[syzbot] WARNING: locking bug in netdev_unregister_kobject

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 9500fc6e9e60 Merge branch 'for-next/core' into for-kernelci
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=13d5f501880000
kernel config: https://syzkaller.appspot.com/x/.config?x=b25c9f218686dd5e
dashboard link: https://syzkaller.appspot.com/bug?extid=079faa8639c56206a713
compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: arm64

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/1363e60652f7/disk-9500fc6e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/fcc4da811bb6/vmlinux-9500fc6e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0b554298f1fa/Image-9500fc6e.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+079faa...@syzkaller.appspotmail.com

bond5 (unregistering): Released all slaves
------------[ cut here ]------------
DEBUG_LOCKS_WARN_ON(1)
WARNING: CPU: 1 PID: 3637 at kernel/locking/lockdep.c:231 check_wait_context kernel/locking/lockdep.c:4729 [inline]
WARNING: CPU: 1 PID: 3637 at kernel/locking/lockdep.c:231 __lock_acquire+0x2b0/0x3084 kernel/locking/lockdep.c:5005
Modules linked in:
CPU: 1 PID: 3637 Comm: kworker/u4:12 Not tainted 6.1.0-rc5-syzkaller-32269-g9500fc6e9e60 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/30/2022
Workqueue: netns cleanup_net
pstate: 604000c5 (nZCv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : check_wait_context kernel/locking/lockdep.c:4729 [inline]
pc : __lock_acquire+0x2b0/0x3084 kernel/locking/lockdep.c:5005
lr : hlock_class kernel/locking/lockdep.c:231 [inline]
lr : check_wait_context kernel/locking/lockdep.c:4729 [inline]
lr : __lock_acquire+0x298/0x3084 kernel/locking/lockdep.c:5005
sp : ffff800013ac38d0
x29: ffff800013ac39b0 x28: 0000000000000004 x27: ffff000105793520
x26: ffff000100eab228 x25: ffff000105793f28 x24: 0000000000000000
x23: 0000000000000000 x22: 0000000000000001 x21: 0000000000000000
x20: 0000000000000000 x19: aac6ab555542fdfe x18: 0000000000000000
x17: 0000000000000000 x16: ffff80000dc18158 x15: ffff000105793480
x14: 0000000000000000 x13: 0000000000000012 x12: ffff80000d96cfd0
x11: ff808000081c6510 x10: ffff80000ddda198 x9 : 9396706c2ea69400
x8 : 0000000000000000 x7 : 4e5241575f534b43 x6 : ffff80000c0b2b74
x5 : 0000000000000000 x4 : 0000000000000001 x3 : 0000000000000000
x2 : 0000000000000000 x1 : 0000000100000001 x0 : 0000000000000016
Call trace:
check_wait_context kernel/locking/lockdep.c:4729 [inline]
__lock_acquire+0x2b0/0x3084 kernel/locking/lockdep.c:5005
lock_acquire+0x100/0x1f8 kernel/locking/lockdep.c:5668
__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
_raw_spin_lock+0x54/0x6c kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:350 [inline]
kobj_kset_leave lib/kobject.c:174 [inline]
__kobject_del+0x9c/0x1f8 lib/kobject.c:592
kobject_cleanup+0xfc/0x280 lib/kobject.c:664
kobject_release lib/kobject.c:704 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x94/0xf8 lib/kobject.c:721
net_rx_queue_update_kobjects net/core/net-sysfs.c:1128 [inline]
remove_queue_kobjects net/core/net-sysfs.c:1829 [inline]
netdev_unregister_kobject+0x168/0x1d4 net/core/net-sysfs.c:1983
unregister_netdevice_many+0x730/0xa0c net/core/dev.c:10874
default_device_exit_batch+0x3c0/0x424 net/core/dev.c:11341
ops_exit_list net/core/net_namespace.c:174 [inline]
cleanup_net+0x3cc/0x648 net/core/net_namespace.c:601
process_one_work+0x2d8/0x504 kernel/workqueue.c:2289
worker_thread+0x340/0x610 kernel/workqueue.c:2436
kthread+0x12c/0x158 kernel/kthread.c:376
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:863
irq event stamp: 8362613
hardirqs last enabled at (8362613): [<ffff80000c0b7c04>] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline]
hardirqs last enabled at (8362613): [<ffff80000c0b7c04>] _raw_spin_unlock_irqrestore+0x48/0x8c kernel/locking/spinlock.c:194
hardirqs last disabled at (8362612): [<ffff80000c0b7a40>] __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:108 [inline]
hardirqs last disabled at (8362612): [<ffff80000c0b7a40>] _raw_spin_lock_irqsave+0xa4/0xb4 kernel/locking/spinlock.c:162
softirqs last enabled at (8362594): [<ffff80000b2a05fc>] spin_unlock_bh include/linux/spinlock.h:395 [inline]
softirqs last enabled at (8362594): [<ffff80000b2a05fc>] netif_addr_unlock_bh include/linux/netdevice.h:4454 [inline]
softirqs last enabled at (8362594): [<ffff80000b2a05fc>] dev_mc_flush+0xd4/0xec net/core/dev_addr_lists.c:1036
softirqs last disabled at (8362592): [<ffff80000b2a0660>] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:19
---[ end trace 0000000000000000 ]---
Unable to handle kernel NULL pointer dereference at virtual address 00000000000000b8
Mem abort info:
ESR = 0x0000000096000004
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x04: level 0 translation fault
Data abort info:
ISV = 0, ISS = 0x00000004
CM = 0, WnR = 0
user pgtable: 4k pages, 48-bit VAs, pgdp=0000000107c45000
[00000000000000b8] pgd=0000000000000000, p4d=0000000000000000
Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 3637 Comm: kworker/u4:12 Tainted: G W 6.1.0-rc5-syzkaller-32269-g9500fc6e9e60 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/30/2022
Workqueue: netns cleanup_net
pstate: 604000c5 (nZCv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : check_wait_context kernel/locking/lockdep.c:4729 [inline]
pc : __lock_acquire+0x2d0/0x3084 kernel/locking/lockdep.c:5005
lr : hlock_class kernel/locking/lockdep.c:231 [inline]
lr : check_wait_context kernel/locking/lockdep.c:4729 [inline]
lr : __lock_acquire+0x298/0x3084 kernel/locking/lockdep.c:5005
sp : ffff800013ac38d0
x29: ffff800013ac39b0 x28: 0000000000000004 x27: ffff000105793520
x26: ffff000100eab228 x25: ffff000105793f28 x24: 0000000000000000
x23: 0000000000000000 x22: 0000000000000001 x21: 0000000000000000
x20: 0000000000000000 x19: aac6ab555542fdfe x18: 0000000000000000
x17: 0000000000000000 x16: ffff80000dc18158 x15: ffff000105793480
x14: 0000000000000000 x13: 0000000000000012 x12: ffff80000d96cfd0
x11: ff808000081c6510 x10: ffff80000ddda198 x9 : 0000000000041dfe
x8 : 0000000000000000 x7 : 4e5241575f534b43 x6 : ffff80000c0b2b74
x5 : 0000000000000000 x4 : 0000000000000001 x3 : 0000000000000000
x2 : 0000000000000000 x1 : 0000000100000001 x0 : 0000000000000016
Call trace:
hlock_class kernel/locking/lockdep.c:222 [inline]
check_wait_context kernel/locking/lockdep.c:4730 [inline]
__lock_acquire+0x2d0/0x3084 kernel/locking/lockdep.c:5005
lock_acquire+0x100/0x1f8 kernel/locking/lockdep.c:5668
__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
_raw_spin_lock+0x54/0x6c kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:350 [inline]
kobj_kset_leave lib/kobject.c:174 [inline]
__kobject_del+0x9c/0x1f8 lib/kobject.c:592
kobject_cleanup+0xfc/0x280 lib/kobject.c:664
kobject_release lib/kobject.c:704 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x94/0xf8 lib/kobject.c:721
net_rx_queue_update_kobjects net/core/net-sysfs.c:1128 [inline]
remove_queue_kobjects net/core/net-sysfs.c:1829 [inline]
netdev_unregister_kobject+0x168/0x1d4 net/core/net-sysfs.c:1983
unregister_netdevice_many+0x730/0xa0c net/core/dev.c:10874
default_device_exit_batch+0x3c0/0x424 net/core/dev.c:11341
ops_exit_list net/core/net_namespace.c:174 [inline]
cleanup_net+0x3cc/0x648 net/core/net_namespace.c:601
process_one_work+0x2d8/0x504 kernel/workqueue.c:2289
worker_thread+0x340/0x610 kernel/workqueue.c:2436
kthread+0x12c/0x158 kernel/kthread.c:376
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:863
Code: d002e1ca 91056210 9106614a b9400329 (3942e114)
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
0: d002e1ca adrp x10, 0x5c3a000
4: 91056210 add x16, x16, #0x158
8: 9106614a add x10, x10, #0x198
c: b9400329 ldr w9, [x25]
* 10: 3942e114 ldrb w20, [x8, #184] <-- trapping instruction


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.