From: Kees Cook <keescook@chromium.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Christoph Hellwig <hch@lst.de>, Will Deacon <will@kernel.org>,
andreyknvl@gmail.com, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, Mel Gorman <mgorman@suse.de>
Subject: Re: [PATCH] mm/vmalloc: Don't allow VM_NO_GUARD on vmap()
Date: Thu, 16 Sep 2021 08:57:36 -0700 [thread overview]
Message-ID: <202109160857.8F4AAE1A19@keescook> (raw)
In-Reply-To: <YUMfdA36fuyZ+/xt@hirez.programming.kicks-ass.net>
On Thu, Sep 16, 2021 at 12:41:56PM +0200, Peter Zijlstra wrote:
>
> The vmalloc guard pages are added on top of each allocation, thereby
> isolating any two allocations from one another. The top guard of the
> lower allocation is the bottom guard guard of the higher allocation
> etc.
>
> Therefore VM_NO_GUARD is dangerous; it breaks the basic premise of
> isolating separate allocations.
>
> There are only two in-tree users of this flag, neither of which use it
> through the exported interface. Ensure it stays this way.
>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Yes, please. :)
Acked-by: Kees Cook <keescook@chromium.org>
--
Kees Cook
prev parent reply other threads:[~2021-09-16 15:57 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-16 10:41 Peter Zijlstra
2021-09-16 11:23 ` Christoph Hellwig
2021-09-16 12:34 ` David Hildenbrand
2021-09-16 13:30 ` Will Deacon
2021-09-16 15:57 ` Kees Cook [this message]
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