Re: [PATCH v2] driver core: Fix bus_type.match() error handling

[Bart Van Assche <bvanassche@acm.org>]

On 8/19/22 10:45, Isaac Manjarres wrote:
> It seems that the patches mentioned in [1] are causing a hang during
> reboot for various ARM emulations when booting from USB. Can you please
> take a look? There's more information about what defconfig, rootfs, and
> qemu commandline to use at [2].

Unfortunately I can't reproduce this hang in an x86 VM with kernel 
v6.0-rc1 and a USB disk attached via virt-manager. The lsscsi -v output 
shows that a USB disk has been attached:

[9:0:0:0]    disk    QEMU     QEMU HARDDISK    2.5+  /dev/sdd
   dir: /sys/bus/scsi/devices/9:0:0:0 
[/sys/devices/pci0000:00/0000:00:07.0/usb2/2-2/2-2:1.0/host9/target9:0:0/9:0:0:0]

Rebooting that VM happens in the expected time and without triggering 
any kernel warnings.

Since the issue has been observed in qemu, how about sharing the sysrq-t 
output? I recommend to collect that output as follows:
* Send the serial console output to a file. This involves adding 
console=ttyS0,115200n8 to the kernel command line and using the proper 
qemu options to save the serial console output into a file.
* Reproduce the hang and send the sysrq-t key sequence to qemu, e.g. as 
follows: virsh send-key ${vm_name} KEY_LEFTALT KEY_SYSRQ KEY_T

Thanks,

Bart.