Re: [PATCH v4 2/6] xen: do not merge reserved pages in free_heap_pages()

[Julien Grall <julien@xxxxxxx>]

Hi Penny,

On 10/05/2022 03:27, Penny Zheng wrote:
> The code in free_heap_pages() will try to merge pages with the
> successor/predecessor if pages are suitably aligned. So if the pages
> reserved are right next to the pages given to the heap allocator,
> free_heap_pages() will merge them, and give the reserved pages to heap
> allocator accidently as a result.
>
> So in order to avoid the above scenario, this commit updates free_heap_pages()
> to check whether the predecessor and/or successor has PGC_reserved set,
> when trying to merge the about-to-be-freed chunk with the predecessor
> and/or successor.
>
> Signed-off-by: Penny Zheng <penny.zheng@xxxxxxx>
> Suggested-by: Julien Grall <jgrall@xxxxxxxxxx>
NIT: In general, the tags are historically ordered. I.e I first sugested 
and then you wrote the patch. So the two tags should be inverted.
This can be done on commit:

Reviewed-by: Julien Grall <jgrall@xxxxxxxxxx>

Cheers,

--
Julien Grall