general protection fault in debug_check_no_obj_freed

[syzbot]

Hello,

syzbot hit the following crash on upstream commit
bcfc1f4554662d8f2429ac8bd96064a59c149754 (Sat Mar 24 16:50:12 2018 +0000)
Merge tag 'pinctrl-v4.16-3' of
git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl
syzbot dashboard link:
https://syzkaller.appspot.com/bug?extid=fb828c6152023b75a42b

So far this crash happened 2 times on upstream.
Unfortunately, I don't have any reproducer for this crash yet.
Raw console output:
https://syzkaller.appspot.com/x/log.txt?id=5364406829449216
Kernel config:
https://syzkaller.appspot.com/x/.config?id=-5034017172441945317
compiler: gcc (GCC) 7.1.1 20170620
CC: [aarc...@redhat.com ak...@linux-foundation.org dan.j.w...@intel.com
del...@gmx.de hu...@google.com linux-...@vger.kernel.org
linu...@kvack.org mho...@suse.com ol...@redhat.com]

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+fb828c...@syzkaller.appspotmail.com
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.

kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
kasan: CONFIG_KASAN_INLINE enabled
general protection fault: 0000 [#1] SMP KASAN
kasan: GPF could be caused by NULL-ptr deref or user memory access
Dumping ftrace buffer:
(ftrace buffer empty)
Modules linked in:
CPU: 1 PID: 6842 Comm: syz-executor6 Not tainted 4.16.0-rc6+ #1
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
RIP: 0010:__debug_check_no_obj_freed lib/debugobjects.c:737 [inline]
RIP: 0010:debug_check_no_obj_freed+0x239/0xf1f lib/debugobjects.c:774
RSP: 0018:ffff88016ec46fc8 EFLAGS: 00010002
RAX: 0000000000000009 RBX: 078e0401078e0401 RCX: 0000000000000082
RDX: 00f1c08020f1c080 RSI: 1ffff10032698561 RDI: ffff8801934c2b08
RBP: ffff88016ec47198 R08: 1ffff1002dd88d37 R09: ffff8801cf4c8ca0
R10: ffffed002dd88e1e R11: ffff8801cf4c8d68 R12: ffffed002dd88e0e
R13: ffff88016ec47170 R14: 078e0401078e0401 R15: dffffc0000000000
FS: 00007f126fd20700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd936d15db8 CR3: 0000000006e22003 CR4: 00000000001606e0
DR0: 0000000020000000 DR1: 0000000020000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
kmem_cache_free+0x24c/0x2a0 mm/slab.c:3742
remove_vma+0x162/0x1b0 mm/mmap.c:176
exit_mmap+0x311/0x500 mm/mmap.c:3049
__mmput kernel/fork.c:960 [inline]
mmput+0x223/0x6d0 kernel/fork.c:981
exit_mm kernel/exit.c:544 [inline]
do_exit+0x90a/0x1ad0 kernel/exit.c:852
do_group_exit+0x149/0x400 kernel/exit.c:968
get_signal+0x73a/0x16d0 kernel/signal.c:2469
do_signal+0x90/0x1e90 arch/x86/kernel/signal.c:809
exit_to_usermode_loop+0x258/0x2f0 arch/x86/entry/common.c:162
prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline]
syscall_return_slowpath arch/x86/entry/common.c:265 [inline]
do_syscall_64+0x6ec/0x940 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x454879
RSP: 002b:00007f126fd1fce8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 000000000072bf80 RCX: 0000000000454879
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000000072bf80
RBP: 000000000072bf80 R08: 0000000000000000 R09: 000000000072bf58
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffd49a7a50f R14: 00007f126fd209c0 R15: 0000000000000001
Code: 4d 85 f6 0f 84 d7 04 00 00 4d 8d 55 80 4c 8b 9d 80 fe ff ff 4c 8b 8d
88 fe ff ff 31 c0 49 c1 ea 03 4d 01 fa 4c 89 f2 48 c1 ea 03 <42> 80 3c 3a
00 0f 85 06 05 00 00 49 8d 7e 18 83 c0 01 49 8b 16
RIP: __debug_check_no_obj_freed lib/debugobjects.c:737 [inline] RSP:
ffff88016ec46fc8
RIP: debug_check_no_obj_freed+0x239/0xf1f lib/debugobjects.c:774 RSP:
ffff88016ec46fc8

======================================================
WARNING: possible circular locking dependency detected
4.16.0-rc6+ #1 Not tainted
------------------------------------------------------
syz-executor6/6842 is trying to acquire lock:
((console_sem).lock){-.-.}, at: [<00000000936a11ae>]
down_trylock+0x13/0x70 kernel/locking/semaphore.c:136

but task is already holding lock:
(&obj_hash[i].lock){-.-.}, at: [<000000001e00f428>]
__debug_check_no_obj_freed lib/debugobjects.c:736 [inline]
(&obj_hash[i].lock){-.-.}, at: [<000000001e00f428>]
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:586
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:239

-> #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:403
start_kernel+0x7f1/0x819 init/main.c:717
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:239

-> #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
con_flush_chars+0x6e/0x80 drivers/tty/vt/vt.c:2863
n_tty_write+0x71b/0xec0 drivers/tty/n_tty.c:2325
do_tty_write drivers/tty/tty_io.c:958 [inline]
tty_write+0x3fa/0x840 drivers/tty/tty_io.c:1042
__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
do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287
entry_SYSCALL_64_after_hwframe+0x42/0xb7

-> #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
kasan_die_handler+0x31/0x3f arch/x86/mm/kasan_init_64.c:247
notifier_call_chain+0x136/0x2c0 kernel/notifier.c:93
__atomic_notifier_call_chain kernel/notifier.c:183 [inline]
atomic_notifier_call_chain+0x77/0x140 kernel/notifier.c:193
notify_die+0x18c/0x280 kernel/notifier.c:549
do_general_protection+0x331/0x3e0 arch/x86/kernel/traps.c:558
general_protection+0x25/0x50 arch/x86/entry/entry_64.S:1150
__debug_check_no_obj_freed lib/debugobjects.c:737 [inline]
debug_check_no_obj_freed+0x239/0xf1f lib/debugobjects.c:774
kmem_cache_free+0x24c/0x2a0 mm/slab.c:3742
remove_vma+0x162/0x1b0 mm/mmap.c:176
exit_mmap+0x311/0x500 mm/mmap.c:3049
__mmput kernel/fork.c:960 [inline]
mmput+0x223/0x6d0 kernel/fork.c:981
exit_mm kernel/exit.c:544 [inline]
do_exit+0x90a/0x1ad0 kernel/exit.c:852
do_group_exit+0x149/0x400 kernel/exit.c:968
get_signal+0x73a/0x16d0 kernel/signal.c:2469
do_signal+0x90/0x1e90 arch/x86/kernel/signal.c:809
exit_to_usermode_loop+0x258/0x2f0 arch/x86/entry/common.c:162
prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline]
syscall_return_slowpath arch/x86/entry/common.c:265 [inline]
do_syscall_64+0x6ec/0x940 arch/x86/entry/common.c:292
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 syz-executor6/6842:
#0: (&obj_hash[i].lock){-.-.}, at: [<000000001e00f428>]
__debug_check_no_obj_freed lib/debugobjects.c:736 [inline]
#0: (&obj_hash[i].lock){-.-.}, at: [<000000001e00f428>]
debug_check_no_obj_freed+0x1e9/0xf1f lib/debugobjects.c:774
#1: (rcu_read_lock){....}, at: [<000000008e0e18fc>] rcu_read_unlock
include/linux/rcupdate.h:682 [inline]
#1: (rcu_read_lock){....}, at: [<000000008e0e18fc>]
atomic_notifier_call_chain+0x0/0x140 kernel/notifier.c:184

stack backtrace:
CPU: 1 PID: 6842 Comm: syz-executor6 Not tainted 4.16.0-rc6+ #1
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
kasan_die_handler+0x31/0x3f arch/x86/mm/kasan_init_64.c:247
notifier_call_chain+0x136/0x2c0 kernel/notifier.c:93
__atomic_notifier_call_chain kernel/notifier.c:183 [inline]
atomic_notifier_call_chain+0x77/0x140 kernel/notifier.c:193
notify_die+0x18c/0x280 kernel/notifier.c:549
do_general_protection+0x331/0x3e0 arch/x86/kernel/traps.c:558
general_protection+0x25/0x50 arch/x86/entry/entry_64.S:1150
RIP: 0010:__debug_check_no_obj_freed lib/debugobjects.c:737 [inline]
RIP: 0010:debug_check_no_obj_freed+0x239/0xf1f lib/debugobjects.c:774
RSP: 0018:ffff88016ec46fc8 EFLAGS: 00010002
RAX: 0000000000000009 RBX: 078e0401078e0401 RCX: 0000000000000082
RDX: 00f1c08020f1c080 RSI: 1ffff10032698561 RDI: ffff8801934c2b08
RBP: ffff88016ec47198 R08: 1ffff1002dd88d37 R09: ffff8801cf4c8ca0
R10: ffffed002dd88e1e R11: ffff8801cf4c8d68 R12: ffffed002dd88e0e
R13: ffff88016ec47170 R14: 078e0401078e0401 R15: dffffc0000000000
kmem_cache_free+0x24c/0x2a0 mm/slab.c:3742
remove_vma+0x162/0x1b0 mm/mmap.c:176
exit_mmap+0x311/0x500 mm/mmap.c:3049
__mmput kernel/fork.c:960 [inline]
mmput+0x223/0x6d0 kernel/fork.c:981
exit_mm kernel/exit.c:544 [inline]
do_exit+0x90a/0x1ad0 kernel/exit.c:852
do_group_exit+0x149/0x400 kernel/exit.c:968
get_signal+0x73a/0x16d0 kernel/signal.c:2469
do_signal+0x90/0x1e90 arch/x86/kernel/signal.c:809
exit_to_usermode_loop+0x258/0x2f0 arch/x86/entry/common.c:162
? do_syscall
Lost 18 message(s)!
---[ end trace a5be101c0e3795fb ]---
general protection fault: 0000 [#2] SMP KASAN
Dumping ftrace buffer:


---
This bug is generated by a dumb bot. It may contain errors.
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[Dmitry Vyukov]

Happened twice 110 days ago, looks like memory corruption:

#syz invalid

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