Re: [PATCH RFC 0/2] mm/page_alloc: free_pcppages_bulk safeguard

From: Mel Gorman
Date: Mon Aug 21 2023 - 06:32:41 EST


On Thu, Aug 17, 2023 at 11:05:22PM -0700, Chris Li wrote:
> In this patch series I want to safeguard
> the free_pcppage_bulk against change in the
> pcp->count outside of this function. e.g.
> by BPF program inject on the function tracepoint.
>
> I break up the patches into two seperate patches
> for the safeguard and clean up.
>
> Hopefully that is easier to review.
>
> Signed-off-by: Chris Li <chrisl@xxxxxxxxxx>

This sounds like a maintenance nightmare if internal state can be arbitrary
modified by a BPF program and still expected to work properly in all cases.
Every review would have to take into account "what if a BPF script modifies
state behind our back?"

--
Mel Gorman
SUSE Labs