Re: [PATCH] mm/mincore: allow for making sys_mincore() privileged

From: Bernd Petrovitsch
Date: Tue Jan 08 2019 - 04:15:17 EST


On 05/01/2019 20:38, Vlastimil Babka wrote:
[...]
> I was thinking about "return true" here, assuming that userspace generally wants
> to ensure itself there won't be page faults when it starts doing something
> critical, and if it sees a "false" it will try to do some kind of prefaulting,
> possibly in a loop. There might be somebody trying to make sure something is out

Isn't that racy by design as the pages may get flushed out after the check?
Shouldn't the application use e.g. mlock()/.... to guarantee no page
faults in the first place?

MfG,
Bernd
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