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

[Jamal Hadi Salim]

Hi Miguel,

Thanks for reporting this.

On Sun, Jun 7, 2026 at 1:32 PM Miguel Ojeda <ojeda@xxxxxxxxxx> wrote:
>
> On Sun, 07 Jun 2026 11:56:37 +0200 Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
> >
> > This is the start of the stable review cycle for the 6.12.93 release.
> > There are 307 patches in this series, all will be posted as a response
> > to this one.  If anyone has any issues with these being applied, please
> > let me know.
> >
> > Responses should be made by Tue, 09 Jun 2026 09:56:47 +0000.
> > Anything received after that time might be too late.
>
> Boot-tested under QEMU for Rust x86_64, arm64 and riscv64; built-tested
> for loongarch64:
>
> Tested-by: Miguel Ojeda <ojeda@xxxxxxxxxx>
>
> arm32 also builds fine.
>
> On arm64, I am seeing:
>
>     net/sched/act_mirred.c:451:43: warning: variable 'm_eaction' is uninitialized when used here [-Wuninitialized]
>       451 |         is_redirect = tcf_mirred_is_act_redirect(m_eaction);
>           |                                                  ^~~~~~~~~
>     net/sched/act_mirred.c:429:18: note: initialize the variable 'm_eaction' to silence this warning
>       429 |         int i, m_eaction;
>           |                         ^
>           |                          = 0
>
> due to commit a01fbdecc3a2 ("net/sched: act_mirred: Fix return code in
> early mirred redirect error paths") here.
>
> And that one seems to be missing at least the assignment to the variable
> that happened in commit a005fa5d7502 ("net/sched: act_mirred: Fix
> blockcast recursion bypass leading to stack overflow").
>

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?
As per suggestion emmited, initializing m_eaction to 0 should help.
Not sure what the process is.
Perhaps, Miguel you want to send the fix? commit should say "appease
compiler ..."

cheers,
jamal


> I hope this helps!
>
> Cc: Kito Xu (veritas501) <hxzene@xxxxxxxxx>
> Cc: Victor Nogueira <victor@xxxxxxxxxxxx>
> Cc: Paolo Abeni <pabeni@xxxxxxxxxx>
> Cc: Jamal Hadi Salim <jhs@xxxxxxxxxxxx>
> Cc: Jiri Pirko <jiri@xxxxxxxxxxx>
> Cc: netdev@xxxxxxxxxxxxxxx
>
> Cheers,
> Miguel