[syzbot] [raid?] WARNING: kobject bug in bind_rdev_to_array

[syzbot <syzbot+95eeb4ada2349a2170ea@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    518e5b794c06 Merge tag 'for-7.3-rc3-tag' of git://git.kern..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12345ff9580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=c3bddd52b22c2498
dashboard link: https://syzkaller.appspot.com/bug?extid=95eeb4ada2349a2170ea
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-518e5b79.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/5307a29f916b/vmlinux-518e5b79.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7d4c698a99b1/bzImage-518e5b79.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+95eeb4ada2349a2170ea@syzkaller.appspotmail.com

------------[ cut here ]------------
kobject: '(null)' (ffff8880120640f0): is not initialized, yet kobject_get() is being called.
WARNING: lib/kobject.c:642 at kobject_get lib/kobject.c:640 [inline], CPU#0: syz.0.0/5330
WARNING: lib/kobject.c:642 at kobject_add_internal+0xea/0xcd0 lib/kobject.c:225, CPU#0: syz.0.0/5330
Modules linked in:
CPU: 0 UID: 0 PID: 5330 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:kobject_get lib/kobject.c:640 [inline]
RIP: 0010:kobject_add_internal+0x113/0xcd0 lib/kobject.c:225
Code: 04 4c 89 e0 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 74 08 4c 89 e7 e8 57 11 5b f6 49 8b 34 24 4c 89 f7 4c 89 e2 <67> 48 0f b9 3a e9 e4 00 00 00 e8 fe 6a e9 f5 b8 fe ff ff ff e9 fb
RSP: 0018:ffffc9000f1f78a8 EFLAGS: 00010246
RAX: 1ffff1100240c81e RBX: ffff888052836080 RCX: dffffc0000000000
RDX: ffff8880120640f0 RSI: 0000000000000000 RDI: ffffffff908d7cc0
RBP: 0000000000000000 R08: ffff888000b14b00 R09: 0000000000000008
R10: 0000000000000007 R11: 0000000000000002 R12: ffff8880120640f0
R13: dffffc0000000000 R14: ffffffff908d7cc0 R15: dffffc0000000000
FS:  00007ffbef2886c0(0000) GS:ffff88808c2c2000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f208abad1bc CR3: 000000000e910000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 kobject_add_varg lib/kobject.c:374 [inline]
 kobject_add+0x163/0x240 lib/kobject.c:426
 bind_rdev_to_array+0x80c/0xdd0 drivers/md/md.c:2621
 md_add_new_disk+0xe3b/0x1850 drivers/md/md.c:7684
 md_ioctl+0x200a/0x2610 drivers/md/md.c:8499
 blkdev_ioctl+0x5e3/0x740 block/ioctl.c:798
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ffbee39e159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffbef287fe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007ffbee626090 RCX: 00007ffbee39e159
RDX: 0000200000000420 RSI: 0000000040140921 RDI: 0000000000000004
RBP: 00007ffbee43506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffbee626128 R14: 00007ffbee626090 R15: 00007ffe703ff368
 </TASK>
----------------
Code disassembly (best guess):
   0:	04 4c                	add    $0x4c,%al
   2:	89 e0                	mov    %esp,%eax
   4:	48 c1 e8 03          	shr    $0x3,%rax
   8:	48 b9 00 00 00 00 00 	movabs $0xdffffc0000000000,%rcx
   f:	fc ff df
  12:	80 3c 08 00          	cmpb   $0x0,(%rax,%rcx,1)
  16:	74 08                	je     0x20
  18:	4c 89 e7             	mov    %r12,%rdi
  1b:	e8 57 11 5b f6       	call   0xf65b1177
  20:	49 8b 34 24          	mov    (%r12),%rsi
  24:	4c 89 f7             	mov    %r14,%rdi
  27:	4c 89 e2             	mov    %r12,%rdx
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	e9 e4 00 00 00       	jmp    0x118
  34:	e8 fe 6a e9 f5       	call   0xf5e96b37
  39:	b8 fe ff ff ff       	mov    $0xfffffffe,%eax
  3e:	e9                   	.byte 0xe9
  3f:	fb                   	sti


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