Re: [PATCH] mm: page_alloc: check the order of compound page event when the order is 0

[Vishal Moola]

On Thu, Oct 12, 2023 at 10:11:06AM +0900, Hyesoo Yu wrote:
> For compound pages, the head sets the PG_head flag and
> the tail sets the compound_head to indicate the head page.
> If a user allocates a compound page and frees it with a different
> order, the compound page information will not be properly
> initialized. To detect this problem, compound_page(page) and
> the order are compared, but it is not checked when the order is 0.
> That error should be checked regardless of the order.

I believe all compound pages are order >= 1, so this error can't occur
when the order is 0.