c8 21 c2 07 00 74 2d e8 99 27 2e 00 4c 89 ff 57 9d 0f 1f 44 00 00 5b 41 5c 41 5e 41 5f <5d> c3 e8 81 27 2e 00 0f 0b e8 7a 27 2e 00 0f 0b e8 73 27 2e 00 0f
RSP: 0018:ffffc90002257b00 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: ffffffff81487433 RBX: ffff8880a93a1608 RCX: 0000000000040000
RDX: ffffc90001ee9000 RSI: 000000000003ffff RDI: 0000000000040000
RBP: ffffc90002257b00 R08: 000000000003a768 R09: ffffed10152e4f47
R10: ffffed10152e4f47 R11: 0000000000000000 R12: ffff8880a93a16a0
R13: dffffc0000000000 R14: 1ffff110152742d4 R15: ffff8880a9727a28
 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_notrace+0xdb/0x120 kernel/sched/core.c:4309
 ___preempt_schedule_notrace+0x16/0x27 arch/x86/entry/thunk_64.S:51
 rcu_is_watching+0x82/0xa0 kernel/rcu/tree.c:923
 rcu_read_unlock include/linux/rcupdate.h:667 [inline]
 memcg_kmem_get_cache+0x301/0x590 mm/memcontrol.c:2808
 slab_pre_alloc_hook mm/slab.h:572 [inline]
 slab_alloc mm/slab.c:3306 [inline]
 kmem_cache_alloc_trace+0x8c/0x2f0 mm/slab.c:3549
 kmalloc include/linux/slab.h:556 [inline]
 kzalloc include/linux/slab.h:670 [inline]
 alloc_pipe_info+0xeb/0x470 fs/pipe.c:696
 get_pipe_inode fs/pipe.c:776 [inline]
 create_pipe_files+0x85/0x6c0 fs/pipe.c:808
 __do_pipe_flags+0x4c/0x210 fs/pipe.c:847
 do_pipe2+0x41/0x230 fs/pipe.c:895
 __do_sys_pipe fs/pipe.c:918 [inline]
 __se_sys_pipe fs/pipe.c:916 [inline]
 __x64_sys_pipe+0x3a/0x40 fs/pipe.c:916
 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45a679
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:00007f5780a6ac78 EFLAGS: 00000246 ORIG_RAX: 0000000000000016
RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 000000000045a679
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000100
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f5780a6b6d4
R13: 00000000004fa2a7 R14: 00000000004df950 R15: 00000000ffffffff