IPVS: ftp: loaded support on port[0] = 21
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 1510 Comm: kswapd0 Not tainted 4.17.0-rc1+ #13
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__delayacct_blkio_end+0x4f/0xc0 kernel/delayacct.c:82
RSP: 0018:ffff8801dae06970 EFLAGS: 00010002
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffff880194b624b8
RDX: 0000000000000007 RSI: ffffffff817a3be1 RDI: 0000000000000038
RBP: ffff8801dae06988 R08: ffffed003b5c46c3 R09: 0000000000000001
R10: ffff8801dae06a18 R11: ffff8801dae23613 R12: ffff8801d3dda5c0
R13: ffff880194b62480 R14: ffff880194b624bc R15: 0000000000000002
FS:  0000000000000000(0000) GS:ffff8801dae00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4644630000 CR3: 00000001b0a08000 CR4: 00000000001406f0
DR0: 0000000020000000 DR1: 0000000020000000 DR2: 0000000020000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 delayacct_blkio_end include/linux/delayacct.h:128 [inline]
 try_to_wake_up+0xa89/0x1190 kernel/sched/core.c:2034
 default_wake_function+0x30/0x50 kernel/sched/core.c:3743
 autoremove_wake_function+0x7a/0x350 kernel/sched/wait.c:373
 wake_page_function+0x15f/0x1c0 mm/filemap.c:1010
 __wake_up_common+0x189/0x730 kernel/sched/wait.c:90
 __wake_up_locked_key_bookmark+0x16/0x20 kernel/sched/wait.c:165
 wake_up_page_bit+0x297/0x580 mm/filemap.c:1030
 unlock_page+0x214/0x2b0 mm/filemap.c:1207
 mpage_end_io+0x228/0x4c0 fs/ext4/readpage.c:93
 bio_endio+0x4b8/0x920 block/bio.c:1775
 req_bio_endio block/blk-core.c:280 [inline]
 blk_update_request+0x3a3/0xcb0 block/blk-core.c:3099
 scsi_end_request+0xd3/0x870 drivers/scsi/scsi_lib.c:672
 scsi_io_completion+0xca9/0x1d10 drivers/scsi/scsi_lib.c:898
 scsi_finish_command+0x542/0x8d0 drivers/scsi/scsi.c:248
 scsi_softirq_done+0x3d9/0x4b0 drivers/scsi/scsi_lib.c:1683
 __blk_mq_complete_request+0x4c8/0x9f0 block/blk-mq.c:551
 blk_mq_complete_request+0x2a5/0x370 block/blk-mq.c:636
 scsi_mq_done+0xe2/0x430 drivers/scsi/scsi_lib.c:1994
 virtscsi_complete_cmd+0x573/0x740 drivers/scsi/virtio_scsi.c:207
 virtscsi_vq_done+0xc3/0x170 drivers/scsi/virtio_scsi.c:223
 virtscsi_req_done+0xa7/0xd0 drivers/scsi/virtio_scsi.c:238
 vring_interrupt+0x128/0x170 drivers/virtio/virtio_ring.c:950
 __handle_irq_event_percpu+0x1c0/0xad0 kernel/irq/handle.c:149
 handle_irq_event_percpu+0x98/0x1c0 kernel/irq/handle.c:189
 handle_irq_event+0xa7/0x135 kernel/irq/handle.c:206
 handle_edge_irq+0x20f/0x870 kernel/irq/chip.c:791
 generic_handle_irq_desc include/linux/irqdesc.h:159 [inline]
 handle_irq+0x18c/0x2e7 arch/x86/kernel/irq_64.c:77
 do_IRQ+0x78/0x190 arch/x86/kernel/irq.c:245
 common_interrupt+0xf/0xf arch/x86/entry/entry_64.S:642
 </IRQ>
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:783 [inline]
RIP: 0010:lock_release+0x4d4/0xa10 kernel/locking/lockdep.c:3942
RSP: 0018:ffff8801d3d87228 EFLAGS: 00000286 ORIG_RAX: ffffffffffffffda
RAX: dffffc0000000000 RBX: 1ffff1003a7b0e4a RCX: 1ffff1003a7bb5bd
RDX: 1ffffffff11a312d RSI: 0000000000000002 RDI: 0000000000000286
RBP: ffff8801d3d87358 R08: 1ffff1003a7b0e4e R09: ffff8801d3d870b0
R10: 0000000000000003 R11: 0000000000000001 R12: ffff8801d3dda5c0
R13: ffffffff88d8e4e0 R14: ffff8801d3dda5c0 R15: ffff8801d3d87270
 rcu_lock_release include/linux/rcupdate.h:251 [inline]
 rcu_read_unlock include/linux/rcupdate.h:688 [inline]
 __list_lru_count_one mm/list_lru.c:175 [inline]
 list_lru_count_one+0x27f/0x440 mm/list_lru.c:183
 list_lru_shrink_count include/linux/list_lru.h:118 [inline]
 super_cache_count+0x16b/0x280 fs/super.c:135
 do_shrink_slab mm/vmscan.c:374 [inline]
 shrink_slab.part.39+0x330/0xf90 mm/vmscan.c:531
 shrink_slab+0xa1/0xc0 mm/vmscan.c:506
 shrink_node+0x4f2/0x1740 mm/vmscan.c:2561
 kswapd_shrink_node mm/vmscan.c:3279 [inline]
 balance_pgdat+0x73e/0xf30 mm/vmscan.c:3385
 kswapd+0x825/0x12e0 mm/vmscan.c:3604
 kthread+0x345/0x410 kernel/kthread.c:238
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412
Code: fa 48 c1 ea 03 80 3c 02 00 0f 85 80 00 00 00 48 8b 9b 30 12 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d 7b 38 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 04 3c 03 7e 51 44 8b 63 38 31 ff 41 83 e4 
RIP: __delayacct_blkio_end+0x4f/0xc0 kernel/delayacct.c:82 RSP: ffff8801dae06970

======================================================
WARNING: possible circular locking dependency detected
4.17.0-rc1+ #13 Not tainted
------------------------------------------------------
kswapd0/1510 is trying to acquire lock:
000000007b573fe2 ((console_sem).lock){-...}, at: down_trylock+0x13/0x70 kernel/locking/semaphore.c:136

but task is already holding lock:
00000000c437595b (&p->pi_lock){-.-.}, at: try_to_wake_up+0xca/0x1190 kernel/sched/core.c:1963

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&p->pi_lock){-.-.}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x96/0xc0 kernel/locking/spinlock.c:152
       try_to_wake_up+0xca/0x1190 kernel/sched/core.c:1963
       wake_up_process+0x10/0x20 kernel/sched/core.c:2126
       __up.isra.1+0x1b8/0x290 kernel/locking/semaphore.c:262
       up+0x12f/0x1b0 kernel/locking/semaphore.c:187
       __up_console_sem+0xbe/0x1b0 kernel/printk/printk.c:242
       console_unlock+0x7d6/0x1100 kernel/printk/printk.c:2417
       do_con_write+0x12b2/0x2280 drivers/tty/vt/vt.c:2437
       con_write+0x25/0xc0 drivers/tty/vt/vt.c:2786
       process_output_block drivers/tty/n_tty.c:579 [inline]
       n_tty_write+0x6b9/0x1180 drivers/tty/n_tty.c:2308
       do_tty_write drivers/tty/tty_io.c:958 [inline]
       tty_write+0x3f1/0x880 drivers/tty/tty_io.c:1042
       __vfs_write+0x10b/0x960 fs/read_write.c:485
       vfs_write+0x1f8/0x560 fs/read_write.c:549
       ksys_write+0xf9/0x250 fs/read_write.c:598
       __do_sys_write fs/read_write.c:610 [inline]
       __se_sys_write fs/read_write.c:607 [inline]
       __x64_sys_write+0x73/0xb0 fs/read_write.c:607
       do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
       entry_SYSCALL_64_after_hwframe+0x49/0xbe

-> #0 ((console_sem).lock){-...}:
       lock_acquire+0x1dc/0x520 kernel/locking/lockdep.c:3920
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x96/0xc0 kernel/locking/spinlock.c:152
       down_trylock+0x13/0x70 kernel/locking/semaphore.c:136
       __down_trylock_console_sem+0xae/0x200 kernel/printk/printk.c:225
       console_trylock+0x15/0xa0 kernel/printk/printk.c:2229
       console_trylock_spinning kernel/printk/printk.c:1643 [inline]
       vprintk_emit+0x694/0xdd0 kernel/printk/printk.c:1906
       vprintk_default+0x28/0x30 kernel/printk/printk.c:1947
       vprintk_func+0x7a/0xe7 kernel/printk/printk_safe.c:379
       printk+0x9e/0xba kernel/printk/printk.c:1980
       kasan_die_handler.cold.22+0x11/0x30 arch/x86/mm/kasan_init_64.c:253
       notifier_call_chain+0x178/0x380 kernel/notifier.c:93
       __atomic_notifier_call_chain kernel/notifier.c:183 [inline]
       atomic_notifier_call_chain+0x98/0x190 kernel/notifier.c:193
       notify_die+0x1a3/0x2b0 kernel/notifier.c:549
       do_general_protection+0x248/0x2f0 arch/x86/kernel/traps.c:558
       general_protection+0x1e/0x30 arch/x86/entry/entry_64.S:1159
       __delayacct_blkio_end+0x4f/0xc0 kernel/delayacct.c:82
       delayacct_blkio_end include/linux/delayacct.h:128 [inline]
       try_to_wake_up+0xa89/0x1190 kernel/sched/core.c:2034
       default_wake_function+0x30/0x50 kernel/sched/core.c:3743
       autoremove_wake_function+0x7a/0x350 kernel/sched/wait.c:373
       wake_page_function+0x15f/0x1c0 mm/filemap.c:1010
       __wake_up_common+0x189/0x730 kernel/sched/wait.c:90
       __wake_up_locked_key_bookmark+0x16/0x20 kernel/sched/wait.c:165
       wake_up_page_bit+0x297/0x580 mm/filemap.c:1030
       unlock_page+0x214/0x2b0 mm/filemap.c:1207
       mpage_end_io+0x228/0x4c0 fs/ext4/readpage.c:93
       bio_endio+0x4b8/0x920 block/bio.c:1775
       req_bio_endio block/blk-core.c:280 [inline]
       blk_update_request+0x3a3/0xcb0 block/blk-core.c:3099
       scsi_end_request+0xd3/0x870 drivers/scsi/scsi_lib.c:672
       scsi_io_completion+0xca9/0x1d10 drivers/scsi/scsi_lib.c:898
       scsi_finish_command+0x542/0x8d0 drivers/scsi/scsi.c:248
       scsi_softirq_done+0x3d9/0x4b0 drivers/scsi/scsi_lib.c:1683
       __blk_mq_complete_request+0x4c8/0x9f0 block/blk-mq.c:551
       blk_mq_complete_request+0x2a5/0x370 block/blk-mq.c:636
       scsi_mq_done+0xe2/0x430 drivers/scsi/scsi_lib.c:1994
       virtscsi_complete_cmd+0x573/0x740 drivers/scsi/virtio_scsi.c:207
       virtscsi_vq_done+0xc3/0x170 drivers/scsi/virtio_scsi.c:223
       virtscsi_req_done+0xa7/0xd0 drivers/scsi/virtio_scsi.c:238
       vring_interrupt+0x128/0x170 drivers/virtio/virtio_ring.c:950
       __handle_irq_event_percpu+0x1c0/0xad0 kernel/irq/handle.c:149
       handle_irq_event_percpu+0x98/0x1c0 kernel/irq/handle.c:189
       handle_irq_event+0xa7/0x135 kernel/irq/handle.c:206
       handle_edge_irq+0x20f/0x870 kernel/irq/chip.c:791
       generic_handle_irq_desc include/linux/irqdesc.h:159 [inline]
       handle_irq+0x18c/0x2e7 arch/x86/kernel/irq_64.c:77
       do_IRQ+0x78/0x190 arch/x86/kernel/irq.c:245
       ret_from_intr+0x0/0x1e
       arch_local_irq_restore arch/x86/include/asm/paravirt.h:783 [inline]
       lock_release+0x4d4/0xa10 kernel/locking/lockdep.c:3942
       rcu_lock_release include/linux/rcupdate.h:251 [inline]
       rcu_read_unlock include/linux/rcupdate.h:688 [inline]
       __list_lru_count_one mm/list_lru.c:175 [inline]
       list_lru_count_one+0x27f/0x440 mm/list_lru.c:183
       list_lru_shrink_count include/linux/list_lru.h:118 [inline]
       super_cache_count+0x16b/0x280 fs/super.c:135
       do_shrink_slab mm/vmscan.c:374 [inline]
       shrink_slab.part.39+0x330/0xf90 mm/vmscan.c:531
       shrink_slab+0xa1/0xc0 mm/vmscan.c:506
       shrink_node+0x4f2/0x1740 mm/vmscan.c:2561
       kswapd_shrink_node mm/vmscan.c:3279 [inline]
       balance_pgdat+0x73e/0xf30 mm/vmscan.c:3385
       kswapd+0x825/0x12e0 mm/vmscan.c:3604
       kthread+0x345/0x410 kernel/kthread.c:238
       ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&p->pi_lock);
                               lock((console_sem).lock);
                               lock(&p->pi_lock);
  lock((console_sem).lock);

 *** DEADLOCK ***

6 locks held by kswapd0/1510:
 #0: 00000000ceabb5ee (shrinker_rwsem){++++}, at: shrink_slab.part.39+0xe6/0xf90 mm/vmscan.c:509
 #1: 000000006357fdda (&(&virtscsi_vq->vq_lock)->rlock){-.-.}, at: virtscsi_vq_done+0x9d/0x170 drivers/scsi/virtio_scsi.c:219
 #2: 00000000e8c9b75d (rcu_read_lock){....}, at: hctx_lock+0x7a/0x1d0 block/blk-mq.c:570
 #3: 000000004c76d76c (&page_wait_table[i]){-.-.}, at: wake_up_page_bit+0x27d/0x580 mm/filemap.c:1029
 #4: 00000000c437595b (&p->pi_lock){-.-.}, at: try_to_wake_up+0xca/0x1190 kernel/sched/core.c:1963
 #5: 00000000e8c9b75d (rcu_read_lock){....}, at: atomic_notifier_call_chain+0x0/0x190 include/linux/compiler.h:188

stack backtrace:
CPU: 0 PID: 1510 Comm: kswapd0 Not tainted 4.17.0-rc1+ #13
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+0x1b9/0x294 lib/dump_stack.c:113
 print_circular_bug.isra.36.cold.54+0x1bd/0x27d kernel/locking/lockdep.c:1223
 check_prev_add kernel/locking/lockdep.c:1863 [inline]
 check_prevs_add kernel/locking/lockdep.c:1976 [inline]
 validate_chain kernel/locking/lockdep.c:2417 [inline]
 __lock_acquire+0x343e/0x5140 kernel/locking/lockdep.c:3431
 lock_acquire+0x1dc/0x520 kernel/locking/lockdep.c:3920
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0x96/0xc0 kernel/locking/spinlock.c:152
 down_trylock+0x13/0x70 kernel/locking/semaphore.c:136
 __down_trylock_console_sem+0xae/0x200 kernel/printk/printk.c:225
 console_trylock+0x15/0xa0 kernel/printk/printk.c:2229
 console_trylock_spinning kernel/printk/printk.c:1643 [inline]
 vprintk_emit+0x694/0xdd0 kernel/printk/printk.c:1906
 vprintk_default+0x28/0x30 kernel/printk/printk.c:1947
 vprintk_func+0x7a/0xe7 kernel/printk/printk_safe.c:379
 printk+0x9e/0xba kernel/printk/printk.c:1980
 kasan_die_handler.cold.22+0x11/0x30 arch/x86/mm/kasan_init_64.c:253
 notifier_call_chain+0x178/0x380 kernel/notifier.c:93
 __atomic_notifier_call_chain kernel/notifier.c:183 [inline]
 atomic_notifier_call_chain+0x98/0x190 kernel/notifier.c:193
 notify_die+0x1a3/0x2b0 kernel/notifier.c:549
 do_general_protection+0x248/0x2f0 arch/x86/kernel/traps.c:558
 general_protection+0x1e/0x30 arch/x86/entry/entry_64.S:1159
RIP: 0010:__delayacct_blkio_end+0x4f/0xc0 kernel/delayacct.c:82
RSP: 0018:ffff8801dae06970 EFLAGS: 00010002
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffff880194b624b8
RDX: 0000000000000007 RSI: ffffffff817a3be1 RDI: 0000000000000038
RBP: ffff8801dae06988 R08: ffffed003b5c46c3 R09: 0000000000000001
R10: ffff8801dae06a18 R11: ffff8801dae23613 R12: ffff8801d3dda5c0
R13: ffff880194b62480 R14: ffff880194b624bc R15: 0000000000000002
 delayacct_blkio_end include/linux/delayacct.h:128 [inline]
 try_to_wake_up+0xa89/0x1190 kernel/sched/core.c:2034
 default_wake_function+0x30/0x50 kernel/sched/core.c:3743
 autoremove_wake_function+0x7a/0x350 kernel/sched/wait.c:373
 wake_page_function+0x15f/0x1c0 mm/filemap.c:1010
 __wake_up_common+0x189/0x730 kernel/sched/wait.c:90
 __wake_up_locked_key_bookmark+0x16/0x20 kernel/sched/wait.c:165
 wake_up_page_bit+0x297/0x580 mm/filemap.c:1030
 unlock_page+0x214/0x2b0 mm/filemap.c:1207
 mpage_end_io+0x228/0x4c0 fs/ext4/readpage.c:93
 bio_endio+0x4b8/0x920 block/bio.c:1775
Lost 121 message(s)!
---[ end trace 4c6395a3142cb78e ]---