Re: Bug 220102 - struct taskstats breaks backward compatibility since version 15

[Andrew Morton]

On Fri, 09 May 2025 21:35:59 +0300 Boian Bonev <bbonev@xxxxxxxxxx> wrote:

> Hello!
> 
> Since version 15 (TASKSTATS_VERSION=15) the new layout of the structure
> adds fields in the middle of the structure, rendering all old software
> incompatible with newer kernels and software compiled against the new
> kernel headers incompatible with older kernels.

Yikes.  Yes, we did change the versioning but such an incompatibility
seems undesirable and unnecessarily disruptive.

> I think that change has to be reverted and the added fields moved to
> the end of the structure. Also bumping the version to 16 after the
> change is a good idea in order for the userspace software to be able to
> distinguish the different formats.

Yes, please send along the patch.  Include the suitable Fixes: and we
can backport this into the affected -stable kernels.

> https://bugzilla.kernel.org/show_bug.cgi?id=220102