From: Dave Hansen <dave.hansen@intel.com>
To: Matteo Rizzo <matteorizzo@google.com>, Ingo Molnar <mingo@kernel.org>
Cc: "Lameter, Christopher" <cl@os.amperecomputing.com>,
penberg@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com,
akpm@linux-foundation.org, vbabka@suse.cz,
roman.gushchin@linux.dev, 42.hyeyoo@gmail.com,
keescook@chromium.org, linux-kernel@vger.kernel.org,
linux-doc@vger.kernel.org, linux-mm@kvack.org,
linux-hardening@vger.kernel.org, tglx@linutronix.de,
mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com,
x86@kernel.org, hpa@zytor.com, corbet@lwn.net, luto@kernel.org,
peterz@infradead.org, jannh@google.com, evn@google.com,
poprdi@google.com, jordyzomer@google.com,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [RFC PATCH 00/14] Prevent cross-cache attacks in the SLUB allocator
Date: Tue, 19 Sep 2023 08:56:30 -0700 [thread overview]
Message-ID: <d04f77ff-e95b-6012-9be6-daf20ba9e272@intel.com> (raw)
In-Reply-To: <CAHKB1wKneke-dyvMY0JtW-xwW8m=GaUdafoAqdCE0B9csY7_bw@mail.gmail.com>
On 9/19/23 06:42, Matteo Rizzo wrote:
> On Mon, 18 Sept 2023 at 19:39, Ingo Molnar <mingo@kernel.org> wrote:
>> What's the split of the increase in overhead due to SLAB_VIRTUAL=y, between
>> user-space execution and kernel-space execution?
>>
> Same benchmark as before (compiling a kernel on a system running the patched
> kernel):
Thanks for running those. One more situation that comes to mind is how
this will act under memory pressure. Will some memory pressure make
contention on 'slub_kworker_lock' visible or make the global TLB flushes
less bearable?
In any case, none of this looks _catastrophic_. It's surely a cost that
some folks will pay.
But I really do think it needs to be more dynamic. There are a _couple_
of reasons for this. If it's only a compile-time option, it's never
going to get turned on except for maybe ChromeOS and the datacenter
folks that are paranoid. I suspect the distros will never turn it on.
A lot of questions get easier if you can disable/enable it at runtime.
For instance, what do you do if the virtual area fills up? You _could_
just go back to handing out direct map addresses. Less secure? Yep.
But better than crashing (for some folks).
It also opens up the door to do this per-slab. That alone would be a
handy debugging option.
next prev parent reply other threads:[~2023-09-19 15:56 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-15 10:59 [RFC PATCH 00/14] Prevent cross-cache attacks in the SLUB allocator Matteo Rizzo
2023-09-15 10:59 ` [RFC PATCH 01/14] mm/slub: don't try to dereference invalid freepointers Matteo Rizzo
2023-09-15 20:50 ` Kees Cook
2023-09-30 11:04 ` Hyeonggon Yoo
2023-09-15 10:59 ` [RFC PATCH 02/14] mm/slub: add is_slab_addr/is_slab_page helpers Matteo Rizzo
2023-09-15 20:55 ` Kees Cook
2023-09-15 10:59 ` [RFC PATCH 03/14] mm/slub: move kmem_cache_order_objects to slab.h Matteo Rizzo
2023-09-15 20:56 ` Kees Cook
2023-09-15 10:59 ` [RFC PATCH 04/14] mm: use virt_to_slab instead of folio_slab Matteo Rizzo
2023-09-15 20:59 ` Kees Cook
2023-09-15 10:59 ` [RFC PATCH 05/14] mm/slub: create folio_set/clear_slab helpers Matteo Rizzo
2023-09-15 21:02 ` Kees Cook
2023-09-15 10:59 ` [RFC PATCH 06/14] mm/slub: pass additional args to alloc_slab_page Matteo Rizzo
2023-09-15 21:03 ` Kees Cook
2023-09-15 10:59 ` [RFC PATCH 07/14] mm/slub: pass slab pointer to the freeptr decode helper Matteo Rizzo
2023-09-15 21:06 ` Kees Cook
2023-09-15 10:59 ` [RFC PATCH 08/14] security: introduce CONFIG_SLAB_VIRTUAL Matteo Rizzo
2023-09-15 21:07 ` Kees Cook
2023-09-15 10:59 ` [RFC PATCH 09/14] mm/slub: add the slab freelists to kmem_cache Matteo Rizzo
2023-09-15 21:08 ` Kees Cook
2023-09-15 10:59 ` [RFC PATCH 10/14] x86: Create virtual memory region for SLUB Matteo Rizzo
2023-09-15 21:13 ` Kees Cook
2023-09-15 21:49 ` Dave Hansen
2023-09-18 8:54 ` Matteo Rizzo
2023-09-15 10:59 ` [RFC PATCH 11/14] mm/slub: allocate slabs from virtual memory Matteo Rizzo
2023-09-15 21:22 ` Kees Cook
2023-09-15 21:57 ` Dave Hansen
2023-10-11 9:17 ` Matteo Rizzo
2023-09-15 10:59 ` [RFC PATCH 12/14] mm/slub: introduce the deallocated_pages sysfs attribute Matteo Rizzo
2023-09-15 21:23 ` Kees Cook
2023-09-15 10:59 ` [RFC PATCH 13/14] mm/slub: sanity-check freepointers Matteo Rizzo
2023-09-15 21:26 ` Kees Cook
2023-09-15 10:59 ` [RFC PATCH 14/14] security: add documentation for SLAB_VIRTUAL Matteo Rizzo
2023-09-15 21:34 ` Kees Cook
2023-09-20 9:04 ` Vlastimil Babka
2023-09-15 15:19 ` [RFC PATCH 00/14] Prevent cross-cache attacks in the SLUB allocator Dave Hansen
2023-09-15 16:30 ` Lameter, Christopher
2023-09-18 12:08 ` Matteo Rizzo
2023-09-18 17:39 ` Ingo Molnar
2023-09-18 18:05 ` Linus Torvalds
2023-09-19 15:48 ` Matteo Rizzo
2023-09-19 16:02 ` Dave Hansen
2023-09-19 17:56 ` Kees Cook
2023-09-19 18:49 ` Linus Torvalds
2023-09-19 13:42 ` Matteo Rizzo
2023-09-19 15:56 ` Dave Hansen [this message]
2023-09-20 7:44 ` Ingo Molnar
2023-09-20 8:49 ` Vlastimil Babka
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