WARNING in kernfs_get

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 0116eb10 ANDROID: arm64: lse: fix LSE atomics with LTO
git tree: android-4.14
console output: https://syzkaller.appspot.com/x/log.txt?x=128e4d0f400000
kernel config: https://syzkaller.appspot.com/x/.config?x=5a0d66ca5b6245f9
dashboard link: https://syzkaller.appspot.com/bug?extid=4406a7377361360004fb
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+4406a7...@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 1 PID: 14340 at fs/kernfs/dir.c:494 kernfs_get+0x52/0x60
fs/kernfs/dir.c:494
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 14340 Comm: syz-executor5 Not tainted 4.14.98+ #6
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0xb9/0x10e lib/dump_stack.c:53
panic+0x1d9/0x3c2 kernel/panic.c:182
__warn.cold+0x2f/0x3b kernel/panic.c:546
ip6_tunnel: ip6tnl1 xmit: Local address not yet configured!
Kernel Offset: 0x5c00000 from 0xffffffff81000000 (relocation range:
0xffffffff80000000-0xffffffffbfffffff)
Rebooting in 86400 seconds..


---
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]

syzbot has found a reproducer for the following crash on:

HEAD commit: b9cd593b Merge 4.14.137 into android-4.14
git tree: android-4.14
console output: https://syzkaller.appspot.com/x/log.txt?x=14ec54c2600000
kernel config: https://syzkaller.appspot.com/x/.config?x=b6fa670e60df3a36

dashboard link: https://syzkaller.appspot.com/bug?extid=4406a7377361360004fb
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14390ece600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+4406a7...@syzkaller.appspotmail.com

input: syz1 as /devices/virtual/input/input2531
input: syz1 as /devices/virtual/input/input2532
input: syz1 as /devices/virtual/input/input2536
input: syz1 as /devices/virtual/input/input2538
------------[ cut here ]------------
WARNING: CPU: 0 PID: 9379 at fs/kernfs/dir.c:494
kernfs_get.part.0+0x5e/0x70 fs/kernfs/dir.c:494

Kernel panic - not syncing: panic_on_warn set ...

input: syz1 as /devices/virtual/input/input2542
CPU: 0 PID: 9379 Comm: syz-executor.5 Not tainted 4.14.137+ #29

Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]

dump_stack+0xca/0x134 lib/dump_stack.c:53
panic+0x1ea/0x3d3 kernel/panic.c:182
__warn.cold+0x2f/0x3a kernel/panic.c:546
report_bug+0x20a/0x248 lib/bug.c:186
fixup_bug arch/x86/kernel/traps.c:177 [inline]
fixup_bug arch/x86/kernel/traps.c:172 [inline]
do_error_trap+0x1bf/0x2d0 arch/x86/kernel/traps.c:295
invalid_op+0x18/0x40 arch/x86/entry/entry_64.S:963
RIP: 0010:kernfs_get.part.0+0x5e/0x70 fs/kernfs/dir.c:494
RSP: 0018:ffff8881d1a178d0 EFLAGS: 00010297
RAX: ffff8881c5b12f00 RBX: ffff8881c8c34a80 RCX: ffffffffa8cdc126
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff8881c8c34a80
RBP: ffff8881ca9fc8c0 R08: 0000000000000001 R09: ffffed1039186951
R10: ffffed1039186950 R11: ffff8881c8c34a83 R12: ffff8881c7ed6d20
R13: 00000000000041ed R14: 0000000000000001 R15: ffff8881c2db7168
kernfs_get fs/kernfs/dir.c:493 [inline]
kernfs_new_node+0x9a/0xf0 fs/kernfs/dir.c:680
kernfs_create_dir_ns+0x3c/0x130 fs/kernfs/dir.c:999
sysfs_create_dir_ns+0xb7/0x1d0 fs/sysfs/dir.c:55
create_dir lib/kobject.c:71 [inline]
kobject_add_internal+0x27f/0x830 lib/kobject.c:229
kobject_add_varg lib/kobject.c:364 [inline]
kobject_add+0x135/0x1a0 lib/kobject.c:409
device_add+0x333/0x13a0 drivers/base/core.c:1809
input_register_device+0x605/0xb20 drivers/input/input.c:2144
uinput_create_device drivers/input/misc/uinput.c:324 [inline]
uinput_ioctl_handler.isra.0+0xa2a/0x1850 drivers/input/misc/uinput.c:839
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:500 [inline]
do_vfs_ioctl+0xabe/0x1040 fs/ioctl.c:684
SYSC_ioctl fs/ioctl.c:701 [inline]
SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x459829
RSP: 002b:00007fa48f5f7c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 0000000000459829
RDX: 0000000000000000 RSI: 0000000000005501 RDI: 0000000000000003
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fa48f5f86d4
R13: 00000000004c4582 R14: 00000000004d87a8 R15: 00000000ffffffff
Kernel Offset: 0x27600000 from 0xffffffff81000000 (relocation range: