syzbot has found a reproducer for the following crash on:

HEAD commit:    4c5e8fc62d6a Merge tag 'linux-kselftest-4.18-rc1-2' of git..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15fa558f800000
kernel config:  https://syzkaller.appspot.com/x/.config?x=caf58998a7a0564
dashboard link: https://syzkaller.appspot.com/bug?extid=aea12292cfdadf454c38
compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=14ee4aff800000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=108628c0400000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: [email protected]

name failslab, interval 1, probability 0, space 0, times 0
kasan: CONFIG_KASAN_INLINE enabled
CPU: 1 PID: 4798 Comm: syz-executor422 Not tainted 4.17.0+ #104
kasan: GPF could be caused by NULL-ptr deref or user memory access
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
general protection fault: 0000 [#1] SMP KASAN
Call Trace:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.17.0+ #104
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__delayacct_blkio_end+0x4f/0xc0 kernel/delayacct.c:83
Code: 48
c1
ea 03
80
3c
 fail_dump lib/fault-inject.c:51 [inline]
 should_fail.cold.4+0xa/0x1a lib/fault-inject.c:149
02
00
0f
85 80
00
00
00
48
 __should_failslab+0x124/0x180 mm/failslab.c:32
8b
 should_failslab+0x9/0x14 mm/slab_common.c:1553
9b
 slab_pre_alloc_hook mm/slab.h:423 [inline]
 slab_alloc mm/slab.c:3378 [inline]
 kmem_cache_alloc+0x2af/0x760 mm/slab.c:3552
48
12
 kmem_cache_zalloc include/linux/slab.h:697 [inline]
 __delayacct_tsk_init+0x20/0x80 kernel/delayacct.c:45
00
 delayacct_tsk_init include/linux/delayacct.h:105 [inline]
 copy_process.part.39+0x2ba8/0x7250 kernel/fork.c:1687
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 01
RSP: 0000:ffff8801dae06c28 EFLAGS: 00010002
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffff8801d9778538
RDX: 0000000000000007 RSI: ffffffff817cba01 RDI: 0000000000000038
RBP: ffff8801dae06c40 R08: ffffed003b5c46d7 R09: 0000000000000000
R10: ffff8801dae06d50 R11: ffff8801dae236b3 R12: ffffffff88e75dc0
R13: ffff8801d9778500 R14: ffff8801d977853c R15: 0000000000000002
FS:  0000000000000000(0000) GS:ffff8801dae00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000008e6a000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 copy_process kernel/fork.c:1616 [inline]
 _do_fork+0x291/0x12a0 kernel/fork.c:2099
 <IRQ>
 delayacct_blkio_end include/linux/delayacct.h:128 [inline]
 try_to_wake_up+0xacb/0x12b0 kernel/sched/core.c:2057
 default_wake_function+0x30/0x50 kernel/sched/core.c:3742
 __do_sys_clone kernel/fork.c:2206 [inline]
 __se_sys_clone kernel/fork.c:2200 [inline]
 __x64_sys_clone+0xbf/0x150 kernel/fork.c:2200
 autoremove_wake_function+0x80/0x370 kernel/sched/wait.c:373
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 wake_bit_function+0xcb/0x160 kernel/sched/wait_bit.c:30
 __wake_up_common+0x191/0x740 kernel/sched/wait.c:90
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x441519
Code:
e8
ac
b5
02
00
 __wake_up_common_lock+0x1c2/0x330 kernel/sched/wait.c:119
48
83
c4
18
c3
 __wake_up+0xe/0x10 kernel/sched/wait.c:143
0f
 __wake_up_bit+0x1af/0x290 kernel/sched/wait_bit.c:125
1f
80
00
00
00
00
48
89
 wake_up_bit+0x3d/0x40 kernel/sched/wait_bit.c:148
f8
 journal_end_buffer_io_sync+0xa4/0xe0 fs/jbd2/commit.c:44
48
 end_bio_bh_io_sync+0xf3/0x140 fs/buffer.c:2969
89
f7
 bio_endio+0x530/0x9e0 block/bio.c:1836
48
89
d6
48
89
ca
4d
89
 req_bio_endio block/blk-core.c:281 [inline]
 blk_update_request+0x3b2/0xcd0 block/blk-core.c:3091
c2
4d
89
c8
 scsi_end_request+0xde/0x890 drivers/scsi/scsi_lib.c:672
4c
8b
 scsi_io_completion+0xcc6/0x1dd0 drivers/scsi/scsi_lib.c:898
4c
24
08
0f
 scsi_finish_command+0x54a/0x8f0 drivers/scsi/scsi.c:248
05
<48>
3d
01
f0
ff
ff
0f
83
1b
09
 scsi_softirq_done+0x3f6/0x4d0 drivers/scsi/scsi_lib.c:1687
fc
ff
c3
66
 __blk_mq_complete_request block/blk-mq.c:583 [inline]
 blk_mq_complete_request+0x355/0x630 block/blk-mq.c:620
2e
 scsi_mq_done+0xe7/0x450 drivers/scsi/scsi_lib.c:1998
0f
1f
84
00
00
 virtscsi_complete_cmd+0x573/0x740 drivers/scsi/virtio_scsi.c:207
00
00
 virtscsi_vq_done+0xcb/0x180 drivers/scsi/virtio_scsi.c:223
RSP: 002b:00007ffc2ba79078 EFLAGS: 00000246
 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441519
RDX: 0000000020000440 RSI: 0000000020000340 RDI: 0000000000000000
RBP: 00007ffc2ba79090 R08: 00000000200004c0 R09: 0000000000000001
 virtscsi_req_done+0xa7/0xd0 drivers/scsi/virtio_scsi.c:238
R10: 0000000020000480 R11: 0000000000000246 R12: ffffffffffffffff
R13: 0000000000000003 R14: 0000000000000000 R15: 0000000000000000
 vring_interrupt+0x128/0x170 drivers/virtio/virtio_ring.c:950
 __handle_irq_event_percpu+0x1c8/0xaf0 kernel/irq/handle.c:149
 handle_irq_event_percpu+0xa0/0x1d0 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:native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:54
Code: c7 48 89 45 d8 e8 6a 91 27 fa 48 8b 45 d8 e9 d2 fe ff ff 48 89 df e8 59 91 27 fa eb 8a 90 90 90 90 90 90 90 55 48 89 e5 fb f4 <5d> c3 0f 1f 84 00 00 00 00 00 55 48 89 e5 f4 5d c3 90 90 90 90 90
RSP: 0000:ffffffff88e07bc0 EFLAGS: 00000286 ORIG_RAX: ffffffffffffffda
RAX: dffffc0000000000 RBX: 1ffffffff11c0f7b RCX: 0000000000000000
RDX: 1ffffffff11e3600 RSI: 0000000000000001 RDI: ffffffff88f1b000
RBP: ffffffff88e07bc0 R08: ffffed003b5c46d7 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffffffff88e07c78 R14: ffffffff899ea9e0 R15: 0000000000000000
 arch_safe_halt arch/x86/include/asm/paravirt.h:94 [inline]
 default_idle+0xc7/0x450 arch/x86/kernel/process.c:500
 arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:491
 default_idle_call+0x6d/0x90 kernel/sched/idle.c:93
 cpuidle_idle_call kernel/sched/idle.c:153 [inline]
 do_idle+0x3aa/0x570 kernel/sched/idle.c:262
 cpu_startup_entry+0x10c/0x120 kernel/sched/idle.c:368
 rest_init+0xe1/0xe4 init/main.c:442
 start_kernel+0x90e/0x949 init/main.c:738
 x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:452
 x86_64_start_kernel+0x76/0x79 arch/x86/kernel/head64.c:433
 secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:242
Modules linked in:
Dumping ftrace buffer:
   (ftrace buffer empty)

======================================================
WARNING: possible circular locking dependency detected
4.17.0+ #104 Not tainted
------------------------------------------------------
swapper/0/0 is trying to acquire lock:
(____ptrval____) ((console_sem).lock){-...}, at: down_trylock+0x13/0x70 kernel/locking/semaphore.c:136

but task is already holding lock:
(____ptrval____) (&p->pi_lock){-.-.}, at: try_to_wake_up+0xd2/0x12b0 kernel/sched/core.c:1986

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+0xd2/0x12b0 kernel/sched/core.c:1986
       wake_up_process+0x10/0x20 kernel/sched/core.c:2149
       __up.isra.1+0x1c0/0x2a0 kernel/locking/semaphore.c:262
       up+0x13c/0x1c0 kernel/locking/semaphore.c:187
       __up_console_sem+0xbe/0x1b0 kernel/printk/printk.c:242
       console_unlock+0x7a2/0x10b0 kernel/printk/printk.c:2411
       vprintk_emit+0x6c6/0xdf0 kernel/printk/printk.c:1907
       vprintk_default+0x28/0x30 kernel/printk/printk.c:1948
       vprintk_func+0x7a/0xe7 kernel/printk/printk_safe.c:382
       printk+0xa7/0xcf kernel/printk/printk.c:1981
       load_umh+0x51/0xbd net/bpfilter/bpfilter_kern.c:99
       do_one_initcall+0x127/0x913 init/main.c:884
       do_initcall_level init/main.c:952 [inline]
       do_initcalls init/main.c:960 [inline]
       do_basic_setup init/main.c:978 [inline]
       kernel_init_freeable+0x49b/0x58e init/main.c:1135
       kernel_init+0x11/0x1b3 init/main.c:1061
       ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412

-> #0 ((console_sem).lock){-...}:
       lock_acquire+0x1e4/0x540 kernel/locking/lockdep.c:3924
       __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:2230
       console_trylock_spinning kernel/printk/printk.c:1643 [inline]
       vprintk_emit+0x6ad/0xdf0 kernel/printk/printk.c:1906
       vprintk_default+0x28/0x30 kernel/printk/printk.c:1948
       vprintk_func+0x7a/0xe7 kernel/printk/printk_safe.c:382
       printk+0xa7/0xcf kernel/printk/printk.c:1981
       kasan_die_handler.cold.22+0x11/0x30 arch/x86/mm/kasan_init_64.c:251
       notifier_call_chain+0x180/0x390 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+0x1be/0x2e0 kernel/notifier.c:549
       do_general_protection+0x248/0x2f0 arch/x86/kernel/traps.c:559
       general_protection+0x1e/0x30 arch/x86/entry/entry_64.S:1159
       __delayacct_blkio_end+0x4f/0xc0 kernel/delayacct.c:83
       delayacct_blkio_end include/linux/delayacct.h:128 [inline]
       try_to_wake_up+0xacb/0x12b0 kernel/sched/core.c:2057
       default_wake_function+0x30/0x50 kernel/sched/core.c:3742
       autoremove_wake_function+0x80/0x370 kernel/sched/wait.c:373
       wake_bit_function+0xcb/0x160 kernel/sched/wait_bit.c:30
       __wake_up_common+0x191/0x740 kernel/sched/wait.c:90
       __wake_up_common_lock+0x1c2/0x330 kernel/sched/wait.c:119
       __wake_up+0xe/0x10 kernel/sched/wait.c:143
       __wake_up_bit+0x1af/0x290 kernel/sched/wait_bit.c:125
       wake_up_bit+0x3d/0x40 kernel/sched/wait_bit.c:148
       journal_end_buffer_io_sync+0xa4/0xe0 fs/jbd2/commit.c:44
       end_bio_bh_io_sync+0xf3/0x140 fs/buffer.c:2969
       bio_endio+0x530/0x9e0 block/bio.c:1836
       req_bio_endio block/blk-core.c:281 [inline]
       blk_update_request+0x3b2/0xcd0 block/blk-core.c:3091
       scsi_end_request+0xde/0x890 drivers/scsi/scsi_lib.c:672
       scsi_io_completion+0xcc6/0x1dd0 drivers/scsi/scsi_lib.c:898
       scsi_finish_command+0x54a/0x8f0 drivers/scsi/scsi.c:248
       scsi_softirq_done+0x3f6/0x4d0 drivers/scsi/scsi_lib.c:1687
       __blk_mq_complete_request block/blk-mq.c:583 [inline]
       blk_mq_complete_request+0x355/0x630 block/blk-mq.c:620
       scsi_mq_done+0xe7/0x450 drivers/scsi/scsi_lib.c:1998
       virtscsi_complete_cmd+0x573/0x740 drivers/scsi/virtio_scsi.c:207
       virtscsi_vq_done+0xcb/0x180 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+0x1c8/0xaf0 kernel/irq/handle.c:149
       handle_irq_event_percpu+0xa0/0x1d0 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
       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+0xc7/0x450 arch/x86/kernel/process.c:500
       arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:491
       default_idle_call+0x6d/0x90 kernel/sched/idle.c:93
       cpuidle_idle_call kernel/sched/idle.c:153 [inline]
       do_idle+0x3aa/0x570 kernel/sched/idle.c:262
       cpu_startup_entry+0x10c/0x120 kernel/sched/idle.c:368
       rest_init+0xe1/0xe4 init/main.c:442
       start_kernel+0x90e/0x949 init/main.c:738
       x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:452
       x86_64_start_kernel+0x76/0x79 arch/x86/kernel/head64.c:433
       secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:242

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 ***

4 locks held by swapper/0/0:
#0: (____ptrval____) (&(&virtscsi_vq->vq_lock)->rlock){-.-.}, at: virtscsi_vq_done+0xa5/0x180 drivers/scsi/virtio_scsi.c:219 #1: (____ptrval____) (bit_wait_table + i){-.-.}, at: __wake_up_common_lock+0x19e/0x330 kernel/sched/wait.c:118 #2: (____ptrval____) (&p->pi_lock){-.-.}, at: try_to_wake_up+0xd2/0x12b0 kernel/sched/core.c:1986 #3: (____ptrval____) (rcu_read_lock){....}, at: atomic_notifier_call_chain+0x0/0x190 kernel/notifier.c:329

stack backtrace:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.17.0+ #104
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+0x1c9/0x2b4 lib/dump_stack.c:113
print_circular_bug.isra.36.cold.56+0x1bd/0x27d kernel/locking/lockdep.c:1227
 check_prev_add kernel/locking/lockdep.c:1867 [inline]
 check_prevs_add kernel/locking/lockdep.c:1980 [inline]
 validate_chain kernel/locking/lockdep.c:2421 [inline]
 __lock_acquire+0x3449/0x5020 kernel/locking/lockdep.c:3435
 lock_acquire+0x1e4/0x540 kernel/locking/lockdep.c:3924
 __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:2230
 console_trylock_spinning kernel/printk/printk.c:1643 [inline]
 vprintk_emit+0x6ad/0xdf0 kernel/printk/printk.c:1906
 vprintk_default+0x28/0x30 kernel/printk/printk.c:1948
 vprintk_func+0x7a/0xe7 kernel/printk/printk_safe.c:382
 printk+0xa7/0xcf kernel/printk/printk.c:1981
 kasan_die_handler.cold.22+0x11/0x30 arch/x86/mm/kasan_init_64.c:251
 notifier_call_chain+0x180/0x390 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+0x1be/0x2e0 kernel/notifier.c:549
 do_general_protection+0x248/0x2f0 arch/x86/kernel/traps.c:559
 general_protection+0x1e/0x30 arch/x86/entry/entry_64.S:1159
RIP: 0010:__delayacct_blkio_end+0x4f/0xc0 kernel/delayacct.c:83
Code: 48 c1 ea 03 80 3c 02 00 0f 85 80 00 00 00 48 8b 9b 48 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 01
RSP: 0000:ffff8801dae06c28 EFLAGS: 00010002
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffff8801d9778538
RDX: 0000000000000007 RSI: ffffffff817cba01 RDI: 0000000000000038
RBP: ffff8801dae06c40 R08: ffffed003b5c46d7 R09: 0000000000000000
R10: ffff8801dae06d50 R11: ffff8801dae236b3 R12: ffffffff88e75dc0
R13: ffff8801d9778500 R14: ffff8801d977853c R15: 0000000000000002
 delayacct_blkio_end include/linux/delayacct.h:128 [inline]
 try_to_wake_up+0xacb/0x12b0 kernel/sched/core.c:2057
 default_wake_function+0x30/0x50 kernel/sched/core.c:3742
 autoremove_wake_function+0x80/0x370 kernel/sched/wait.c:373
 wake_bit_function+0xcb/0x160 kernel/sched/wait_bit.c:30
 __wake_up_common+0x191/0x740 kernel/sched/wait.c:90
 __wake_up_common_lock+0x1c2/0x330 kernel/sched/wait.c:119
 __wake_up+0xe/0x10 kernel/sched/wait.c:143
 __wake_up_bit+0x1af/0x290 kernel/sched/wait_bit.c:125
 wake_up_bit+0x3d/0x40 kernel/sched/wait_bit.c:148
 journal_end_buffer_io
Lost 167 message(s)!
---[ end trace 9ef680b141ad1ec6 ]---
RIP: 0010:__delayacct_blkio_end+0x4f/0xc0 kernel/delayacct.c:83
Code: 48 c1 ea 03 80 3c 02 00 0f 85 80 00 00 00 48 8b 9b 48 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 01
RSP: 0000:ffff8801dae06c28 EFLAGS: 00010002
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffff8801d9778538
RDX: 0000000000000007 RSI: ffffffff817cba01 RDI: 0000000000000038
RBP: ffff8801dae06c40 R08: ffffed003b5c46d7 R09: 0000000000000000
R10: ffff8801dae06d50 R11: ffff8801dae236b3 R12: ffffffff88e75dc0
R13: ffff8801d9778500 R14: ffff8801d977853c R15: 0000000000000002
FS:  0000000000000000(0000) GS:ffff8801dae00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000008e6a000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

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