syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P6003/1:b..l
	(detected by 0, t=10502 jiffies, g=21317, q=202)
task:syz.2.497       state:R  running task     stack:26336 pid: 6003 ppid:  5749 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5027 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6373
 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6777
 irqentry_exit+0x53/0x80 kernel/entry/common.c:432
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:lock_acquire+0x252/0x4f0 kernel/locking/lockdep.c:5627
Code: 2b 00 74 08 4c 89 f7 e8 0c 75 67 00 f6 44 24 61 02 0f 85 84 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25
RSP: 0018:ffffc90002e97540 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 1ffff920005d2eb4 RCX: 1ffff920005d2e54
RDX: dffffc0000000000 RSI: ffffffff8a8b3da0 RDI: ffffffff8ad904c0
RBP: ffffc90002e97690 R08: dffffc0000000000 R09: fffffbfff20e2419
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff920005d2eb0
R13: dffffc0000000000 R14: ffffc90002e975a0 R15: 0000000000000246
 rcu_lock_acquire+0x20/0x30 include/linux/rcupdate.h:312
 rcu_read_lock include/linux/rcupdate.h:739 [inline]
 get_mem_cgroup_from_mm+0x31/0x260 mm/memcontrol.c:986
 __mem_cgroup_charge+0x12/0x80 mm/memcontrol.c:6797
 mem_cgroup_charge include/linux/memcontrol.h:700 [inline]
 shmem_add_to_page_cache+0xc22/0x17c0 mm/shmem.c:718
 shmem_getpage_gfp+0x1aa1/0x3190 mm/shmem.c:1940
 shmem_getpage mm/shmem.c:151 [inline]
 shmem_write_begin+0xce/0x1a0 mm/shmem.c:2477
 generic_perform_write+0x2bf/0x5b0 mm/filemap.c:3785
 __generic_file_write_iter+0x243/0x4f0 mm/filemap.c:3912
 generic_file_write_iter+0xa7/0x1b0 mm/filemap.c:3944
 call_write_iter include/linux/fs.h:2172 [inline]
 new_sync_write fs/read_write.c:507 [inline]
 vfs_write+0xacd/0xe50 fs/read_write.c:594
 ksys_write+0x1a2/0x2c0 fs/read_write.c:647
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f1266dbcff9
RSP: 002b:00007f1265235038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f1266f74f80 RCX: 00007f1266dbcff9
RDX: 000000000208e24b RSI: 0000000020000240 RDI: 0000000000000005
RBP: 00007f1266e2f296 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f1266f74f80 R15: 00007ffff47a2bc8
 </TASK>
rcu: rcu_preempt kthread starved for 9800 jiffies! g21317 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
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:R  running task     stack:26816 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5027 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6373
 schedule+0x11b/0x1f0 kernel/sched/core.c:6456
 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1914
 rcu_gp_fqs_loop+0x2bf/0x1080 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0xa4/0x360 kernel/rcu/tree.c:2145
 kthread+0x3f6/0x4f0 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 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
NMI backtrace for cpu 1 skipped: idling at acpi_safe_halt drivers/acpi/processor_idle.c:108 [inline]
NMI backtrace for cpu 1 skipped: idling at acpi_idle_do_entry+0x10f/0x340 drivers/acpi/processor_idle.c:562