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envelope-from=jgg@nvidia.com; helo=PH8PR06CU001.outbound.protection.outlook.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.069, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_NONE=0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-arm@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-arm-bounces+qemu-arm=archiver.kernel.org@nongnu.org Sender: qemu-arm-bounces+qemu-arm=archiver.kernel.org@nongnu.org On Wed, Jan 21, 2026 at 02:21:17PM +0000, Peter Maydell wrote: > But it looks to me like this is a bug in the Linux headers: > they seem to have changed in a non-backwards compatible way, > and possibly even in a way that makes it not possible for > userspace code to use ifdefs to handle "maybe the header > is the old version or the new version". Technically Linux doesn't provide an API guarentee, just an ABI guarentee. Ie we don't guarentee all old userspace compiles with the new headers, we just guarentee that once compiled it keeps working.. You need to use something like configure and compile trial tests to figure things out. IMHO this happens rarely enough that what is proposed here as a single patch is the best option. Jason