Re: [PATCH v2] mm/page_isolation: fix a deadlock with printk()

Qian Cai
2019-10-10T09:01:51Z

> On Oct 9, 2019, at 12:23 PM, Michal Hocko <mhocko@kernel.org> wrote:
>
> If this was only about the memory offline code then I would agree. But
> we are talking about any printk from the zone->lock context and that is
> a bigger deal. Besides that it is quite natural that the printk code
> should be more universal and allow to be also called from the MM
> contexts as much as possible. If there is any really strong reason this
> is not possible then it should be documented at least.

Where is the best place to document this? I am thinking about under the “struct zone” definition’s lock field in mmzone.h.

Does workaround this potential deadlock and fix a few lockdep false positives for free count as a really strong reason?