Re: [PATCH] prctl: Don't compile some of prctl functions when CRUI

From: Cyrill Gorcunov
Date: Wed Apr 17 2019 - 08:38:47 EST

On Wed, Apr 17, 2019 at 02:23:50PM +0200, Michal Koutný wrote:
> Hi.
> I see this discussion somewhat faded away since the previous year.
> There was rework [1] that reduced (ab)use of mmap_sem in prctl
> functions.
> Actually, there still remains the down_write() in prctl_set_mm.
> I considered at least replacing it with the mm_struct.arg_lock +
> down_read() but then I learnt about this thread intending to remove that
> part completely. I wouldn't oppose if CRIU is the sole (aware) user.
> Ad the bot build issue, I could build the kernel both with
> fine after applying the two proposed patches.
> What is the current state? Perhaps, this change should be CCed to
> linux-api@xxxxxxxxxxxxxxx(?).
> [1]

Hi! I've a bit vague memory what we've ended up with, but iirc there was
a problem with brk() syscall or similar. Then I think we left everything
as is. I think there is no much activity in this prctl area now as far
as i know (replying to what is current state).