On Thu, 11 Sep 2025, Ingo Franzki wrote:
> >> So, it looks like a dm-crypt bug.
> >>
> >> Please, revert my patches and run the same test on a clean 6.17.0-rc5 just
> >> to verify that the patches do not introduce the bug.
> >
> > With your patches reverted the combined mode fails the same way as with
> > your patches.
> > So they did not introduce the bug.
>
> Mikulas, do you have any idea what could be causing this errors?
> Is it that dm-crypt is not properly dealing with async-only HMAC ciphers?
> Async-only encryption ciphers seem to work fine in dm-crypt, since LUKS with
> PAES (but no integrity) works fine, and PAES is an async-onky cipher.
> LUKS with sync-HMAC ciphers (e.g. clear key HMAC) also works fine, even in
> combination with PAES.
Yes, I think that it's a problem with async HMAC. The bug is probably
either in dm-crypt or in the crypto library.
Do you have some other (non-dm-crypt-related) workload that uses the
async authentication, so that we can determine whether the bug is in
dm-crypt or crypto?
Otherwise, would it be possible to give us a virtual machine on the
mainframe to debug this issue?
Mikulas
