selftests/liveupdate: add userspace API selftests

2025-11-27T22:24:41+00:00

Introduce a selftest suite for LUO. These tests validate the core userspace-facing API provided by the /dev/liveupdate device and its associated ioctls. The suite covers fundamental device behavior, session management, and the file preservation mechanism using memfd as a test case. This provides regression testing for the LUO uAPI. The following functionality is verified: Device Access: Basic open and close operations on /dev/liveupdate. Enforcement of exclusive device access (verifying EBUSY on a second open). Session Management: Successful creation of sessions with unique names. Failure to create sessions with duplicate names. File Preservation: Preserving a single memfd and verifying its content remains intact post-preservation. Preserving multiple memfds within a single session, each with unique data. A complex scenario involving multiple sessions, each containing a mix of empty and data-filled memfds. Note: This test suite is limited to verifying the pre-kexec functionality of LUO (e.g., session creation, file preservation). The post-kexec restoration of resources is not covered, as the kselftest framework does not currently support orchestrating a reboot and continuing execution in the new kernel. Link: https://lkml.kernel.org/r/20251125165850.3389713-17-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin Reviewed-by: Pratyush Yadav Reviewed-by: Mike Rapoport (Microsoft) Tested-by: David Matlack Cc: Aleksander Lobakin Cc: Alexander Graf Cc: Alice Ryhl Cc: Andriy Shevchenko Cc: anish kumar Cc: Anna Schumaker Cc: Bartosz Golaszewski Cc: Bjorn Helgaas Cc: Borislav Betkov Cc: Chanwoo Choi Cc: Chen Ridong Cc: Chris Li Cc: Christian Brauner Cc: Daniel Wagner Cc: Danilo Krummrich Cc: Dan Williams Cc: David Hildenbrand Cc: David Jeffery Cc: David Rientjes Cc: Greg Kroah-Hartman Cc: Guixin Liu Cc: "H. Peter Anvin" Cc: Hugh Dickins Cc: Ilpo Järvinen Cc: Ingo Molnar Cc: Ira Weiny Cc: Jann Horn Cc: Jason Gunthorpe Cc: Jens Axboe Cc: Joanthan Cameron Cc: Joel Granados Cc: Johannes Weiner Cc: Jonathan Corbet Cc: Lennart Poettering Cc: Leon Romanovsky Cc: Leon Romanovsky Cc: Lukas Wunner Cc: Marc Rutland Cc: Masahiro Yamada Cc: Matthew Maurer Cc: Miguel Ojeda Cc: Myugnjoo Ham Cc: Parav Pandit Cc: Pratyush Yadav Cc: Randy Dunlap Cc: Roman Gushchin Cc: Saeed Mahameed Cc: Samiullah Khawaja Cc: Song Liu Cc: Steven Rostedt Cc: Stuart Hayes Cc: Tejun Heo Cc: Thomas Gleinxer Cc: Thomas Weißschuh Cc: Vincent Guittot Cc: William Tu Cc: Yoann Congal Cc: Zhu Yanjun Cc: Zijun Hu Signed-off-by: Andrew Morton

kernel/linux.git/tools/testing/selftests/liveupdate/config, branch v6.19.12

selftests/liveupdate: add userspace API selftests