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Date:   Sat, 27 Oct 2018 20:18:03 -0700
Message-ID: <0000000000008db3210579416691@google.com>
Subject: WARNING in __debug_object_init (3)
From:   syzbot <syzbot+6e682caa546b7c96c859@syzkaller.appspotmail.com>
To:     ast@kernel.org, daniel@iogearbox.net, davem@davemloft.net,
        linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
        syzkaller-bugs@googlegroups.com
Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes
Sender: linux-kernel-owner@vger.kernel.org
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Hello,

syzbot found the following crash on:

HEAD commit:    8c60c36d0b8c Add linux-next specific files for 20181019
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=100feec5400000
kernel config:  https://syzkaller.appspot.com/x/.config?x=8b6d7c4c81535e89
dashboard link: https://syzkaller.appspot.com/bug?extid=6e682caa546b7c96c859
compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=13579abd400000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=13654f6b400000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+6e682caa546b7c96c859@syzkaller.appspotmail.com

ODEBUG: object 0000000015e9012c is on stack 00000000115bcb67, but NOT  
annotated.
WARNING: CPU: 0 PID: 5594 at lib/debugobjects.c:369  
debug_object_is_on_stack lib/debugobjects.c:363 [inline]
WARNING: CPU: 0 PID: 5594 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: 5594 Comm: syz-executor740 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:ffff8801bb387308 EFLAGS: 00010086
RAX: 0000000000000050 RBX: ffff8801bb387af8 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff816585a5 RDI: 0000000000000005
RBP: ffff8801bb387560 R08: ffff8801cb208a20 R09: ffffed003b5c5008
R10: ffffed003b5c5008 R11: ffff8801dae28047 R12: ffff8801d82ea300
R13: 0000000000069700 R14: ffff8801d82ea300 R15: ffff8801cb208a10
  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: 0033:0x440259
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:00007ffc212cf818 EFLAGS: 00000213 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440259
RDX: 0000000000000028 RSI: 0000000020000080 RDI: 000000000000000a
RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8
R10: 0000000000000000 R11: 0000000000000213 R12: 0000000000401ae0
R13: 0000000000401b70 R14: 0000000000000000 R15: 0000000000000000

======================================================
WARNING: possible circular locking dependency detected
4.19.0-rc8-next-20181019+ #98 Not tainted
------------------------------------------------------
syz-executor740/5594 is trying to acquire lock:
00000000688fcc6b ((console_sem).lock){-.-.}, at: down_trylock+0x13/0x70  
kernel/locking/semaphore.c:136

but task is already holding lock:
00000000505ead1b (&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-executor740/5594:
  #0: 00000000505ead1b (&obj_hash[i].lock){-.-.}, at:  
__debug_object_init+0x127/0x1290 lib/debugobjects.c:384

stack backtrace:
CPU: 0 PID: 5594 Comm: syz-executor740 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: 0033:0x440259
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:00007ffc212cf818 EFLAGS: 00000213 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440259
RDX: 0000000000000028 RSI: 0000000020000080 RDI: 000000000000000a
RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8
R10: 0000000000000000 R11: 0000000000000213 R12: 0000000000401ae0
R13: 0000000000401b70 R14: 0000000000000000 R15: 0000000000000000
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
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