Date:   Sun, 25 Feb 2018 08:22:01 -0800
From:   syzbot <syzbot+d7deafa2c73b7a2b74ef@...kaller.appspotmail.com>
To:     coreteam@...filter.org, davem@...emloft.net, fw@...len.de,
        kadlec@...ckhole.kfki.hu, kuznet@....inr.ac.ru,
        linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
        netfilter-devel@...r.kernel.org, pablo@...filter.org,
        syzkaller-bugs@...glegroups.com, yoshfuji@...ux-ipv6.org
Subject: Re: WARNING: ODEBUG bug in do_ipt_get_ctl

syzbot has found reproducer for the following crash on net-next commit
f74290fdb363665538743d14c4f00aeacdb68d87 (Sat Feb 24 05:04:20 2018 +0000)
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

So far this crash happened 3 times on net-next, upstream.
C reproducer is attached.
syzkaller reproducer is attached.
Raw console output is attached.
compiler: gcc (GCC) 7.1.1 20170620
.config is attached.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+d7deafa2c73b7a2b74ef@...kaller.appspotmail.com
It will help syzbot understand when the bug is fixed.

------------[ cut here ]------------
ODEBUG: free active (active state 0) object type: timer_list hint:  
delayed_work_timer_fn+0x0/0x90 kernel/workqueue.c:1355
WARNING: CPU: 1 PID: 4244 at lib/debugobjects.c:291  
debug_print_object+0x166/0x220 lib/debugobjects.c:288
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 4244 Comm: syzkaller150583 Not tainted 4.16.0-rc2+ #241
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Call Trace:
  __dump_stack lib/dump_stack.c:17 [inline]
  dump_stack+0x194/0x24d lib/dump_stack.c:53
  panic+0x1e4/0x41c kernel/panic.c:183
  __warn+0x1dc/0x200 kernel/panic.c:547
  report_bug+0x211/0x2d0 lib/bug.c:184
  fixup_bug.part.11+0x37/0x80 arch/x86/kernel/traps.c:178
  fixup_bug arch/x86/kernel/traps.c:247 [inline]
  do_error_trap+0x2d7/0x3e0 arch/x86/kernel/traps.c:296
  do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:315
  invalid_op+0x58/0x80 arch/x86/entry/entry_64.S:957
RIP: 0010:debug_print_object+0x166/0x220 lib/debugobjects.c:288
RSP: 0018:ffff8801cc2c7778 EFLAGS: 00010082
RAX: dffffc0000000008 RBX: 0000000000000003 RCX: ffffffff815abe7e
RDX: 0000000000000000 RSI: 1ffff10039858e9f RDI: 1ffff10039858e74
RBP: ffff8801cc2c77b8 R08: 0000000000000000 R09: 1ffff10039858e46
R10: ffffed0039858f1e R11: ffffffff86f395b8 R12: 0000000000000001
R13: ffffffff86f4ae20 R14: ffffffff86407fa0 R15: ffffffff815fe8e0
  __debug_check_no_obj_freed lib/debugobjects.c:745 [inline]
  debug_check_no_obj_freed+0x662/0xf1f lib/debugobjects.c:774
  __vunmap+0x112/0x380 mm/vmalloc.c:1530
  vfree+0x50/0xe0 mm/vmalloc.c:1606
  copy_entries_to_user net/ipv4/netfilter/ip_tables.c:880 [inline]
  get_entries net/ipv4/netfilter/ip_tables.c:1035 [inline]
  do_ipt_get_ctl+0x7f5/0xac0 net/ipv4/netfilter/ip_tables.c:1708
  nf_sockopt net/netfilter/nf_sockopt.c:104 [inline]
  nf_getsockopt+0x6a/0xc0 net/netfilter/nf_sockopt.c:122
  ip_getsockopt+0x152/0x200 net/ipv4/ip_sockglue.c:1572
  tcp_getsockopt+0x82/0xd0 net/ipv4/tcp.c:3332
  sock_common_getsockopt+0x95/0xd0 net/core/sock.c:2938
  SYSC_getsockopt net/socket.c:1881 [inline]
  SyS_getsockopt+0x178/0x340 net/socket.c:1863
  do_syscall_64+0x280/0x940 arch/x86/entry/common.c:287
  entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x455faa
RSP: 002b:000000000080e8c8 EFLAGS: 00000216 ORIG_RAX: 0000000000000037
RAX: ffffffffffffffda RBX: 00000000006ea840 RCX: 0000000000455faa
RDX: 0000000000000041 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00000000006ea840 R08: 000000000080e8ec R09: 0000000000004000
R10: 000000000080e9f0 R11: 0000000000000216 R12: 0000000000000004
R13: 000000000080e9f0 R14: 000000000080e8f0 R15: 0000000000000000

======================================================
WARNING: possible circular locking dependency detected
4.16.0-rc2+ #241 Not tainted
------------------------------------------------------
syzkaller150583/4244 is trying to acquire lock:
  ((console_sem).lock){..-.}, at: [<000000003b3aa024>]  
down_trylock+0x13/0x70 kernel/locking/semaphore.c:136

but task is already holding lock:
  (&obj_hash[i].lock){-.-.}, at: [<00000000e7f32348>]  
__debug_check_no_obj_freed lib/debugobjects.c:736 [inline]
  (&obj_hash[i].lock){-.-.}, at: [<00000000e7f32348>]  
debug_check_no_obj_freed+0x1e9/0xf1f lib/debugobjects.c:774

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+0x96/0xc0 kernel/locking/spinlock.c:152
        __debug_object_init+0x109/0x1040 lib/debugobjects.c:343
        debug_object_init+0x17/0x20 lib/debugobjects.c:391
        debug_hrtimer_init kernel/time/hrtimer.c:410 [inline]
        debug_init kernel/time/hrtimer.c:458 [inline]
        hrtimer_init+0x8c/0x410 kernel/time/hrtimer.c:1259
        init_dl_task_timer+0x1b/0x50 kernel/sched/deadline.c:1060
        __sched_fork+0x2bb/0xb60 kernel/sched/core.c:2189
        init_idle+0x75/0x820 kernel/sched/core.c:5352
        sched_init+0xb19/0xc43 kernel/sched/core.c:6049
        start_kernel+0x452/0x819 init/main.c:585
        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:237

-> #2 (&rq->lock){-.-.}:
        __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
        _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:144
        rq_lock kernel/sched/sched.h:1760 [inline]
        task_fork_fair+0x7a/0x690 kernel/sched/fair.c:9471
        sched_fork+0x450/0xc10 kernel/sched/core.c:2405
        copy_process.part.38+0x1758/0x4b60 kernel/fork.c:1763
        copy_process kernel/fork.c:1606 [inline]
        _do_fork+0x1f7/0xf70 kernel/fork.c:2087
        kernel_thread+0x34/0x40 kernel/fork.c:2146
        rest_init+0x22/0xf0 init/main.c:402
        start_kernel+0x7f1/0x819 init/main.c:716
        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:237

-> #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
        vprintk_emit+0x5c3/0xb90 kernel/printk/printk.c:1907
        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
        kauditd_printk_skb kernel/audit.c:506 [inline]
        kauditd_hold_skb+0x163/0x180 kernel/audit.c:539
        kauditd_send_queue+0xfa/0x140 kernel/audit.c:702
        kauditd_thread+0x660/0x940 kernel/audit.c:828
        kthread+0x33c/0x400 kernel/kthread.c:238
        ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:407

-> #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
        __warn_printk+0x90/0xf0 kernel/panic.c:599
        debug_print_object+0x166/0x220 lib/debugobjects.c:288
        __debug_check_no_obj_freed lib/debugobjects.c:745 [inline]
        debug_check_no_obj_freed+0x662/0xf1f lib/debugobjects.c:774
        __vunmap+0x112/0x380 mm/vmalloc.c:1530
        vfree+0x50/0xe0 mm/vmalloc.c:1606
        copy_entries_to_user net/ipv4/netfilter/ip_tables.c:880 [inline]
        get_entries net/ipv4/netfilter/ip_tables.c:1035 [inline]
        do_ipt_get_ctl+0x7f5/0xac0 net/ipv4/netfilter/ip_tables.c:1708
        nf_sockopt net/netfilter/nf_sockopt.c:104 [inline]
        nf_getsockopt+0x6a/0xc0 net/netfilter/nf_sockopt.c:122
        ip_getsockopt+0x152/0x200 net/ipv4/ip_sockglue.c:1572
        tcp_getsockopt+0x82/0xd0 net/ipv4/tcp.c:3332
        sock_common_getsockopt+0x95/0xd0 net/core/sock.c:2938
        SYSC_getsockopt net/socket.c:1881 [inline]
        SyS_getsockopt+0x178/0x340 net/socket.c:1863
        do_syscall_64+0x280/0x940 arch/x86/entry/common.c:287
        entry_SYSCALL_64_after_hwframe+0x42/0xb7

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 ***

2 locks held by syzkaller150583/4244:
  #0:  (&xt[i].mutex){+.+.}, at: [<00000000806f2582>]  
xt_find_table_lock+0x3e/0x3e0 net/netfilter/x_tables.c:1040
  #1:  (&obj_hash[i].lock){-.-.}, at: [<00000000e7f32348>]  
__debug_check_no_obj_freed lib/debugobjects.c:736 [inline]
  #1:  (&obj_hash[i].lock){-.-.}, at: [<00000000e7f32348>]  
debug_check_no_obj_freed+0x1e9/0xf1f lib/debugobjects.c:774

stack backtrace:
CPU: 1 PID: 4244 Comm: syzkaller150583 Not tainted 4.16.0-rc2+ #241
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Call Trace:
  __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
  __warn_printk+0x90/0xf0 kernel/panic.c:599
  debug_print_object+0x166/0x220 lib/debugobjects.c:288
  __debug_check_no_obj_freed lib/debugobjects.c:745 [inline]
  debug_check_no_obj_freed+0x662/0xf1f lib/debugobjects.c:774
  __vunmap+0x112/0x380 mm/vmalloc.c:1530
  vfree+0x50/0xe0 mm/vmalloc.c:1606
  copy_entries_to_user net/ipv4/netfilter/ip_tables.c:880 [inline]
  get_entries net/ipv4/netfilter/ip_tables.c:1035 [inline]
  do_ipt_get_ctl+0x7f5/0xac0 net/ipv4/netfilter/ip_tables.c:1708
  nf_sockopt net/netfilter/nf_sockopt.c:104 [inline]
  nf_getsockopt+0x6a/0xc0 net/netfilter/nf_sockopt.c:122
  ip_getsockopt+0x152/0x200 net/ipv4/ip_sockglue.c:1572
  tcp_getsockopt+0x82/0xd0 net/ipv4/tcp.c:3332
  sock_common_getsockopt+0x95/0xd0 net/core/sock.c:2938
  SYSC_getsockopt net/socket.c:1881 [inline]
  SyS_getsockopt+0x178/0x340 net/socket.c:1863
  do_syscall_64+0x280/0x940 arch/x86/entry/common.c:287
  entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x455faa
RSP: 002b:000000000080e8c8 EFLAGS: 00000216 ORIG_RAX: 0000000000000037
RAX: ffffffffffffffda RBX: 00000000006ea840 RCX: 0000000000455faa
RDX: 0000000000000041 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00000000006ea840 R08: 000000000080e8ec R09: 0000000000004000
R10: 000000000080e9f0 R11: 0000000000000216 R12: 0000000000000004
R13: 000000000080e9f0 R14: 000000000080e8f0 R15: 0000000000000000
Dumping ftrace buffer:
    (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..


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