WARNING in kernfs

WARNING in kernfs_get
Status: upstream: reported C repro on 2019/04/21 18:18
Reported-by: syzbot+5c4d1ce9497564ba35da@syzkaller.appspotmail.com
First crash: 182d, last: 62d

similar bugs (3):
Kernel	Title	Repro	Count	Last	Reported	Patched	Status
linux-4.19	WARNING in kernfs_get	C	14	38d	177d	0/1	upstream: reported C repro on 2019/04/26 00:08
upstream	WARNING in kernfs_get	C	316	76d	405d	0/14	upstream: reported C repro on 2018/09/10 07:31
android-414	WARNING in kernfs_get	syz	69	40d	193d	0/1	public: reported syz repro on 2019/04/10 15:44

Sample crash report:

------------[ cut here ]------------
WARNING: CPU: 1 PID: 7553 at fs/kernfs/dir.c:494 kernfs_get+0x58/0x70 fs/kernfs/dir.c:494
kobject: 'bluetooth' (ffff888096cc3f00): kobject_add_internal: parent: 'virtual', set: '(null)'
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 7553 Comm: syz-executor608 Not tainted 4.14.113 #3
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x138/0x19c lib/dump_stack.c:53
 panic+0x1f2/0x438 kernel/panic.c:182
 __warn.cold+0x2f/0x34 kernel/panic.c:546
kobject: 'hci3' (ffff88809333e9e8): kobject_add_internal: parent: 'bluetooth', set: 'devices'
 report_bug+0x216/0x254 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+0x1bb/0x310 arch/x86/kernel/traps.c:295
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:314
kobject: 'hci3' (ffff88809333e9e8): kobject_uevent_env
 invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:944
kobject: 'hci4' (ffff888091136a28): kobject_add_internal: parent: 'bluetooth', set: 'devices'
RIP: 0010:kernfs_get+0x58/0x70 fs/kernfs/dir.c:494
kobject: 'hci4' (ffff888091136a28): kobject_uevent_env
RSP: 0018:ffff88809326f978 EFLAGS: 00010297
RAX: ffff888080296040 RBX: ffff88808635d1c0 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000002 RDI: ffff88808635d1c0
RBP: ffff88809326f980 R08: ffff888080296040 R09: 0000000000000001
R10: 0000000000000000 R11: ffff888080296040 R12: ffff88809f440e00
R13: ffff88808e2fbe00 R14: 0000000000000001 R15: 00000000000041ed
 kernfs_new_node+0x95/0xf0 fs/kernfs/dir.c:681
 kernfs_create_dir_ns+0x41/0x140 fs/kernfs/dir.c:1000
 sysfs_create_dir_ns+0xbe/0x1d0 fs/sysfs/dir.c:55
kobject: 'hci2' (ffff8880930729a8): kobject_add_internal: parent: 'bluetooth', set: 'devices'
 create_dir lib/kobject.c:71 [inline]
 kobject_add_internal.part.0.cold+0x114/0x5b1 lib/kobject.c:229
 kobject_add_internal lib/kobject.c:205 [inline]
 kobject_add_varg lib/kobject.c:364 [inline]
 kobject_add+0x11f/0x180 lib/kobject.c:409
 device_add+0x383/0x1490 drivers/base/core.c:1809
 hci_register_dev+0x2d9/0x810 net/bluetooth/hci_core.c:3118
 __vhci_create_device+0x2a6/0x560 drivers/bluetooth/hci_vhci.c:139
 vhci_create_device drivers/bluetooth/hci_vhci.c:163 [inline]
 vhci_get_user drivers/bluetooth/hci_vhci.c:219 [inline]
 vhci_write+0x2a1/0x437 drivers/bluetooth/hci_vhci.c:299
kobject: 'hci4' (ffff888091136a28): fill_kobj_path: path = '/devices/virtual/bluetooth/hci4'
 call_write_iter include/linux/fs.h:1774 [inline]
 new_sync_write fs/read_write.c:469 [inline]
 __vfs_write+0x4ae/0x6c0 fs/read_write.c:482
kobject: 'hci3' (ffff88809333e9e8): fill_kobj_path: path = '/devices/virtual/bluetooth/hci3'
 vfs_write+0x198/0x500 fs/read_write.c:544
 SYSC_write fs/read_write.c:589 [inline]
 SyS_write+0xb8/0x180 fs/read_write.c:581
 do_syscall_64+0x1eb/0x630 arch/x86/entry/common.c:289
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
kobject: 'rfkill632' (ffff8880a14b72e8): kobject_add_internal: parent: 'hci3', set: 'devices'
RIP: 0033:0x441269
RSP: 002b:00007ffc3027d248 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
kobject: 'hci2' (ffff8880930729a8): kobject_uevent_env
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441269
RDX: 0000000000000002 RSI: 00000000200000c0 RDI: 0000000000000003
RBP: 00000000000136d2 R08: 00000000004002c8 R09: 00000000004002c8
R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000401fe0
R13: 0000000000402070 R14: 0000000000000000 R15: 0000000000000000
Kernel Offset: disabled
Rebooting in 86400 seconds..

Crashes (17):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	Maintainers
ci2-linux-4-14	2019/04/21 17:17	linux-4.14.y	68d7a45e	b0e8efcb	.config	log	report	syz	C	gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, tj@kernel.org
ci2-linux-4-14	2019/07/04 07:23	linux-4.14.y	e3c1b273	55565fa0	.config	log	report	syz	C	gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, tj@kernel.org
ci2-linux-4-14	2019/07/04 06:19	linux-4.14.y	e3c1b273	55565fa0	.config	log	report	syz	C	gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, tj@kernel.org
ci2-linux-4-14	2019/07/01 10:05	linux-4.14.y	f4cc0ed9	699d6448	.config	log	report	syz	C	gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, tj@kernel.org
ci2-linux-4-14	2019/06/30 23:43	linux-4.14.y	f4cc0ed9	699d6448	.config	log	report	syz	C	gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, tj@kernel.org
ci2-linux-4-14	2019/06/16 03:33	linux-4.14.y	a74d0e93	442206d7	.config	log	report	syz	C	gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, tj@kernel.org
ci2-linux-4-14	2019/06/15 05:49	linux-4.14.y	2bf3258a	442206d7	.config	log	report	syz	C	gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, tj@kernel.org
ci2-linux-4-14	2019/06/11 02:59	linux-4.14.y	e6a95d88	0159583c	.config	log	report	syz	C	gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, tj@kernel.org
ci2-linux-4-14	2019/04/29 20:51	linux-4.14.y	fa5941f4	b617407b	.config	log	report	syz	C	gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, tj@kernel.org
ci2-linux-4-14	2019/04/27 03:37	linux-4.14.y	68d7a45e	b617407b	.config	log	report	syz	C	gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, tj@kernel.org
ci2-linux-4-14	2019/06/15 13:30	linux-4.14.y	a74d0e93	442206d7	.config	log	report	syz		gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, tj@kernel.org
ci2-linux-4-14	2019/08/19 13:58	linux-4.14.y	45f092f9	b8ceabfc	.config	log	report			gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, tj@kernel.org
ci2-linux-4-14	2019/07/26 21:59	linux-4.14.y	ff33472c	8fe30d3e	.config	log	report			gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, tj@kernel.org
ci2-linux-4-14	2019/07/19 16:15	linux-4.14.y	aea8526e	8304907d	.config	log	report			gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, tj@kernel.org
ci2-linux-4-14	2019/07/01 16:33	linux-4.14.y	f4cc0ed9	907bf746	.config	log	report			gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, tj@kernel.org
ci2-linux-4-14	2019/07/01 10:29	linux-4.14.y	f4cc0ed9	699d6448	.config	log	report			gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, tj@kernel.org
ci2-linux-4-14	2019/06/15 09:09	linux-4.14.y	2bf3258a	442206d7	.config	log	report			gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, tj@kernel.org