WARNING in __device_add

[upstream] WARNING in __device_add_disk
Status: upstream: reported C repro on 2018/04/19 17:06
Reported-by: syzbot+3337db851ace689ceb50@syzkaller.appspotmail.com
First: 92d, last: 8d00h

Sample crash report:

RAX: ffffffffffffffda RBX: 00000000006dbc24 RCX: 0000000000445989
RDX: 00000000004ae3f9 RSI: 0000000020000880 RDI: 00000000200008c0
RBP: 0000000000000000 R08: 00007f03acf92ca0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 00000000006dbc20
R13: 0000000000000005 R14: 0030656c69662f2e R15: 0000000000000001
WARNING: CPU: 1 PID: 4515 at block/genhd.c:697 __device_add_disk+0x104a/0x1340 block/genhd.c:697
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 4515 Comm: syz-executor745 Not tainted 4.17.0-rc5+ #51
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1b9/0x294 lib/dump_stack.c:113
 panic+0x22f/0x4de kernel/panic.c:184
 __warn.cold.8+0x163/0x1b3 kernel/panic.c:536
 report_bug+0x252/0x2d0 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:178 [inline]
 do_error_trap+0x1de/0x490 arch/x86/kernel/traps.c:296
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:315
 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:992
RIP: 0010:__device_add_disk+0x104a/0x1340 block/genhd.c:697
RSP: 0018:ffff8801d903f4e0 EFLAGS: 00010293
RAX: ffff8801d8ce8600 RBX: ffff8801d8e30200 RCX: ffffffff83438983
RDX: 0000000000000000 RSI: ffffffff83438aba RDI: 0000000000000005
RBP: ffff8801d903f6b0 R08: ffff8801d8ce8600 R09: 0000000000000006
R10: ffff8801d8ce8600 R11: 0000000000000000 R12: 00000000fffffff4
R13: ffff8801d903f688 R14: ffff8801d8e30760 R15: ffff8801d8e30204
 device_add_disk+0x22/0x30 block/genhd.c:717
 add_disk include/linux/genhd.h:399 [inline]
 loop_add+0x70b/0x9c0 drivers/block/loop.c:1895
 loop_probe+0x185/0x1c0 drivers/block/loop.c:1967
 kobj_lookup+0x269/0x460 drivers/base/map.c:124
 get_gendisk+0x4c/0x380 block/genhd.c:825
 bdev_get_gendisk fs/block_dev.c:1063 [inline]
 bd_start_claiming fs/block_dev.c:1118 [inline]
 blkdev_get+0x16a/0xb30 fs/block_dev.c:1604
 blkdev_get_by_path+0x5c/0xe0 fs/block_dev.c:1689
 mount_bdev+0x5d/0x3e0 fs/super.c:1122
 fuse_mount_blk+0x34/0x40 fs/fuse/inode.c:1222
 mount_fs+0xae/0x328 fs/super.c:1267
 vfs_kern_mount.part.34+0xd4/0x4d0 fs/namespace.c:1037
 vfs_kern_mount fs/namespace.c:1027 [inline]
 do_new_mount fs/namespace.c:2518 [inline]
 do_mount+0x564/0x3070 fs/namespace.c:2848
 ksys_mount+0x12d/0x140 fs/namespace.c:3064
 __do_sys_mount fs/namespace.c:3078 [inline]
 __se_sys_mount fs/namespace.c:3075 [inline]
 __x64_sys_mount+0xbe/0x150 fs/namespace.c:3075
 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x445989
RSP: 002b:00007f03acf92c88 EFLAGS: 00000206 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00000000006dbc24 RCX: 0000000000445989
RDX: 00000000004ae3f9 RSI: 0000000020000880 RDI: 00000000200008c0
RBP: 0000000000000000 R08: 00007f03acf92ca0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 00000000006dbc20
R13: 0000000000000005 R14: 0030656c69662f2e R15: 0000000000000001
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..

All crashes (11):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	Maintainers
ci-upstream-kasan-gce-root	2018/05/15 14:17	upstream	67b8d5c7081221efa252e111cd52532ec6d4266f	661fd7b9882caba55e3fbc1c95fd4602ebfe580d	.config	log	report	syz	C	["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-root	2018/05/12 16:12	upstream	f0ab773f5c96c29a5227234c4b5a820f5591b74d	e726f42b64de35f7a8fc316b0eb1169106d8e714	.config	log	report	syz	C	["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-root	2018/04/30 12:36	upstream	6da6c0db5316275015e8cc2959f12a17584aeb64	06db3cec94c54e1cf720cdd5db72761514569d56	.config	log	report	syz	C	["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce	2018/04/19 14:16	upstream	87ef12027b9b1dd0e0b12cf311fbcb19f9d92539	3642839c105d2c84160c10866805f903a22fa343	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-root	2018/07/13 01:57	upstream	63f04777162181798399a2c4e5436d0d0c16291b	06c33b3af0ff4072fb002879f83077c9d162a224	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-root	2018/05/26 12:22	upstream	bc2dbc5420e82560e650f8531ceca597441ca171	f48c20b8f9b2a6c26629f11cc15e1c9c316572c8	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce	2018/05/22 07:23	upstream	a048a07d7f4535baa4cbad6bc024f175317ab938	f48c20b8f9b2a6c26629f11cc15e1c9c316572c8	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-root	2018/05/21 21:43	upstream	6741c4bb389da103c0d79ad1961884628900bfe6	f48c20b8f9b2a6c26629f11cc15e1c9c316572c8	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce	2018/05/12 23:37	upstream	427fbe89261d8f11cd20b5a4ba94e977061f69d6	e726f42b64de35f7a8fc316b0eb1169106d8e714	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/06/05 23:28	upstream	5037be168f0e4ee910602935b1180291082d3aac	863a24bb5da2268d7705ec57fb2d16dfafa2e02c	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-linux-next-kasan-gce-root	2018/07/11 11:11	linux-next	98be45067040799a801e6ce52d8bf4659a153893	2e0e3130f967984ba51ac1387b67040f0d953942	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]