[Kernel] Nuvoton NPCM7xx unbind FIU issue

[Joel Stanley]

On Wed, 28 Apr 2021 at 01:15, George Hung (洪忠敬)
<George.Hung at quantatw.com> wrote:
>
> Hi Joel,
>
> For kernel v5.x, we found that when we unbind FIU module at the first time, it would cause kernel warning like that:
>
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 2174 at lib/refcount.c:190 refcount_sub_and_test_checked+0x60/0xbc
> refcount_t: underflow; use-after-free.
> Modules linked in:
> CPU: 0 PID: 2174 Comm: gbs-sysinit.sh Not tainted 5.4.80-ebad8cd-dirty-c46444d #1 Hardware name: NPCM7XX Chip family

Hopefully you're not using 5.4.80 anywhere :)

>
> And there's a fix on kernel github for now: https://github.com/torvalds/linux/commit/794aaf01444d4e765e2b067cba01cc69c1c68ed9
>
> Could you help to pull this fix to current OpenBMC kernel repo. to fix this issue ?

Sure. I've applied this change to dev-5.10.

I imagine it will show up in the stable tree shortly too, so if you
are really using v5.4 I recommend merging in the latest stable tree
when that happens.

Cheers,

Joel