general protection fault in rb_erase (3)

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 9e50b94b Add linux-next specific files for 20200703
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=14a5cbcb100000
kernel config: https://syzkaller.appspot.com/x/.config?x=f99cc0faa1476ed6
dashboard link: https://syzkaller.appspot.com/bug?extid=ffc5097bd34e69106658
compiler: gcc (GCC) 10.1.0-syz 20200507

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+ffc509...@syzkaller.appspotmail.com

device veth1_macvtap left promiscuous mode
device veth0_macvtap left promiscuous mode
device veth1_vlan left promiscuous mode
device veth0_vlan left promiscuous mode
general protection fault, probably for non-canonical address 0xdffffc0000000002: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017]
CPU: 0 PID: 2809 Comm: kworker/u4:2 Not tainted 5.8.0-rc3-next-20200703-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net
RIP: 0010:__rb_erase_augmented include/linux/rbtree_augmented.h:266 [inline]
RIP: 0010:rb_erase+0xb7/0x1210 lib/rbtree.c:443
Code: 5e 10 4c 89 f5 48 ba 00 00 00 00 00 fc ff df 48 85 db 75 0b e9 9f 04 00 00 48 89 dd 48 89 c3 4c 8d 63 10 4c 89 e0 48 c1 e8 03 <80> 3c 10 00 0f 85 f3 0b 00 00 48 8b 43 10 48 85 c0 75 dc 48 8d 7b
RSP: 0018:ffffc90017aff6c8 EFLAGS: 00010202
RAX: 0000000000000002 RBX: 0000000000000001 RCX: 1ffff11000022949
RDX: dffffc0000000000 RSI: ffff888000114e08 RDI: ffff888000114a48
RBP: ffff888000110000 R08: 0000000000000000 R09: ffffffff89cdc267
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000011
R13: ffff888000114c08 R14: ffff888000114a38 R15: ffff888000114e08
FS: 0000000000000000(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000caa008 CR3: 00000000a7aa1000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
kernfs_unlink_sibling fs/kernfs/dir.c:398 [inline]
__kernfs_remove+0x623/0xa30 fs/kernfs/dir.c:1331
kernfs_remove_by_name_ns+0x51/0xb0 fs/kernfs/dir.c:1516
kernfs_remove_by_name include/linux/kernfs.h:593 [inline]
remove_files+0x96/0x1c0 fs/sysfs/group.c:28
sysfs_remove_group+0x87/0x170 fs/sysfs/group.c:289
sysfs_remove_groups fs/sysfs/group.c:313 [inline]
sysfs_remove_groups+0x5c/0xa0 fs/sysfs/group.c:305
device_remove_groups drivers/base/core.c:1790 [inline]
device_remove_attrs+0xa9/0x150 drivers/base/core.c:1972
device_del+0x474/0xd20 drivers/base/core.c:2856
rollback_registered_many+0xa07/0xf60 net/core/dev.c:9004
unregister_netdevice_many.part.0+0x1a/0x2f0 net/core/dev.c:10122
unregister_netdevice_many net/core/dev.c:10121 [inline]
default_device_exit_batch+0x30c/0x3d0 net/core/dev.c:10605
ops_exit_list+0x10d/0x160 net/core/net_namespace.c:189
cleanup_net+0x4ea/0xa00 net/core/net_namespace.c:603
process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
kthread+0x3b5/0x4a0 kernel/kthread.c:292
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
Modules linked in:
---[ end trace 85e16a2eaea866a0 ]---
RIP: 0010:__rb_erase_augmented include/linux/rbtree_augmented.h:266 [inline]
RIP: 0010:rb_erase+0xb7/0x1210 lib/rbtree.c:443
Code: 5e 10 4c 89 f5 48 ba 00 00 00 00 00 fc ff df 48 85 db 75 0b e9 9f 04 00 00 48 89 dd 48 89 c3 4c 8d 63 10 4c 89 e0 48 c1 e8 03 <80> 3c 10 00 0f 85 f3 0b 00 00 48 8b 43 10 48 85 c0 75 dc 48 8d 7b
RSP: 0018:ffffc90017aff6c8 EFLAGS: 00010202
RAX: 0000000000000002 RBX: 0000000000000001 RCX: 1ffff11000022949
RDX: dffffc0000000000 RSI: ffff888000114e08 RDI: ffff888000114a48
RBP: ffff888000110000 R08: 0000000000000000 R09: ffffffff89cdc267
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000011
R13: ffff888000114c08 R14: ffff888000114a38 R15: ffff888000114e08
FS: 0000000000000000(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000caa008 CR3: 00000000a2764000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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[syzbot]

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