syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5318/1:b..l
	(detected by 1, t=10502 jiffies, g=67145, q=248)
task:syz.0.452       state:R  running task     stack:19896 pid: 5318 ppid:  4610 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6376
 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6780
 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 cc 86 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:ffffc90002eb65a0 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 1ffff920005d6cc0 RCX: 1ffff920005d6c60
RDX: dffffc0000000000 RSI: ffffffff8a8b3ca0 RDI: ffffffff8ad8f800
RBP: ffffc90002eb66e8 R08: dffffc0000000000 R09: fffffbfff1f8e019
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff920005d6cbc
R13: dffffc0000000000 R14: ffffc90002eb6600 R15: 0000000000000246
 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:312
 rcu_read_lock include/linux/rcupdate.h:739 [inline]
 next_demotion_node+0x13/0x190 mm/migrate.c:1177
 demote_page_list mm/vmscan.c:1338 [inline]
 shrink_page_list+0x6428/0x7540 mm/vmscan.c:1798
 shrink_inactive_list mm/vmscan.c:2216 [inline]
 shrink_list mm/vmscan.c:2443 [inline]
 shrink_lruvec+0x14ae/0x2b90 mm/vmscan.c:2762
 shrink_node_memcgs mm/vmscan.c:2949 [inline]
 shrink_node+0x10b3/0x26d0 mm/vmscan.c:3072
 shrink_zones mm/vmscan.c:3278 [inline]
 do_try_to_free_pages+0x697/0x17b0 mm/vmscan.c:3333
 try_to_free_mem_cgroup_pages+0x44c/0xa60 mm/vmscan.c:3647
 try_charge_memcg+0x4f4/0x1530 mm/memcontrol.c:2651
 try_charge mm/memcontrol.c:2776 [inline]
 charge_memcg+0x10b/0x340 mm/memcontrol.c:6742
 __mem_cgroup_charge+0x23/0x80 mm/memcontrol.c:6778
 mem_cgroup_charge include/linux/memcontrol.h:700 [inline]
 __add_to_page_cache_locked+0xbdb/0x11a0 mm/filemap.c:892
 add_to_page_cache_lru+0x1b3/0x560 mm/filemap.c:984
 do_read_cache_page+0x205/0x1040 mm/filemap.c:3460
 read_mapping_page include/linux/pagemap.h:515 [inline]
 dir_get_page fs/sysv/dir.c:58 [inline]
 sysv_find_entry+0x1b0/0x650 fs/sysv/dir.c:146
 sysv_inode_by_name+0x9e/0x3f0 fs/sysv/dir.c:360
 sysv_lookup+0x63/0xe0 fs/sysv/namei.c:38
 lookup_one_qstr_excl+0x117/0x240 fs/namei.c:1563
 filename_create+0x293/0x530 fs/namei.c:3836
 kern_path_create+0x35/0x180 fs/namei.c:3876
 unix_bind_bsd net/unix/af_unix.c:1073 [inline]
 unix_bind+0x3b9/0x920 net/unix/af_unix.c:1171
 __sys_bind+0x388/0x400 net/socket.c:1715
 __do_sys_bind net/socket.c:1726 [inline]
 __se_sys_bind net/socket.c:1724 [inline]
 __x64_sys_bind+0x76/0x80 net/socket.c:1724
 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: 0033:0x7f58a4ff93b9
RSP: 002b:00007f58a3478048 EFLAGS: 00000246 ORIG_RAX: 0000000000000031
RAX: ffffffffffffffda RBX: 00007f58a5187f80 RCX: 00007f58a4ff93b9
RDX: 000000000000006e RSI: 0000000020003000 RDI: 0000000000000004
RBP: 00007f58a50668e6 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f58a5187f80 R15: 00007ffd94919fb8
 </TASK>
rcu: rcu_preempt kthread starved for 9514 jiffies! g67145 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
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:27064 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6376
 schedule+0x11b/0x1f0 kernel/sched/core.c:6459
 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 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
NMI backtrace for cpu 0 skipped: idling at acpi_safe_halt drivers/acpi/processor_idle.c:108 [inline]
NMI backtrace for cpu 0 skipped: idling at acpi_idle_do_entry+0x10f/0x340 drivers/acpi/processor_idle.c:562