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Wysocki" , Danilo Krummrich , Daniel Scally , Heikki Krogerus , Sakari Ailus , linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, driver-core@lists.linux.dev Subject: Re: [PATCH v2 3/4] software node: verify that property data is not on stack Message-ID: References: <20260329-property-gpio-fix-v2-0-3cca5ba136d8@gmail.com> <20260329-property-gpio-fix-v2-3-3cca5ba136d8@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@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: On Mon, Mar 30, 2026 at 01:33:47PM +0300, Andy Shevchenko wrote: > On Sun, Mar 29, 2026 at 07:27:50PM -0700, Dmitry Torokhov wrote: > > When registering a software node, ensure that the property data is not > > located on the stack, as it is expected to persist for the lifetime of > > the node. > > ... > > > + for (prop = node->properties; prop && prop->name; prop++) { > > + if (!prop->is_inline && object_is_on_stack(prop->pointer)) { > > I read more about this... Any code that uses vmalloc() (or potentially may > switch to it from regular allocator with help of kvalloc() and similar) will > fail now. While it might be no issue right now, this may become a such. So > with this check in place you put a requirement that properties can only be > allocated from a kernel low memory heap and not vm. Can you tell me more about this? As far as I can see it will actually have false negatives with CONFIG_VMAP_STACK, but should be OK not trigger with vmalloced memory... But I am genuinely interested to know more. Thanks. -- Dmitry