Bug caused by 53965c79c2db (USB: Fix device driver race)

[Pany <pany@fedoraproject.org>]

Hi,

I installed fedora 32 into an SD card, with which I booted my Macbook.
It had worked well before, until I upgraded the kernel from 5.8.5 to
5.8.6 [1].

With kernel-5.8.6-200.fc32.x86_64.rpm [2] installed, the boot process
would be stuck at "A start job is running for
/dev/mapper/fedora_localhost_--live-home (<time> / no limit)" (See the
photo of screen [3]).

By appending "systemd.debug-shell=1" to the kernel cmdline, I saved
the journal [4].

This issue has been bisected to commit
53965c79c2dbdc898ffc7fdbab37e920594f5e14 ("USB: Fix device driver
race")

If I revert this commit, the kernel 5.8.6 would boot successfully.

Some background:
- The SDXC card slot on my Macbook Pro [5] is managed by USB controller [6]
- About the SD Card Reader, "lsusb -vv" shows:
```
Bus 002 Device 002: ID 05ac:8406 Apple, Inc. Internal Memory Card Reader
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               3.00
  bDeviceClass            0
  bDeviceSubClass         0
  bDeviceProtocol         0
  bMaxPacketSize0         9
  idVendor           0x05ac Apple, Inc.
  idProduct          0x8406 Internal Memory Card Reader
  bcdDevice            8.20
  iManufacturer           3 Apple
  iProduct                4 Card Reader
  iSerial                 5 000000000820
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength       0x002c
    bNumInterfaces          1
    bConfigurationValue     1
    iConfiguration          0
    bmAttributes         0xa0
      (Bus Powered)
      Remote Wakeup
    MaxPower              896mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           2
      bInterfaceClass         8 Mass Storage
      bInterfaceSubClass      6 SCSI
      bInterfaceProtocol     80 Bulk-Only
      iInterface              0
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0400  1x 1024 bytes
        bInterval               0
        bMaxBurst               4
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x02  EP 2 OUT
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0400  1x 1024 bytes
        bInterval               0
        bMaxBurst               4
Binary Object Store Descriptor:
  bLength                 5
  bDescriptorType        15
  wTotalLength       0x0016
  bNumDeviceCaps          2
  USB 2.0 Extension Device Capability:
    bLength                 7
    bDescriptorType        16
    bDevCapabilityType      2
    bmAttributes   0x00000002
      HIRD Link Power Management (LPM) Supported
  SuperSpeed USB Device Capability:
    bLength                10
    bDescriptorType        16
    bDevCapabilityType      3
    bmAttributes         0x02
      Latency Tolerance Messages (LTM) Supported
    wSpeedsSupported   0x000e
      Device can operate at Full Speed (12Mbps)
      Device can operate at High Speed (480Mbps)
      Device can operate at SuperSpeed (5Gbps)
    bFunctionalitySupport   1
      Lowest fully-functional device speed is Full Speed (12Mbps)
    bU1DevExitLat          10 micro seconds
    bU2DevExitLat        2047 micro seconds
can't get debug descriptor: Resource temporarily unavailable
Device Status:     0x001c
  (Bus Powered)
  U1 Enabled
  U2 Enabled
  Latency Tolerance Messaging (LTM) Enabled
```

I'm looking forward to getting help from you guys. Thanks!

[1] https://bugzilla.redhat.com/show_bug.cgi?id=1878347
[2] https://koji.fedoraproject.org/koji/buildinfo?buildID=1605304
[3] https://bugzilla.redhat.com/attachment.cgi?id=1714633
[4] https://bugzilla.redhat.com/attachment.cgi?id=1717469
[5] https://support.apple.com/kb/SP715?locale=en_US
[6] https://support.apple.com/en-us/HT204384#4
-- 
Regards,
Pany
pany@fedoraproject.org