Re: [RFC PATCH 6.1.y 0/2] bpf: backport scalar not-equal tracking fixes

[Shung-Hsi Yu]

On Tue, Jun 02, 2026 at 01:47:01PM +0800, Shung-Hsi Yu wrote:
...
> On Tue, Jun 02, 2026 at 02:03:58AM +0800, Zhenzhong Wu wrote:
> > Hi BPF maintainers,
> > 
> > This RFC backports two BPF verifier scalar range-tracking fixes to 6.1.y.
> > The series is intended to fix a verifier state-pruning issue where an
> > impossible scalar path can be kept while the real success path is pruned.
> > 
> > This is a verifier scalar range-tracking issue, not a helper-specific
> > issue.
> > The visible failure is that the verifier can prune the real success
> > continuation, which should not be skipped, and keep only an impossible one.
> ...
> 
> This sounds somewhat similar to the issue fixed in "backport of iterator
> and callback handling fixes" for stable 6.6[1] by @Eduard. Could you try
> to test on the latest stable 6.6.y as well at see if you can reproduce
> the issue there?
...

My mistake, the reproducer you had doesn't use iterator or callback, so
probably not fixed in stable 6.6. I'll take a better look at this later
this week.

> 1: https://lore.kernel.org/stable/20240125001554.25287-1-eddyz87@xxxxxxxxx/
> 2: https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html