Re: [PATCH] mm/cma: fix reserved page leak on activation failure

[Muchun Song <muchun.song@linux.dev>]

> On May 26, 2026, at 19:51, Oscar Salvador (SUSE) <osalvador@kernel.org> wrote:
> 
> On Tue, May 26, 2026 at 04:30:03AM -0700, Usama Arif wrote:
>> On Fri, 22 May 2026 14:26:58 +0800 Muchun Song <songmuchun@bytedance.com> wrote:
> ...
>>> diff --git a/mm/cma.c b/mm/cma.c
>>> index c7ca567f4c5c..a30075507d41 100644
>>> --- a/mm/cma.c
>>> +++ b/mm/cma.c
>>> @@ -188,10 +188,13 @@ static void __init cma_activate_area(struct cma *cma)
>>> 
>>>    /* Expose all pages to the buddy, they are useless for CMA. */
>>>    if (!test_bit(CMA_RESERVE_PAGES_ON_ERROR, &cma->flags)) {
>>> -        for (r = 0; r < allocrange; r++) {
>>> +        for (r = 0; r < cma->nranges; r++) {
>>> +            unsigned long start_pfn;
>>> +
>>>            cmr = &cma->ranges[r];
>>> +            start_pfn = r < allocrange ? early_pfn[r] : cmr->early_pfn;
>> 
>> Should this be r <= allocrange?

Yes. So I sent a v2 to fix it last Saturday.

https://lore.kernel.org/linux-mm/20260523060123.2207992-1-songmuchun@bytedance.com/

Thanks.

> 
> Yes, I think you are right. I missed that.
> 
> early_pfn[alloc_range] holds the last assignment, so we should start
> from the next one reading cmr->early_pfn.
> 
> 
> 
> --
> Oscar Salvador
> SUSE Labs