rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-...!: (10499 ticks this GP) idle=0fe/1/0x4000000000000002 softirq=10202/10202 fqs=60 
	(t=10500 jiffies g=6525 q=1406)
rcu: rcu_preempt kthread starved for 10360 jiffies! g6525 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
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 0
CPU: 0 PID: 8271 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:memcg_kmem_uncharge include/linux/memcontrol.h:1402 [inline]
RIP: 0010:free_thread_stack+0x124/0x590 kernel/fork.c:284
Code: ff 48 c1 e8 06 48 83 e0 c0 48 bf 00 00 00 00 00 ea ff ff 48 01 c7 be 03 00 00 00 e8 06 a2 60 00 e9 5d 04 00 00 e8 5c 2d 2e 00 <48> 89 df 31 f6 e8 42 af 6e 00 43 80 3c 2e 00 74 08 4c 89 e7 e8 43
RSP: 0018:ffffc900024976b8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: ffffffff81486ea4 RBX: ffffea00028dadc0 RCX: 0000000000040000
RDX: ffffc90001f49000 RSI: 000000000003ffff RDI: 0000000000040000
RBP: ffffc900024976f0 R08: 000000000003a768 R09: ffffed1014ec2eb7
R10: ffffed1014ec2eb7 R11: 0000000000000000 R12: ffff8880a2784e20
R13: dffffc0000000000 R14: 1ffff110144f09c4 R15: ffff8880a76175a8
 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:rcu_is_watching+0x6f/0xa0 kernel/rcu/tree.c:923
Code: 03 00 49 03 1e 48 89 df be 04 00 00 00 e8 d9 30 4e 00 48 89 d8 48 c1 e8 03 42 8a 04 38 84 c0 75 1e 8b 03 65 ff 0d 8d 6d 9e 7e <74> 0c 83 e0 02 d1 e8 5b 41 5e 41 5f 5d c3 e8 67 b0 9c ff eb ed 89
RSP: 0018:ffffc90002497908 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13
RAX: 00000000000070fe RBX: ffff8880aec37e60 RCX: ffffffff8163b027
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff8880aec37e60
RBP: ffffc90002497920 R08: dffffc0000000000 R09: ffffed1015d86fcd
R10: ffffed1015d86fcd R11: 0000000000000000 R12: 1ffff92000492f2b
R13: dffffc0000000000 R14: ffffffff88dff0c0 R15: dffffc0000000000
 rcu_read_unlock include/linux/rcupdate.h:667 [inline]
 find_get_entry+0x758/0x850 mm/filemap.c:1557
 pagecache_get_page+0x5b/0xd30 mm/filemap.c:1635
 grab_cache_page_write_begin+0x5c/0xa0 mm/filemap.c:3259
 ext4_da_write_begin+0x48f/0xf70 fs/ext4/inode.c:2965
 generic_perform_write+0x25d/0x4e0 mm/filemap.c:3309
 ext4_buffered_write_iter+0x467/0x5f0 fs/ext4/file.c:252
 ext4_file_write_iter+0x546/0x1f50 include/linux/fs.h:796
 call_write_iter include/linux/fs.h:1902 [inline]
 new_sync_write fs/read_write.c:483 [inline]
 __vfs_write+0x5a1/0x740 fs/read_write.c:496
 vfs_write+0x275/0x590 fs/read_write.c:558
 ksys_write+0x117/0x220 fs/read_write.c:611
 __do_sys_write fs/read_write.c:623 [inline]
 __se_sys_write fs/read_write.c:620 [inline]
 __x64_sys_write+0x7b/0x90 fs/read_write.c:620
 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:00007f54aacc2c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045a679
RDX: 00000000fffffe38 RSI: 0000000020000080 RDI: 0000000000000006
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f54aacc36d4
R13: 00000000004cbac0 R14: 00000000004e56b0 R15: 00000000ffffffff