Re: [PATCH AUTOSEL 3.18 8/9] mm/vmstat.c: assert that vmstat_text is in sync with stat_items_size

Andrew Morton
2018-11-15T22:08:14Z

On Tue, 13 Nov 2018 00:52:51 -0500 Sasha Levin <sashal@kernel.org> wrote:

> From: Jann Horn <jannh@google.com>
>
> [ Upstream commit f0ecf25a093fc0589f0a6bc4c1ea068bbb67d220 ]
>
> Having two gigantic arrays that must manually be kept in sync, including
> ifdefs, isn't exactly robust. To make it easier to catch such issues in
> the future, add a BUILD_BUG_ON().
>
> ...
>
> --- a/mm/vmstat.c
> +++ b/mm/vmstat.c
> @@ -1189,6 +1189,8 @@ static void *vmstat_start(struct seq_file *m, loff_t *pos)
> stat_items_size += sizeof(struct vm_event_state);
> #endif
>
> + BUILD_BUG_ON(stat_items_size !=
> + ARRAY_SIZE(vmstat_text) * sizeof(unsigned long));
> v = kmalloc(stat_items_size, GFP_KERNEL);
> m->private = v;
> if (!v)

I don't think there's any way in which this can make a -stable kernel
more stable!

Generally, I consider -stable in every patch I merge, so for each patch
which doesn't have cc:stable, that tag is missing for a reason.

In other words, your criteria for -stable addition are different from
mine.

And I think your criteria differ from those described in
Documentation/process/stable-kernel-rules.rst.

So... what is your overall thinking on patch selection?