linux-kernel - Re: [RFC PATCH] userfaultfd: support control over mm of remote PIDs

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Message-ID: <83827672-0996-4c25-9991-697ad443b6b3@redhat.com>
Date:   Mon, 27 Sep 2021 11:29:59 +0200
From:   David Hildenbrand <david@...hat.com>
To:     Nadav Amit <nadav.amit@...il.com>,
        Andrew Morton <akpm@...ux-foundation.org>
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        Nadav Amit <namit@...are.com>,
        Andrea Arcangeli <aarcange@...hat.com>,
        Mike Rapoport <rppt@...ux.vnet.ibm.com>,
        Peter Xu <peterx@...hat.com>
Subject: Re: [RFC PATCH] userfaultfd: support control over mm of remote PIDs

On 26.09.21 19:06, Nadav Amit wrote:
> From: Nadav Amit <namit@...are.com>
> 
> Non-cooperative mode is useful but only for forked processes.
> Userfaultfd can be useful to monitor, debug and manage memory of remote
> processes.
> 
> To support this mode, add a new flag, UFFD_REMOTE_PID, and an optional
> second argument to the userfaultfd syscall. When the flag is set, the
> second argument is assumed to be the PID of the process that is to be
> monitored. Otherwise the flag is ignored.
> 
> The syscall enforces that the caller has CAP_SYS_PTRACE to prevent
> misuse of this feature.

What supposed to happen if the target process intents to use uffd itself?

-- 
Thanks,

David / dhildenb