Subject: BUG: free active (active state 0) object type: work_struct hint: strp_work

From: syzbot <[email-masked]>
Date: Thu, 04 Jan 2018 04:10:51 -0800

Hello,

syzkaller hit the following crash on  
6bb8824732f69de0f233ae6b1a8158e149627b38
git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git/master
compiler: gcc (GCC) 7.1.1 20170620
.config is attached
Raw console output is attached.
Unfortunately, I don't have any reproducer for this bug yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: [email-masked]
It will help syzbot understand when the bug is fixed. See footer for  
details.
If you forward the report, please keep this part and the footer.

Use struct sctp_assoc_value instead
sctp: [Deprecated]: syz-executor4 (pid 12483) Use of int in maxseg socket  
option.
Use struct sctp_assoc_value instead
------------[ cut here ]------------
ODEBUG: free active (active state 0) object type: work_struct hint:  
strp_work+0x0/0xf0 net/strparser/strparser.c:381
WARNING: CPU: 1 PID: 3502 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: 3502 Comm: kworker/u4:4 Not tainted 4.15.0-rc5+ #170
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Workqueue: kkcmd kcm_tx_work
Call Trace:
  __dump_stack lib/dump_stack.c:17 [inline]
  dump_stack+0x194/0x257 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+0x22/0x40 arch/x86/entry/entry_64.S:1061
RIP: 0010:debug_print_object+0x166/0x220 lib/debugobjects.c:288
RSP: 0018:ffff8801c0ee7068 EFLAGS: 00010086
RAX: dffffc0000000008 RBX: 0000000000000003 RCX: ffffffff8159bc3e
RDX: 0000000000000000 RSI: 1ffff100381dcdc8 RDI: ffff8801db317dd0
RBP: ffff8801c0ee70a8 R08: 0000000000000000 R09: 1ffff100381dcd9a
R10: ffffed00381dce3c R11: ffffffff86137ad8 R12: 0000000000000001
R13: ffffffff86113480 R14: ffffffff8560dc40 R15: ffffffff8146e5f0
  __debug_check_no_obj_freed lib/debugobjects.c:745 [inline]
  debug_check_no_obj_freed+0x662/0xf1f lib/debugobjects.c:774
  kmem_cache_free+0x253/0x2a0 mm/slab.c:3745
  unreserve_psock+0x5a1/0x780 net/kcm/kcmsock.c:547
  kcm_write_msgs+0xbae/0x1b80 net/kcm/kcmsock.c:590
  kcm_tx_work+0x2e/0x190 net/kcm/kcmsock.c:731
  process_one_work+0xbbf/0x1b10 kernel/workqueue.c:2112
  worker_thread+0x223/0x1990 kernel/workqueue.c:2246
  kthread+0x33c/0x400 kernel/kthread.c:238
  ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:515

======================================================
WARNING: possible circular locking dependency detected
4.15.0-rc5+ #170 Not tainted
------------------------------------------------------
kworker/u4:4/3502 is trying to acquire lock:
  ((console_sem).lock){-.-.}, at: [<0000000091214b42>]  
down_trylock+0x13/0x70 kernel/locking/semaphore.c:136

but task is already holding lock:
  (&obj_hash[i].lock){-.-.}, at: [<00000000da143489>]  
__debug_check_no_obj_freed lib/debugobjects.c:736 [inline]
  (&obj_hash[i].lock){-.-.}, at: [<00000000da143489>]  
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:396 [inline]
        debug_init kernel/time/hrtimer.c:441 [inline]
        hrtimer_init+0x8c/0x410 kernel/time/hrtimer.c:1122
        init_dl_task_timer+0x1b/0x50 kernel/sched/deadline.c:1023
        __sched_fork+0x2c4/0xb70 kernel/sched/core.c:2188
        init_idle+0x75/0x820 kernel/sched/core.c:5279
        sched_init+0xb19/0xc43 kernel/sched/core.c:5976
        start_kernel+0x452/0x819 init/main.c:582
        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:1766 [inline]
        task_fork_fair+0x7a/0x690 kernel/sched/fair.c:9449
        sched_fork+0x435/0xc00 kernel/sched/core.c:2404
        copy_process.part.38+0x174b/0x4b20 kernel/fork.c:1722
        copy_process kernel/fork.c:1565 [inline]
        _do_fork+0x1f7/0xfe0 kernel/fork.c:2044
        kernel_thread+0x34/0x40 kernel/fork.c:2106
        rest_init+0x22/0xf0 init/main.c:401
        start_kernel+0x7f1/0x819 init/main.c:713
        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/0x1600 kernel/sched/core.c:1988
        wake_up_process+0x10/0x20 kernel/sched/core.c:2151
        __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:245
        console_unlock+0x538/0xd80 kernel/printk/printk.c:2248
        do_con_write+0x106e/0x1f70 drivers/tty/vt/vt.c:2433
        con_write+0x25/0xb0 drivers/tty/vt/vt.c:2782
        do_output_char+0x4d9/0x7a0 drivers/tty/n_tty.c:431
        process_output drivers/tty/n_tty.c:498 [inline]
        n_tty_write+0x68d/0xec0 drivers/tty/n_tty.c:2314
        do_tty_write drivers/tty/tty_io.c:949 [inline]
        tty_write+0x3fa/0x840 drivers/tty/tty_io.c:1033
        __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
        entry_SYSCALL_64_fastpath+0x1f/0x96

-> #0 ((console_sem).lock){-.-.}:
        lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:3914
        __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:228
        console_trylock+0x15/0x100 kernel/printk/printk.c:2065
        vprintk_emit+0x49b/0x590 kernel/printk/printk.c:1756
        vprintk_default+0x28/0x30 kernel/printk/printk.c:1796
        vprintk_func+0x57/0xc0 kernel/printk/printk_safe.c:379
        printk+0xaa/0xca kernel/printk/printk.c:1829
        __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
        kmem_cache_free+0x253/0x2a0 mm/slab.c:3745
        unreserve_psock+0x5a1/0x780 net/kcm/kcmsock.c:547
        kcm_write_msgs+0xbae/0x1b80 net/kcm/kcmsock.c:590
        kcm_tx_work+0x2e/0x190 net/kcm/kcmsock.c:731
        process_one_work+0xbbf/0x1b10 kernel/workqueue.c:2112
        worker_thread+0x223/0x1990 kernel/workqueue.c:2246
        kthread+0x33c/0x400 kernel/kthread.c:238
        ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:515

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 ***

5 locks held by kworker/u4:4/3502:
  #0:  ((wq_completion)"%s""kkcmd"){+.+.}, at: [<0000000030be6056>]  
process_one_work+0xaaf/0x1b10 kernel/workqueue.c:2083
  #1:  ((work_completion)(&kcm->tx_work)){+.+.}, at: [<0000000019ffb03c>]  
process_one_work+0xb01/0x1b10 kernel/workqueue.c:2087
  #2:  (sk_lock-AF_KCM){+.+.}, at: [<0000000077d44615>] lock_sock  
include/net/sock.h:1462 [inline]
  #2:  (sk_lock-AF_KCM){+.+.}, at: [<0000000077d44615>]  
kcm_tx_work+0x26/0x190 net/kcm/kcmsock.c:726
  #3:  (&(&mux->lock)->rlock){+...}, at: [<00000000c908a2e7>] spin_lock_bh  
include/linux/spinlock.h:315 [inline]
  #3:  (&(&mux->lock)->rlock){+...}, at: [<00000000c908a2e7>]  
unreserve_psock+0x9e/0x780 net/kcm/kcmsock.c:521
  #4:  (&obj_hash[i].lock){-.-.}, at: [<00000000da143489>]  
__debug_check_no_obj_freed lib/debugobjects.c:736 [inline]
  #4:  (&obj_hash[i].lock){-.-.}, at: [<00000000da143489>]  
debug_check_no_obj_freed+0x1e9/0xf1f lib/debugobjects.c:774

stack backtrace:
CPU: 1 PID: 3502 Comm: kworker/u4:4 Not tainted 4.15.0-rc5+ #170
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Workqueue: kkcmd kcm_tx_work
Call Trace:
  __dump_stack lib/dump_stack.c:17 [inline]
  dump_stack+0x194/0x257 lib/dump_stack.c:53
  print_circular_bug.isra.37+0x2cd/0x2dc kernel/locking/lockdep.c:1218
  check_prev_add kernel/locking/lockdep.c:1858 [inline]
  check_prevs_add kernel/locking/lockdep.c:1971 [inline]
  validate_chain kernel/locking/lockdep.c:2412 [inline]
  __lock_acquire+0x30a8/0x3e00 kernel/locking/lockdep.c:3426
  lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:3914
  __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:228
  console_trylock+0x15/0x100 kernel/printk/printk.c:2065
  vprintk_emit+0x49b/0x590 kernel/printk/printk.c:1756
  vprintk_default+0x28/0x30 kernel/printk/printk.c:1796
  vprintk_func+0x57/0xc0 kernel/printk/printk_safe.c:379
  printk+0xaa/0xca kernel/printk/printk.c:1829
  __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
  kmem_cache_free+0x253/0x2a0 mm/slab.c:3745
  unreserve_psock+0x5a1/0x780 net/kcm/kcmsock.c:547
  kcm_write_msgs+0xbae/0x1b80 net/kcm/kcmsock.c:590
  kcm_tx_work+0x2e/0x190 net/kcm/kcmsock.c:731
  process_one_work+0xbbf/0x1b10 kernel/workqueue.c:2112
  worker_thread+0x223/0x1990 kernel/workqueue.c:2246
  kthread+0x33c/0x400 kernel/kthread.c:238
  ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:515
Shutting down cpus with NMI
Dumping ftrace buffer:
    (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..

---
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