Re: [PATCH] mm/madvise: elevate page refcount while isolating in process_madvise()

[Charan Teja Kalla]

On 12/15/2021 7:25 PM, Matthew Wilcox wrote:
> On Wed, Dec 15, 2021 at 05:53:39PM +0530, Charan Teja Reddy wrote:
>> The documentation of isolate_lru_page() says that, "it must be called
>> with an elevated refcount on the page", which is not followed while
>> isolating pages in process_madvise() system call with advise
>> MADV_PAGEOUT. Fix it.
> 
> We hold the mmap_lock over the call to this function, so the reference
> to the page from the page tables cannot go away.  There's no need to
> grab an extra reference here.

Thanks Matthew for clearing such fundamentals.

>