[syzbot] upstream boot error: KMSAN: uninit-value in unregister_blkdev

[syzbot <syzbot+a66467b3864e82f8559f@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    16a8829130ca nfs: fix another case of NULL/IS_ERR confusio..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17c0674c280000
kernel config:  https://syzkaller.appspot.com/x/.config?x=a7a1059074b7bdce
dashboard link: https://syzkaller.appspot.com/bug?extid=a66467b3864e82f8559f
compiler:       Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d4c6da24829a/disk-16a88291.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7b2a0fc666c9/vmlinux-16a88291.xz
kernel image: https://storage.googleapis.com/syzbot-assets/710105c78106/bzImage-16a88291.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a66467b3864e82f8559f@syzkaller.appspotmail.com

floppy0: no floppy controllers found
work still pending
=====================================================
BUG: KMSAN: uninit-value in strcmp+0xcf/0x120 lib/string.c:283
 strcmp+0xcf/0x120 lib/string.c:283
 unregister_blkdev+0x142/0x270 block/genhd.c:293
 do_floppy_init+0x4d3/0x15f0 drivers/block/floppy.c:4751
 floppy_async_init+0x17/0x20 drivers/block/floppy.c:4767
 async_run_entry_fn+0x97/0x420 kernel/async.c:127
 process_one_work+0xb0d/0x1410 kernel/workqueue.c:2405
 worker_thread+0x107e/0x1d60 kernel/workqueue.c:2552
 kthread+0x3e8/0x540 kernel/kthread.c:379
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308

Uninit was created at:
 slab_post_alloc_hook+0x12d/0xb60 mm/slab.h:716
 slab_alloc_node mm/slub.c:3451 [inline]
 __kmem_cache_alloc_node+0x4ff/0x8b0 mm/slub.c:3490
 kmalloc_trace+0x51/0x200 mm/slab_common.c:1057
 kmalloc include/linux/slab.h:559 [inline]
 __register_blkdev+0x1a9/0x650 block/genhd.c:246
 do_floppy_init+0x420/0x15f0 drivers/block/floppy.c:4604
 floppy_async_init+0x17/0x20 drivers/block/floppy.c:4767
 async_run_entry_fn+0x97/0x420 kernel/async.c:127
 process_one_work+0xb0d/0x1410 kernel/workqueue.c:2405
 worker_thread+0x107e/0x1d60 kernel/workqueue.c:2552
 kthread+0x3e8/0x540 kernel/kthread.c:379
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308

CPU: 1 PID: 39 Comm: kworker/u4:3 Not tainted 6.4.0-rc1-syzkaller-00012-g16a8829130ca #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023
Workqueue: events_unbound async_run_entry_fn

=====================================================


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