general protection fault in rb_insert_color

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: fdc07232 Linux 4.19.120
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=16f08b38100000
kernel config: https://syzkaller.appspot.com/x/.config?x=7848de5371b4200c
dashboard link: https://syzkaller.appspot.com/bug?extid=1a82b51b179cce2b7a1f
compiler: gcc (GCC) 9.0.0 20181231 (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+1a82b5...@syzkaller.appspotmail.com

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: 1570 Comm: syz-executor.0 Not tainted 4.19.120-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__rb_insert lib/rbtree.c:131 [inline]
RIP: 0010:rb_insert_color+0x6d/0xb60 lib/rbtree.c:452
Code: 48 89 e8 48 c1 e8 03 42 80 3c 28 00 0f 85 e9 06 00 00 48 8b 5d 00 f6 c3 01 0f 85 9b 01 00 00 4c 8d 7b 08 4c 89 f8 48 c1 e8 03 <42> 80 3c 28 00 0f 85 b1 06 00 00 4c 8b 73 08 49 39 ee 0f 84 87 01
RSP: 0018:ffff88804ff97760 EFLAGS: 00010202
RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffc90005b08000
RDX: 1ffff11013d67623 RSI: ffff8880a7479228 RDI: ffff88809eb3b118
RBP: ffff888000106498 R08: ffff888050eb0600 R09: ffffed1014e8f239
R10: ffffed1014e8f238 R11: ffff8880a74791c7 R12: ffff88809eb3b118
R13: dffffc0000000000 R14: ffff88809eb3b0e0 R15: 0000000000000008
FS: 00007fc9e91d4700(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c45d8bf000 CR3: 00000000995e3000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
kernfs_link_sibling+0x2bd/0x420 fs/kernfs/dir.c:369
kernfs_add_one+0x227/0x4d0 fs/kernfs/dir.c:789
kernfs_create_dir_ns+0xf6/0x150 fs/kernfs/dir.c:1029
sysfs_create_dir_ns+0x127/0x280 fs/sysfs/dir.c:58
create_dir lib/kobject.c:88 [inline]
kobject_add_internal+0x29d/0x8c0 lib/kobject.c:247
kobject_add_varg lib/kobject.c:382 [inline]
kobject_add+0x150/0x1c0 lib/kobject.c:426
device_add+0x3a4/0x1660 drivers/base/core.c:2106
netdev_register_kobject+0x180/0x3b0 net/core/net-sysfs.c:1765
register_netdevice+0x7f7/0xf50 net/core/dev.c:8710
register_netdev+0x2d/0x50 net/core/dev.c:8832
sit_init_net+0x37b/0xa50 net/ipv6/sit.c:1867
ops_init+0xaf/0x410 net/core/net_namespace.c:129
setup_net+0x2c2/0x6f0 net/core/net_namespace.c:315
copy_net_ns+0x1d9/0x331 net/core/net_namespace.c:438
create_new_namespaces+0x3fb/0x7c0 kernel/nsproxy.c:107
unshare_nsproxy_namespaces+0xbd/0x1f0 kernel/nsproxy.c:206
ksys_unshare+0x439/0x8d0 kernel/fork.c:2530
__do_sys_unshare kernel/fork.c:2598 [inline]
__se_sys_unshare kernel/fork.c:2596 [inline]
__x64_sys_unshare+0x2d/0x40 kernel/fork.c:2596
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45c829
Code: 0d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fc9e91d3c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 0000000000509cc0 RCX: 000000000045c829
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040000000
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000c46 R14: 00000000004ce72e R15: 00007fc9e91d46d4
Modules linked in:
---[ end trace b5e07c7a40dec7ca ]---
RIP: 0010:__rb_insert lib/rbtree.c:131 [inline]
RIP: 0010:rb_insert_color+0x6d/0xb60 lib/rbtree.c:452
Code: 48 89 e8 48 c1 e8 03 42 80 3c 28 00 0f 85 e9 06 00 00 48 8b 5d 00 f6 c3 01 0f 85 9b 01 00 00 4c 8d 7b 08 4c 89 f8 48 c1 e8 03 <42> 80 3c 28 00 0f 85 b1 06 00 00 4c 8b 73 08 49 39 ee 0f 84 87 01
RSP: 0018:ffff88804ff97760 EFLAGS: 00010202
RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffc90005b08000
RDX: 1ffff11013d67623 RSI: ffff8880a7479228 RDI: ffff88809eb3b118
RBP: ffff888000106498 R08: ffff888050eb0600 R09: ffffed1014e8f239
R10: ffffed1014e8f238 R11: ffff8880a74791c7 R12: ffff88809eb3b118
R13: dffffc0000000000 R14: ffff88809eb3b0e0 R15: 0000000000000008
FS: 00007fc9e91d4700(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000001d5d978 CR3: 00000000995e3000 CR4: 00000000001406e0
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#status for how to communicate with syzbot.

[syzbot]

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