missing dbgsym package

Which package are you looking for?

There is the package
linux-image-unsigned-5.11.0-25-generic-dbgsym_5.11.0-25.27_amd64.ddeb
available in
http://ddebs.ubuntu.com/pool/main/l/linux/
see
http://ddebs.ubuntu.com/pool/main/l/linux/linux-image-unsigned-5.11.0-25-generic-dbgsym_5.11.0-25.27_amd64.ddeb

Or are you looking for packages for HWE kernels on older Ubuntu releases?

Yes, I'm looking for HWE kernel on Ubuntu 20.04. Package "linux-image-unsigned-5.11.0-25-generic-dbgsym" is missing from "http://ddebs.ubuntu.com/dists/focal-updates/main/binary-amd64/Packages"

If you want to debug the 5.11.0-* kernel, then you should do this in the Ubuntu release where this is the default kernel, i.e. Ubuntu 21.04 hirsute..

Thanks for the answer. But I want to run `perf' on a production system, which cannot be upgraded to the new release now, to debug a performance issue.

And this workflow only breaks when the system is automatically upgraded from 5.8.0 to 5.11.0. We have "linux-image-unsigned-5.8.0-63-generic-dbgsym" for focal, which is also an HWE kernel. So why not do the same for 5.11.0 kernels?

Also, on focal, we have "linux-image-5.11.0-25-generic-dbgsym", which depends on the unsigned one, but the latter does not exist. This seems to indicate something is broken.

Thanks Manfred Hampl, that solved my question.

@胡玮文 (huww98) ,Hi
May I ask how you solved the problem? I encountered the same problem on 20.04, when I used crash tool, I was prompted that the VMCore version and DBG version did not match, but actually I installed the unsigned version

Although I don't know what is the issue that you have, I have not resolved my issue yet. Ubuntu did not publish debug symbols for 5.11 kernels. It seems we need to wait for 5.13.