On Fri, Mar 26, 2021 at 07:57:52AM +0100, Harald Dunkel wrote:

Hi folks,

using

	dd if=ubuntu-20.10-desktop-amd64.iso bs=64k of=/dev/sdx

on 5.11.10 to write a live iso to USB stick dd never returns.

lsof shows that the file handles for source and destination
have been closed, but dd doesn't exit. It cannot be interrupted
or killed, either. If I run "sync" in another terminal, then this
gets stuck as well.

I could reproduce this problem using Debian's 5.10.13-1 and
5.11.{9,10} built from the sources in git, on Debian 10 and
Unstable. I tried to copy the ubuntu live iso and the RHEL 8.3
installer iso. 3 different USB sticks.

There is no such problem using Debian's 4.19.0-16-amd64 kernel
on Debian 10.

Any chance you can see if you can bisect this down to an offending
commit?  The jump from 4.19 to 5.11 is quite big (2 years).

But no, this works for me, just did it yesterday and I run some builds
off of usb storage devices.

thanks,

greg k-h