Hello! When PREEMPT_RT=y, spin locks are mapped to rt_mutex types, so using spinlock_check() + __raw_spin_lock_init() to initialize spin locks is incorrect, and would cause build errors. This v3 patch introduces __spin_lock_init() to initialize a spin lock with lockdep rquired information for PREEMPT_RT builds, and use it in the Rust helper. This patch was developed on top of linux-next/master. As a note, at the time of writing, RUST support for x86_64 depends on !(MITIGATION_RETHUNK && KASAN) || RUSTC_VERSION >= 108300. Miguel Ojeda pointed out that this can be avoided with Rust 1.83, to be released in 3 weeks (2024-11-28). In order to reproduce the problem rust must be available on the system. $ make LLVM=1 rustavailable With CONFIG_PREEMPT_RT=y, CONFIG_RUST=y, and CONFIG_DEBUG_SPINLOCK=y a x86_64 kernel can be built with $ make LLVM=1 -j$(nproc) bzImage The problem was reported at least in: https://lore.kernel.org/oe-kbuild-all/202409251238.vetlgXE9-lkp@xxxxxxxxx/ https://lore.kernel.org/all/20241107182411.57e2b418@xxxxxxxxxxxxxxxx/ Links to v1 and v2 where improvement suggestions were made: https://lore.kernel.org/all/20241014195253.1704625-1-ezulian@xxxxxxxxxx/ https://lore.kernel.org/all/20241106211215.2005909-1-ezulian@xxxxxxxxxx/ Version 2 changes: - Cleaned up style and incorporated feedback from reviewers Boqun Feng and Miguel Ojeda. Version 3 changes: - Addressed review comments from Boqun Feng. Improved commit title and description and used a proper 'Fixed:' tag. Thanks, Eder Zulian (1): rust: helpers: Avoid raw_spin_lock initialization for PREEMPT_RT include/linux/spinlock_rt.h | 15 +++++++-------- rust/helpers/spinlock.c | 8 ++++++-- 2 files changed, 13 insertions(+), 10 deletions(-) -- 2.47.0
