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From: Kees Cook <kees@kernel.org>
To: Petr Mladek <pmladek@suse.com>
Cc: Sergio Perez Gonzalez <sperezglz@gmail.com>,
	Vlastimil Babka <vbabka@suse.cz>,
	David Rientjes <rientjes@google.com>,
	Bagas Sanjaya <bagasdotme@gmail.com>,
	Jonathan Corbet <corbet@lwn.net>,
	Steven Rostedt <rostedt@goodmis.org>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	Sergey Senozhatsky <senozhatsky@chromium.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Christoph Lameter <cl@linux.com>,
	Pekka Enberg <penberg@kernel.org>,
	Joonsoo Kim <iamjoonsoo.kim@lge.com>,
	Roman Gushchin <roman.gushchin@linux.dev>,
	Harry Yoo <harry.yoo@oracle.com>,
	"Paul E. McKenney" <paulmck@kernel.org>,
	Randy Dunlap <rdunlap@infradead.org>,
	Tamir Duberstein <tamird@gmail.com>,
	Miguel Ojeda <ojeda@kernel.org>,
	Alice Ryhl <aliceryhl@google.com>,
	linux-doc@vger.kernel.org, linux-mm@kvack.org,
	Thomas Huth <thuth@redhat.com>,
	"Borislav Petkov (AMD)" <bp@alien8.de>,
	Ard Biesheuvel <ardb@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Andreas Hindborg <a.hindborg@kernel.org>,
	Stephen Boyd <swboyd@chromium.org>,
	linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
Subject: Re: [PATCH v2] slab: Decouple slab_debug and no_hash_pointers
Date: Thu, 5 Jun 2025 13:15:32 -0700	[thread overview]
Message-ID: <202506051314.D6EDFA91D@keescook> (raw)
In-Reply-To: <Z_-dPcdiGW0fo8Ji@pathway.suse.cz>

On Wed, Apr 16, 2025 at 02:06:21PM +0200, Petr Mladek wrote:
> On Tue 2025-04-15 10:02:33, Kees Cook wrote:
> > Some system owners use slab_debug=FPZ (or similar) as a hardening option,
> > but do not want to be forced into having kernel addresses exposed due
> > to the implicit "no_hash_pointers" boot param setting.[1]
> > 
> > Introduce the "hash_pointers" boot param, which defaults to "auto"
> > (the current behavior), but also includes "always" (forcing on hashing
> > even when "slab_debug=..." is defined), and "never". The existing
> > "no_hash_pointers" boot param becomes an alias for "hash_pointers=never".
> > 
> > This makes it possible to boot with "slab_debug=FPZ hash_pointers=always".
> > 
> > Link: https://github.com/KSPP/linux/issues/368 [1]
> > Fixes: 792702911f58 ("slub: force on no_hash_pointers when slub_debug is enabled")
> > Co-developed-by: Sergio Perez Gonzalez <sperezglz@gmail.com>
> > Signed-off-by: Sergio Perez Gonzalez <sperezglz@gmail.com>
> > Acked-by: Vlastimil Babka <vbabka@suse.cz>
> > Acked-by: David Rientjes <rientjes@google.com>
> > Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>
> > Signed-off-by: Kees Cook <kees@kernel.org>
> 
> Tested-by: Petr Mladek <pmladek@suse.com>
> Reviewed-by: Petr Mladek <pmladek@suse.com>
> 
> I am going to wait few more days for a potential feedback.
> I'll queue it for 6.16 unless anyone complains.

Hi,

Is this still planned for 6.16? I just noticed it wasn't in -next, and
we're almost to the end of the merge window...

-Kees

-- 
Kees Cook


  parent reply	other threads:[~2025-06-05 20:15 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-04-15 17:02 Kees Cook
2025-04-16 12:06 ` Petr Mladek
2025-04-16 17:52   ` Kees Cook
2025-06-05 20:15   ` Kees Cook [this message]
2025-06-09 14:39     ` Petr Mladek
2025-06-09 15:24       ` Kees Cook
2025-06-09 20:12         ` Andy Shevchenko
2025-06-10  8:35           ` Petr Mladek
2025-04-17 12:36 ` Rafael Aquini
2025-04-17 14:15 ` Harry Yoo
2025-04-18 20:13   ` Kees Cook
2025-04-21  9:43     ` Harry Yoo

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