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McKenney" , Randy Dunlap , Tamir Duberstein , Miguel Ojeda , Alice Ryhl , linux-doc@vger.kernel.org, linux-mm@kvack.org, Thomas Huth , "Borislav Petkov (AMD)" , Ard Biesheuvel , Greg Kroah-Hartman , Andreas Hindborg , Stephen Boyd , linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: Re: [PATCH v2] slab: Decouple slab_debug and no_hash_pointers Message-ID: References: <20250415170232.it.467-kees@kernel.org> <202506051314.D6EDFA91D@keescook> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <202506051314.D6EDFA91D@keescook> On Thu 2025-06-05 13:15:32, Kees Cook wrote: > 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 > > > Signed-off-by: Sergio Perez Gonzalez > > > Acked-by: Vlastimil Babka > > > Acked-by: David Rientjes > > > Reviewed-by: Bagas Sanjaya > > > Signed-off-by: Kees Cook > > > > Tested-by: Petr Mladek > > Reviewed-by: Petr Mladek > > > > 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... I am terribly sorry. I have forgot this patch... I have just pushed it into printk/linux.git, branch for-6.17-hash_pointers. Also I updated the documentation, aka applied the diff from https://lore.kernel.org/r/202504181307.254F81843@keescook See https://web.git.kernel.org/pub/scm/linux/kernel/git/printk/linux.git/commit/?h=for-6.17-hash_pointers&id=de1c831a7898f164c1c2703c6b2b9e4fb4bebefc As the branch name suggests, I am going to push it for 6.17. If it is too late for you then please let me know. Best Regards, Petr