RBP: 000000000072bea0 R08: 0000000020000300 R09: 0000000000000000
R10: 0000000020000180 R11: 0000000000000246 R12: 0000000000000018
R13: 0000000000000051 R14: 00000000006f2838 R15: 0000000000000002
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: 0 Comm: swapper/0 Not tainted 4.16.0-rc7+ #5
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__delayacct_blkio_end+0x4b/0xb0 kernel/delayacct.c:82
RSP: 0018:ffff8801db206ac8 EFLAGS: 00010002
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff8173aa71
RDX: 0000000000000007 RSI: 0000000000000004 RDI: 0000000000000038
RBP: ffff8801db206ae0 R08: 1ffff1003b640c9b R09: ffff8801bd5425e4
R10: 0000000000000000 R11: ffff8801db206b70 R12: ffff8801db206cb0
R13: ffff8801bd542d38 R14: ffff8801bd542580 R15: ffff8801bd542a0c
FS:  0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000072c000 CR3: 0000000007a22003 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 delayacct_blkio_end include/linux/delayacct.h:128 [inline]
 try_to_wake_up+0xb7d/0x15f0 kernel/sched/core.c:2060
 default_wake_function+0x30/0x50 kernel/sched/core.c:3693
 autoremove_wake_function+0x78/0x350 kernel/sched/wait.c:377
 wake_bit_function+0xbc/0x140 kernel/sched/wait_bit.c:33
 __wake_up_common+0x18e/0x780 kernel/sched/wait.c:97
 __wake_up_common_lock+0x1b4/0x310 kernel/sched/wait.c:125
 __wake_up+0xe/0x10 kernel/sched/wait.c:149
 __wake_up_bit+0x1a4/0x2a0 kernel/sched/wait_bit.c:124
 wake_up_bit+0x3d/0x40 kernel/sched/wait_bit.c:147
 journal_end_buffer_io_sync+0x82/0xc0 fs/jbd2/commit.c:44
 end_bio_bh_io_sync+0xc5/0x110 fs/buffer.c:2992
 bio_endio+0x447/0x950 block/bio.c:1775
 req_bio_endio block/blk-core.c:208 [inline]
 blk_update_request+0x265/0xda0 block/blk-core.c:2990
 scsi_end_request+0xc8/0x820 drivers/scsi/scsi_lib.c:660
 scsi_io_completion+0x8ab/0x16b0 drivers/scsi/scsi_lib.c:868
 scsi_finish_command+0x5f6/0x890 drivers/scsi/scsi.c:248
 scsi_softirq_done+0x3ab/0x480 drivers/scsi/scsi_lib.c:1653
 __blk_mq_complete_request+0x564/0x990 block/blk-mq.c:559
 blk_mq_complete_request+0x1f6/0x320 block/blk-mq.c:644
 scsi_mq_done+0xd6/0x3c0 drivers/scsi/scsi_lib.c:1964
 virtscsi_complete_cmd+0x489/0x6f0 drivers/scsi/virtio_scsi.c:207
 virtscsi_vq_done+0xc1/0x150 drivers/scsi/virtio_scsi.c:223
 virtscsi_req_done+0xa7/0xd0 drivers/scsi/virtio_scsi.c:238
 vring_interrupt+0x109/0x150 drivers/virtio/virtio_ring.c:951
 __handle_irq_event_percpu+0x1ad/0x9d0 kernel/irq/handle.c:147
 handle_irq_event_percpu+0x98/0x1b0 kernel/irq/handle.c:187
 handle_irq_event+0xa7/0x140 kernel/irq/handle.c:204
 handle_edge_irq+0x1d5/0x7c0 kernel/irq/chip.c:793
 generic_handle_irq_desc include/linux/irqdesc.h:159 [inline]
 handle_irq+0x17a/0x300 arch/x86/kernel/irq_64.c:77
 do_IRQ+0x78/0x190 arch/x86/kernel/irq.c:238
 common_interrupt+0xf/0xf arch/x86/entry/entry_64.S:636
 </IRQ>
RIP: 0010:native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:54
RSP: 0018:ffffffff87a07c38 EFLAGS: 00000282 ORIG_RAX: ffffffffffffffda
RAX: dffffc0000000000 RBX: 1ffffffff0f40f8a RCX: 0000000000000000
RDX: 1ffffffff0f59580 RSI: 0000000000000001 RDI: ffffffff87acac00
RBP: ffffffff87a07c38 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffffffff87a07cf0 R14: ffffffff883b4820 R15: 0000000000000000
 arch_safe_halt arch/x86/include/asm/paravirt.h:94 [inline]
 default_idle+0xbf/0x430 arch/x86/kernel/process.c:354
 arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:345
 default_idle_call+0x36/0x90 kernel/sched/idle.c:98
 cpuidle_idle_call kernel/sched/idle.c:156 [inline]
 do_idle+0x24a/0x3b0 kernel/sched/idle.c:246
 cpu_startup_entry+0x104/0x120 kernel/sched/idle.c:351
 rest_init+0xed/0xf0 init/main.c:437
 start_kernel+0x7f1/0x819 init/main.c:717
 x86_64_start_reservations+0x2a/0x2c arch/x86/kernel/head64.c:378
 x86_64_start_kernel+0x77/0x7a arch/x86/kernel/head64.c:359
 secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:239
Code: ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 6f 48 8b 9b 70 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 40 f6 43 38 01 75 2b 4c 8d 63 
RIP: __delayacct_blkio_end+0x4b/0xb0 kernel/delayacct.c:82 RSP: ffff8801db206ac8

======================================================
WARNING: possible circular locking dependency detected
4.16.0-rc7+ #5 Not tainted
------------------------------------------------------
swapper/0/0 is trying to acquire lock:
 ((console_sem).lock){-...}, at: [<000000002b9ce924>] down_trylock+0x13/0x70 kernel/locking/semaphore.c:136

but task is already holding lock:
 (&p->pi_lock){-.-.}, at: [<00000000b2df2a41>] try_to_wake_up+0xbc/0x15f0 kernel/sched/core.c:1989

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+0xbc/0x15f0 kernel/sched/core.c:1989
       wake_up_process+0x10/0x20 kernel/sched/core.c:2152
       __up.isra.0+0x1cc/0x2c0 kernel/locking/semaphore.c:262
       up+0x13b/0x1d0 kernel/locking/semaphore.c:187
       __up_console_sem+0xb2/0x1a0 kernel/printk/printk.c:242
       console_unlock+0x5af/0xfb0 kernel/printk/printk.c:2417
       do_con_write+0x106e/0x1f70 drivers/tty/vt/vt.c:2433
       con_write+0x25/0xb0 drivers/tty/vt/vt.c:2782
       process_output_block drivers/tty/n_tty.c:579 [inline]
       n_tty_write+0x5ef/0xec0 drivers/tty/n_tty.c:2308
       do_tty_write drivers/tty/tty_io.c:958 [inline]
       tty_write+0x3fa/0x840 drivers/tty/tty_io.c:1042
       __vfs_write+0xef/0x970 fs/read_write.c:480
       vfs_write+0x189/0x510 fs/read_write.c:544
       SYSC_write fs/read_write.c:589 [inline]
       SyS_write+0xef/0x220 fs/read_write.c:581
       do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287
       entry_SYSCALL_64_after_hwframe+0x42/0xb7

-> #0 ((console_sem).lock){-...}:
       lock_acquire+0x1d5/0x580 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+0xa2/0x1e0 kernel/printk/printk.c:225
       console_trylock+0x15/0x70 kernel/printk/printk.c:2229
       console_trylock_spinning kernel/printk/printk.c:1643 [inline]
       vprintk_emit+0x5b5/0xb90 kernel/printk/printk.c:1906
       vprintk_default+0x28/0x30 kernel/printk/printk.c:1947
       vprintk_func+0x57/0xc0 kernel/printk/printk_safe.c:379
       printk+0xaa/0xca kernel/printk/printk.c:1980
       kasan_die_handler+0x31/0x3f arch/x86/mm/kasan_init_64.c:247
       notifier_call_chain+0x136/0x2c0 kernel/notifier.c:93
       __atomic_notifier_call_chain kernel/notifier.c:183 [inline]
       atomic_notifier_call_chain+0x77/0x140 kernel/notifier.c:193
       notify_die+0x18c/0x280 kernel/notifier.c:549
       do_general_protection+0x331/0x3e0 arch/x86/kernel/traps.c:558
       general_protection+0x25/0x50 arch/x86/entry/entry_64.S:1150
       __delayacct_blkio_end+0x4b/0xb0 kernel/delayacct.c:82
       delayacct_blkio_end include/linux/delayacct.h:128 [inline]
       try_to_wake_up+0xb7d/0x15f0 kernel/sched/core.c:2060
       default_wake_function+0x30/0x50 kernel/sched/core.c:3693
       autoremove_wake_function+0x78/0x350 kernel/sched/wait.c:377
       wake_bit_function+0xbc/0x140 kernel/sched/wait_bit.c:33
       __wake_up_common+0x18e/0x780 kernel/sched/wait.c:97
       __wake_up_common_lock+0x1b4/0x310 kernel/sched/wait.c:125
       __wake_up+0xe/0x10 kernel/sched/wait.c:149
       __wake_up_bit+0x1a4/0x2a0 kernel/sched/wait_bit.c:124
       wake_up_bit+0x3d/0x40 kernel/sched/wait_bit.c:147
       journal_end_buffer_io_sync+0x82/0xc0 fs/jbd2/commit.c:44
       end_bio_bh_io_sync+0xc5/0x110 fs/buffer.c:2992
       bio_endio+0x447/0x950 block/bio.c:1775
       req_bio_endio block/blk-core.c:208 [inline]
       blk_update_request+0x265/0xda0 block/blk-core.c:2990
       scsi_end_request+0xc8/0x820 drivers/scsi/scsi_lib.c:660
       scsi_io_completion+0x8ab/0x16b0 drivers/scsi/scsi_lib.c:868
       scsi_finish_command+0x5f6/0x890 drivers/scsi/scsi.c:248
       scsi_softirq_done+0x3ab/0x480 drivers/scsi/scsi_lib.c:1653
       __blk_mq_complete_request+0x564/0x990 block/blk-mq.c:559
       blk_mq_complete_request+0x1f6/0x320 block/blk-mq.c:644
       scsi_mq_done+0xd6/0x3c0 drivers/scsi/scsi_lib.c:1964
       virtscsi_complete_cmd+0x489/0x6f0 drivers/scsi/virtio_scsi.c:207
       virtscsi_vq_done+0xc1/0x150 drivers/scsi/virtio_scsi.c:223
       virtscsi_req_done+0xa7/0xd0 drivers/scsi/virtio_scsi.c:238
       vring_interrupt+0x109/0x150 drivers/virtio/virtio_ring.c:951
       __handle_irq_event_percpu+0x1ad/0x9d0 kernel/irq/handle.c:147
       handle_irq_event_percpu+0x98/0x1b0 kernel/irq/handle.c:187
       handle_irq_event+0xa7/0x140 kernel/irq/handle.c:204
       handle_edge_irq+0x1d5/0x7c0 kernel/irq/chip.c:793
       generic_handle_irq_desc include/linux/irqdesc.h:159 [inline]
       handle_irq+0x17a/0x300 arch/x86/kernel/irq_64.c:77
       do_IRQ+0x78/0x190 arch/x86/kernel/irq.c:238
       ret_from_intr+0x0/0x1e
       native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:54
       arch_safe_halt arch/x86/include/asm/paravirt.h:94 [inline]
       default_idle+0xbf/0x430 arch/x86/kernel/process.c:354
       arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:345
       default_idle_call+0x36/0x90 kernel/sched/idle.c:98
       cpuidle_idle_call kernel/sched/idle.c:156 [inline]
       do_idle+0x24a/0x3b0 kernel/sched/idle.c:246
       cpu_startup_entry+0x104/0x120 kernel/sched/idle.c:351
       rest_init+0xed/0xf0 init/main.c:437
       start_kernel+0x7f1/0x819 init/main.c:717
       x86_64_start_reservations+0x2a/0x2c arch/x86/kernel/head64.c:378
       x86_64_start_kernel+0x77/0x7a arch/x86/kernel/head64.c:359
       secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:239

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 ***

5 locks held by swapper/0/0:
 #0:  (&(&virtscsi_vq->vq_lock)->rlock){-.-.}, at: [<000000005b7284ab>] virtscsi_vq_done+0x9d/0x150 drivers/scsi/virtio_scsi.c:219
 #1:  (rcu_read_lock){....}, at: [<00000000f512e426>] hctx_lock+0xd8/0x190 block/blk-mq.c:578
 #2:  (bit_wait_table + i){-.-.}, at: [<000000003551c654>] __wake_up_common_lock+0x190/0x310 kernel/sched/wait.c:124
 #3:  (&p->pi_lock){-.-.}, at: [<00000000b2df2a41>] try_to_wake_up+0xbc/0x15f0 kernel/sched/core.c:1989
 #4:  (rcu_read_lock){....}, at: [<00000000ac010327>] rcu_read_unlock include/linux/rcupdate.h:682 [inline]
 #4:  (rcu_read_lock){....}, at: [<00000000ac010327>] atomic_notifier_call_chain+0x0/0x140 kernel/notifier.c:184

stack backtrace:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.16.0-rc7+ #5
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x194/0x24d lib/dump_stack.c:53
 print_circular_bug.isra.38+0x2cd/0x2dc 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+0x30a8/0x3e00 kernel/locking/lockdep.c:3431
 lock_acquire+0x1d5/0x580 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+0xa2/0x1e0 kernel/printk/printk.c:225
 console_trylock+0x15/0x70 kernel/printk/printk.c:2229
 console_trylock_spinning kernel/printk/printk.c:1643 [inline]
 vprintk_emit+0x5b5/0xb90 kernel/printk/printk.c:1906
 vprintk_default+0x28/0x30 kernel/printk/printk.c:1947
 vprintk_func+0x57/0xc0 kernel/printk/printk_safe.c:379
 printk+0xaa/0xca kernel/printk/printk.c:1980
 kasan_die_handler+0x31/0x3f arch/x86/mm/kasan_init_64.c:247
 notifier_call_chain+0x136/0x2c0 kernel/notifier.c:93
 __atomic_notifier_call_chain kernel/notifier.c:183 [inline]
 atomic_notifier_call_chain+0x77/0x140 kernel/notifier.c:193
 notify_die+0x18c/0x280 kernel/notifier.c:549
 do_general_protection+0x331/0x3e0 arch/x86/kernel/traps.c:558
 general_protection+0x25/0x50 arch/x86/entry/entry_64.S:1150
RIP: 0010:__delayacct_blkio_end+0x4b/0xb0 kernel/delayacct.c:82
RSP: 0018:ffff8801db206ac8 EFLAGS: 00010002
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff8173aa71
RDX: 0000000000000007 RSI: 0000000000000004 RDI: 0000000000000038
RBP: ffff8801db206ae0 R08: 1ffff1003b640c9b R09: ffff8801bd5425e4
R10: 0000000000000000 R11: ffff8801db206b70 R12: ffff8801db206cb0
R13: ffff8801bd542d38 R14: ffff8801bd542580 R15: ffff8801bd542a0c
 delayacct_blkio_end include/linux/delayacct.h:128 [inline]
 try_to_wake_up+0xb7d/0x15f0 kernel/sched/core.c:2060
 default_wake_function+0x30/0x50 kernel/sched/core.c:3693
 autoremove_wake_function+0x78/0x350 kernel/sched/wait.c:377
 wake_bit_function+0xbc/0x140 kernel/sched/wait_bit.c:33
 __wake_up_common+0x18e/0x780 kernel/sched/wait.c:97
 __wake_up_common_lock+0x1b4/0x310 kernel/sched/wait.c:125
 __wake_up+0xe/0x10 kernel/sched/wait.c:149
 __wake_up_bit+0x1a4/0x2a0 kernel/sched/wait_bit.c:124
 wake_up_bit+0x3d/0x40 kernel/sched/wait_bit.c:147
 journal_end_buffer_io_sync+0x82/0xc0 fs/jbd2/commit.c:44
 end_bio_bh_io_sync+0xc5/0x110 fs/buffer.c:2992
 bio_endio+0x447/0x950 block/bio.c:1775
 ? bio_di
Lost 102 message(s)!
---[ end trace c1196def7dfb53aa ]---