Re: [PATCH 6.12 000/307] 6.12.93-rc1 review

[Jamal Hadi Salim]

On Mon, Jun 8, 2026 at 6:08 AM Miguel Ojeda
<miguel.ojeda.sandonis@xxxxxxxxx> wrote:
>
> On Mon, Jun 8, 2026 at 11:55 AM Jamal Hadi Salim <jhs@xxxxxxxxxxxx> wrote:
> >
> > Thanks for reporting this.
>
> You're welcome!
>
> > Unless i am looking at the wrong code version, in the current code i
> > see m_eaction is always initialized before being used.
> > m_eaction = READ_ONCE(m->tcfm_eaction);
> > Probably a compiler false positive?
>
> No, it is an actual bug -- you have:
>
>     int i, m_eaction;
>     ...
>     is_redirect = tcf_mirred_is_act_redirect(m_eaction);
>     ...
>     m_eaction = READ_ONCE(m->tcfm_eaction);
>
> i.e. the assignment goes later.
>
> Maybe you are looking at mainline? Please note that this is a 6.12.y
> -rc thread -- are you looking at the commit hash I mentioned?
>
> Or maybe you are looking at `tcf_blockcast()` instead of `tcf_mirred_act()`?
>

I was certainly looking at the wrong version.
For example what you described as commit a01fbdecc3a2 ("net/sched:
act_mirred: Fix return code in early mirred redirect error paths")
shows up for me as commit e80ad525fc7e

I believe this bug slipped in during a small window but was fixed very
quickly. Probably some fix never trickled to stable.
If you can point me to the exact tree where this happens i can take a look.
Still curious: So only the arm compiler catches this?

cheers,
jamal