general protection fault in rb_next (2)

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: edeca3a769ad Merge tag 'sound-4.20-rc4' of git://git.kerne..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13316f7b400000
kernel config: https://syzkaller.appspot.com/x/.config?x=73e2bc0cb6463446
dashboard link: https://syzkaller.appspot.com/bug?extid=563bb80fa8765090bf16
compiler: gcc (GCC) 8.0.1 20180413 (experimental)

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

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+563bb8...@syzkaller.appspotmail.com

bond0 (unregistering): Releasing backup interface bond_slave_0
bond0 (unregistering): Released all slaves
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 160 Comm: kworker/u4:3 Not tainted 4.20.0-rc3+ #125
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Workqueue: netns cleanup_net
RIP: 0010:rb_next+0xd7/0x140 lib/rbtree.c:541
Code: 49 89 dc 4c 89 eb 48 83 e3 fc 48 89 d8 75 c8 48 83 c4 08 5b 41 5c 41
5d 41 5e 5d c3 48 89 d0 48 8d 78 10 48 89 fa 48 c1 ea 03 <80> 3c 1a 00 75
1a 48 8b 50 10 48 85 d2 75 e3 48 83 c4 08 5b 41 5c
RSP: 0018:ffff8881d930ebc8 EFLAGS: 00010203
RAX: 5741e5894855dfff RBX: dffffc0000000000 RCX: ffffffff81f8d010
RDX: 0ae83cb1290abc01 RSI: ffffffff81f8cee0 RDI: 5741e5894855e00f
RBP: ffff8881d930ebf0 R08: ffff8881d92fc480 R09: fffffbfff0fab697
R10: fffffbfff0fab697 R11: ffffffff87d5b4bf R12: ffffffff87d5b4f0
R13: fc0000000000ba48 R14: dffffc0000000000 R15: 0000000000000004
FS: 0000000000000000(0000) GS:ffff8881daf00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000402e9d CR3: 000000017cbad000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
kernfs_next_descendant_post+0x89/0x2e0 fs/kernfs/dir.c:1235
__kernfs_remove+0x178/0xaf0 fs/kernfs/dir.c:1295
kernfs_remove+0x23/0x40 fs/kernfs/dir.c:1353
sysfs_remove_dir+0xd6/0x110 fs/sysfs/dir.c:101
kobject_del.part.4+0x3a/0xf0 lib/kobject.c:592
kobject_del lib/kobject.c:588 [inline]
kobject_cleanup lib/kobject.c:656 [inline]
kobject_release lib/kobject.c:691 [inline]
kref_put include/linux/kref.h:70 [inline]
kobject_put.cold.9+0x1f0/0x2e4 lib/kobject.c:708
netdev_queue_update_kobjects+0x312/0x4f0 net/core/net-sysfs.c:1513
remove_queue_kobjects net/core/net-sysfs.c:1563 [inline]
netdev_unregister_kobject+0x1ff/0x2e0 net/core/net-sysfs.c:1713
rollback_registered_many+0x8d4/0x1250 net/core/dev.c:8030
unregister_netdevice_many+0xfa/0x4c0 net/core/dev.c:9111
default_device_exit_batch+0x43a/0x540 net/core/dev.c:9580
ops_exit_list.isra.5+0x105/0x160 net/core/net_namespace.c:156
cleanup_net+0x555/0xb10 net/core/net_namespace.c:551
process_one_work+0xc90/0x1c40 kernel/workqueue.c:2153
worker_thread+0x17f/0x1390 kernel/workqueue.c:2296
kthread+0x35a/0x440 kernel/kthread.c:246
ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352
Modules linked in:
---[ end trace 0076ea0e5672f55d ]---
RIP: 0010:rb_next+0xd7/0x140 lib/rbtree.c:541
Code: 49 89 dc 4c 89 eb 48 83 e3 fc 48 89 d8 75 c8 48 83 c4 08 5b 41 5c 41
5d 41 5e 5d c3 48 89 d0 48 8d 78 10 48 89 fa 48 c1 ea 03 <80> 3c 1a 00 75
1a 48 8b 50 10 48 85 d2 75 e3 48 83 c4 08 5b 41 5c
RSP: 0018:ffff8881d930ebc8 EFLAGS: 00010203
RAX: 5741e5894855dfff RBX: dffffc0000000000 RCX: ffffffff81f8d010
RDX: 0ae83cb1290abc01 RSI: ffffffff81f8cee0 RDI: 5741e5894855e00f
RBP: ffff8881d930ebf0 R08: ffff8881d92fc480 R09: fffffbfff0fab697
R10: fffffbfff0fab697 R11: ffffffff87d5b4bf R12: ffffffff87d5b4f0
R13: fc0000000000ba48 R14: dffffc0000000000 R15: 0000000000000004
FS: 0000000000000000(0000) GS:ffff8881dae00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffff600400 CR3: 00000001d2e72000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with
syzbot.

[Dmitry Vyukov]

On Mon, Dec 31, 2018 at 8:14 AM syzbot
<syzbot+563bb8...@syzkaller.appspotmail.com> wrote:
>
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit: edeca3a769ad Merge tag 'sound-4.20-rc4' of git://git.kerne..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=13316f7b400000
> kernel config: https://syzkaller.appspot.com/x/.config?x=73e2bc0cb6463446
> dashboard link: https://syzkaller.appspot.com/bug?extid=563bb80fa8765090bf16
> compiler: gcc (GCC) 8.0.1 20180413 (experimental)
>
> Unfortunately, I don't have any reproducer for this crash yet.
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+563bb8...@syzkaller.appspotmail.com

Since this involves OOMs and looks like a one-off induced memory corruption:

#syz dup: kernel panic: corrupted stack end in wb_workfn

> --
> You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group.
> To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-bug...@googlegroups.com.
> To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/0000000000006069e7057e4c2833%40google.com.
> For more options, visit https://groups.google.com/d/optout.