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Howlett" , Madhavan Srinivasan , Mark Rutland , Michael Ellerman , Michal Hocko , Nicholas Piggin , Palmer Dabbelt , Paul Walmsley , "H. Peter Anvin" , Ritesh Harjani , Russell King , Shrikanth Hegde , Suren Baghdasaryan , Sven Schnelle , Thomas Gleixner , Vasily Gorbik , Vlastimil Babka , Will Deacon , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org Subject: Re: [PATCH] arch, mm: promote DEBUG_WX to CHECK_WX Message-ID: References: <20260925-direct-map-verify-wx-v1-1-7fd2f7d6d23b@kernel.org> <91d800d6-03f3-4068-8c12-618529a81528@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <91d800d6-03f3-4068-8c12-618529a81528@kernel.org> X-Stat-Signature: 4fz9ofypcat9j43omxgwema9s7grpz8w X-Rspam-User: X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 75B2D4000A X-HE-Tag: 1790414164-640928 X-HE-Meta: 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 IGQEw8z3 cUlFLSxBEHhQcf/tPFNXzwgnHjuudwh+CsZASjTOHzKHQqN2IDxm7BYT13KLComcuXSlNpB7yTcL3209X73WM42/Poz1QbUCF3Ul+8hhVWFXWqdYUqTTl7JQl3lPmjdzrd5B8IDOZRS8WZ196k4KiLy4LSYuILKySb317szr0ms+vJrWpv2XATR7L4I+6Q9J419V/S0N09NvoX3almYfwb2SSqy6NGrsSDjEeURULhgka2IWHLvhMg7IXcqAZ7la8VKvYMnTD+WrD326h9avLHq/oc0ksgD1vXTMw/Prq5tAZqpJKBzDRYgXJf1NXAbmhJcFMW88GhtxTzjScZrpQu4YqfiKZioWhbPo8uGowrP8ULBbHnErjQinmZUPVz7iwSpKqAV5cLF9vdkMZN1c4t8aK+5mpSXPIvFtrocl42Yb2PJE= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, Sep 25, 2026 at 01:01:51PM +0200, David Hildenbrand (Arm) wrote: > On 9/25/26 11:53, Mike Rapoport (Microsoft) wrote: > > Verification that the kernel does not have writable + executable > > mappings is about detecting security risks rather than a pure debug > > feature. > > > > Major distribution configurations enable it in their kernels as well as > > defconfigs of most architectures that have ARCH_HAS_DEBUG_WX. > > > > Rename relevant generic configuration options to use CHECK_WX and move > > their definitions from mm/Kconfig.debug to mm/Kconfig. > > > > For arm that does not widely enable it, only rename its variants of the > > config options. > > > > Enabling CHECK_WX adds a few kilobytes to the kernel binary and while > > the added size can be slightly reduced with churny updates of > > architecture implementations of ptdump, the core functionality takes > > most of the added size. It cannot be moved to .init.text because the > > verification has to happen after init sections are freed. > > > > With this, make generic CHECK_WX default to STRICT_KERNEL_RWX while > > still leaving users targeting small kernels the possibility to opt-out. > > > > Suggested-by: Dave Hansen > > Signed-off-by: Mike Rapoport (Microsoft) > > --- > > Makes sense to me > > Acked-by: David Hildenbrand (Arm) Similarly LGTM so: Acked-by: Lorenzo Stoakes (ARM) > > -- > Cheers, > > David -- Cheers, Lorenzo