syzbot

audit: type=1800 audit(1539961129.221:30): pid=5443 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="rmnologin" dev="sda1" ino=2423 res=0
ODEBUG: object 00000000945e43e1 is on stack 00000000e8e95b47, but NOT annotated.
WARNING: CPU: 0 PID: 5599 at lib/debugobjects.c:369 debug_object_is_on_stack lib/debugobjects.c:363 [inline]
WARNING: CPU: 0 PID: 5599 at lib/debugobjects.c:369 __debug_object_init.cold.14+0x51/0xdf lib/debugobjects.c:395
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 5599 Comm: syz-executor943 Not tainted 4.19.0-rc8-next-20181019+ #98
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x244/0x39d lib/dump_stack.c:113
 panic+0x2ad/0x55c kernel/panic.c:188
 __warn.cold.8+0x20/0x45 kernel/panic.c:540
 report_bug+0x254/0x2d0 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:178 [inline]
 do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271
 do_invalid_op+0x36/0x40 arch/x86/kernel/traps.c:290
 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:969
RIP: 0010:debug_object_is_on_stack lib/debugobjects.c:363 [inline]
RIP: 0010:__debug_object_init.cold.14+0x51/0xdf lib/debugobjects.c:395
Code: ea 03 80 3c 02 00 75 7c 49 8b 54 24 18 48 89 de 48 c7 c7 c0 f1 40 88 4c 89 85 d0 fd ff ff e8 09 8c d1 fd 4c 8b 85 d0 fd ff ff <0f> 0b e9 09 d6 ff ff 41 83 c4 01 b8 ff ff 37 00 44 89 25 b7 4e 66
RSP: 0018:ffff8801d8b57308 EFLAGS: 00010086
RAX: 0000000000000050 RBX: ffff8801d8b57af8 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff816585a5 RDI: 0000000000000005
RBP: ffff8801d8b57560 R08: ffff8801c4206978 R09: ffffed003b5c5008
R10: ffffed003b5c5008 R11: ffff8801dae28047 R12: ffff8801d8b4c500
R13: 00000000000cb680 R14: ffff8801d8b4c500 R15: ffff8801c4206968
 debug_object_init+0x16/0x20 lib/debugobjects.c:432
 debug_timer_init kernel/time/timer.c:704 [inline]
 debug_init kernel/time/timer.c:757 [inline]
 init_timer_key+0xa9/0x480 kernel/time/timer.c:806
 sock_init_data+0xe1/0xdc0 net/core/sock.c:2696
 bpf_prog_test_run_skb+0x255/0xc40 net/bpf/test_run.c:144
 bpf_prog_test_run+0x130/0x1a0 kernel/bpf/syscall.c:1790
 __do_sys_bpf kernel/bpf/syscall.c:2427 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:2371 [inline]
 __x64_sys_bpf+0x3d8/0x510 kernel/bpf/syscall.c:2371
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x440299
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffc937272b8 EFLAGS: 00000213 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440299
RDX: 0000000000000028 RSI: 0000000020000100 RDI: 000000000000000a
RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8
R10: 0000000000000000 R11: 0000000000000213 R12: 0000000000401b20
R13: 0000000000401bb0 R14: 0000000000000000 R15: 0000000000000000

======================================================
WARNING: possible circular locking dependency detected
4.19.0-rc8-next-20181019+ #98 Not tainted
------------------------------------------------------
syz-executor943/5599 is trying to acquire lock:
00000000322d4e98 ((console_sem).lock){-.-.}, at: down_trylock+0x13/0x70 kernel/locking/semaphore.c:136

but task is already holding lock:
000000007732fbdf (&obj_hash[i].lock){-.-.}, at: __debug_object_init+0x127/0x1290 lib/debugobjects.c:384

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&obj_hash[i].lock){-.-.}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x99/0xd0 kernel/locking/spinlock.c:152
       __debug_object_init+0x127/0x1290 lib/debugobjects.c:384
       debug_object_init+0x16/0x20 lib/debugobjects.c:432
       debug_hrtimer_init kernel/time/hrtimer.c:410 [inline]
       debug_init kernel/time/hrtimer.c:458 [inline]
       hrtimer_init+0x97/0x490 kernel/time/hrtimer.c:1308
       init_dl_task_timer+0x1b/0x50 kernel/sched/deadline.c:1057
       __sched_fork+0x2ae/0x590 kernel/sched/core.c:2166
       init_idle+0x75/0x740 kernel/sched/core.c:5382
       sched_init+0xb33/0xc02 kernel/sched/core.c:6065
       start_kernel+0x4be/0xa2b init/main.c:608
       x86_64_start_reservations+0x2e/0x30 arch/x86/kernel/head64.c:472
       x86_64_start_kernel+0x76/0x79 arch/x86/kernel/head64.c:451
       secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243

-> #2 (&rq->lock){-.-.}:
       __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
       _raw_spin_lock+0x2d/0x40 kernel/locking/spinlock.c:144
       rq_lock kernel/sched/sched.h:1127 [inline]
       task_fork_fair+0xb0/0x6d0 kernel/sched/fair.c:9768
       sched_fork+0x443/0xba0 kernel/sched/core.c:2359
       copy_process+0x2585/0x8770 kernel/fork.c:1887
       _do_fork+0x1cb/0x11c0 kernel/fork.c:2216
       kernel_thread+0x34/0x40 kernel/fork.c:2275
       rest_init+0x28/0x372 init/main.c:409
       arch_call_rest_init+0xe/0x1b
       start_kernel+0x9f0/0xa2b init/main.c:745
       x86_64_start_reservations+0x2e/0x30 arch/x86/kernel/head64.c:472
       x86_64_start_kernel+0x76/0x79 arch/x86/kernel/head64.c:451
       secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243

-> #1 (&p->pi_lock){-.-.}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x99/0xd0 kernel/locking/spinlock.c:152
       try_to_wake_up+0xd2/0x12e0 kernel/sched/core.c:1965
       wake_up_process+0x10/0x20 kernel/sched/core.c:2129
       __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:236
       console_unlock+0x80c/0x1190 kernel/printk/printk.c:2432
       vprintk_emit+0x391/0x990 kernel/printk/printk.c:1922
       vprintk_default+0x28/0x30 kernel/printk/printk.c:1964
       vprintk_func+0x7e/0x181 kernel/printk/printk_safe.c:398
       printk+0xa7/0xcf kernel/printk/printk.c:1997
       check_stack_usage kernel/exit.c:755 [inline]
       do_exit.cold.18+0x57/0x16f kernel/exit.c:916
       do_group_exit+0x177/0x440 kernel/exit.c:970
       __do_sys_exit_group kernel/exit.c:981 [inline]
       __se_sys_exit_group kernel/exit.c:979 [inline]
       __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:979
       do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
       entry_SYSCALL_64_after_hwframe+0x49/0xbe

-> #0 ((console_sem).lock){-.-.}:
       lock_acquire+0x1ed/0x520 kernel/locking/lockdep.c:3844
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x99/0xd0 kernel/locking/spinlock.c:152
       down_trylock+0x13/0x70 kernel/locking/semaphore.c:136
       __down_trylock_console_sem+0xae/0x1f0 kernel/printk/printk.c:219
       console_trylock+0x15/0xa0 kernel/printk/printk.c:2247
       console_trylock_spinning kernel/printk/printk.c:1653 [inline]
       vprintk_emit+0x372/0x990 kernel/printk/printk.c:1921
       vprintk_default+0x28/0x30 kernel/printk/printk.c:1964
       vprintk_func+0x7e/0x181 kernel/printk/printk_safe.c:398
       printk+0xa7/0xcf kernel/printk/printk.c:1997
       debug_object_is_on_stack lib/debugobjects.c:363 [inline]
       __debug_object_init.cold.14+0x4a/0xdf lib/debugobjects.c:395
       debug_object_init+0x16/0x20 lib/debugobjects.c:432
       debug_timer_init kernel/time/timer.c:704 [inline]
       debug_init kernel/time/timer.c:757 [inline]
       init_timer_key+0xa9/0x480 kernel/time/timer.c:806
       sock_init_data+0xe1/0xdc0 net/core/sock.c:2696
       bpf_prog_test_run_skb+0x255/0xc40 net/bpf/test_run.c:144
       bpf_prog_test_run+0x130/0x1a0 kernel/bpf/syscall.c:1790
       __do_sys_bpf kernel/bpf/syscall.c:2427 [inline]
       __se_sys_bpf kernel/bpf/syscall.c:2371 [inline]
       __x64_sys_bpf+0x3d8/0x510 kernel/bpf/syscall.c:2371
       do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
       entry_SYSCALL_64_after_hwframe+0x49/0xbe

other info that might help us debug this:

Chain exists of:
  (console_sem).lock --> &rq->lock --> &obj_hash[i].lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&obj_hash[i].lock);
                               lock(&rq->lock);
                               lock(&obj_hash[i].lock);
  lock((console_sem).lock);

 *** DEADLOCK ***

1 lock held by syz-executor943/5599:
 #0: 000000007732fbdf (&obj_hash[i].lock){-.-.}, at: __debug_object_init+0x127/0x1290 lib/debugobjects.c:384

stack backtrace:
CPU: 0 PID: 5599 Comm: syz-executor943 Not tainted 4.19.0-rc8-next-20181019+ #98
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x244/0x39d lib/dump_stack.c:113
 print_circular_bug.isra.35.cold.54+0x1bd/0x27d kernel/locking/lockdep.c:1221
 check_prev_add kernel/locking/lockdep.c:1863 [inline]
 check_prevs_add kernel/locking/lockdep.c:1976 [inline]
 validate_chain kernel/locking/lockdep.c:2347 [inline]
 __lock_acquire+0x3399/0x4c20 kernel/locking/lockdep.c:3341
 lock_acquire+0x1ed/0x520 kernel/locking/lockdep.c:3844
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0x99/0xd0 kernel/locking/spinlock.c:152
 down_trylock+0x13/0x70 kernel/locking/semaphore.c:136
 __down_trylock_console_sem+0xae/0x1f0 kernel/printk/printk.c:219
 console_trylock+0x15/0xa0 kernel/printk/printk.c:2247
 console_trylock_spinning kernel/printk/printk.c:1653 [inline]
 vprintk_emit+0x372/0x990 kernel/printk/printk.c:1921
 vprintk_default+0x28/0x30 kernel/printk/printk.c:1964
 vprintk_func+0x7e/0x181 kernel/printk/printk_safe.c:398
 printk+0xa7/0xcf kernel/printk/printk.c:1997
 debug_object_is_on_stack lib/debugobjects.c:363 [inline]
 __debug_object_init.cold.14+0x4a/0xdf lib/debugobjects.c:395
 debug_object_init+0x16/0x20 lib/debugobjects.c:432
 debug_timer_init kernel/time/timer.c:704 [inline]
 debug_init kernel/time/timer.c:757 [inline]
 init_timer_key+0xa9/0x480 kernel/time/timer.c:806
 sock_init_data+0xe1/0xdc0 net/core/sock.c:2696
 bpf_prog_test_run_skb+0x255/0xc40 net/bpf/test_run.c:144
 bpf_prog_test_run+0x130/0x1a0 kernel/bpf/syscall.c:1790
 __do_sys_bpf kernel/bpf/syscall.c:2427 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:2371 [inline]
 __x64_sys_bpf+0x3d8/0x510 kernel/bpf/syscall.c:2371
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x440299
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffc937272b8 EFLAGS: 00000213 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440299
RDX: 0000000000000028 RSI: 0000000020000100 RDI: 000000000000000a
RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8
R10: 0000000000000000 R11: 0000000000000213 R12: 0000000000401b20
R13: 0000000000401bb0 R14: 0000000000000000 R15: 0000000000000000
Kernel Offset: disabled
Rebooting in 86400 seconds..