kernel/linux.git/lib/locking-selftest.c, branch v7.2-rc1

lockdep/selftests: Restore sched_rt_mutex state on PREEMPT_RT

2026-06-03T09:38:47+00:00

The WW-mutex selftests deliberately exercise failing lock paths. On PREEMPT_RT, some of those paths enter the RT-mutex scheduler helpers. The change referenced by the Fixes tag made those helpers track RT-mutex scheduling state in current->sched_rt_mutex. The bit is normally cleared by the matching post-schedule helper, but some WW-mutex selftests disable the runtime debug_locks flag before that happens. With debug_locks cleared, lockdep_assert() does not evaluate the expression that clears the bit, leaving stale state for the next testcase. With CONFIG_PREEMPT_RT=y and CONFIG_DEBUG_LOCKING_API_SELFTESTS=y, that stale state produces warnings such as: WARNING: kernel/sched/core.c:7557 at rt_mutex_pre_schedule+0x26/0x2d RIP: 0010:rt_mutex_pre_schedule+0x26/0x2d Save and restore current->sched_rt_mutex around each testcase, matching the existing PREEMPT_RT cleanup for task-local migration and RCU state. Fixes: d14f9e930b90 ("locking/rtmutex: Use rt_mutex specific scheduler helpers") Assisted-by: Codex:gpt-5 Signed-off-by: Karl Mehltretter Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Sebastian Andrzej Siewior Link: https://patch.msgid.link/20260523185123.17482-3-kmehltretter@gmail.com

lockdep/selftests: Restore migrate_disable() state on PREEMPT_RT

2026-06-03T09:38:47+00:00

The lockdep selftests deliberately run unbalanced locking patterns. dotest() restores the task state they leave behind before running the next testcase. On PREEMPT_RT, spin_lock() uses migrate_disable() instead of disabling preemption. dotest() cleans up the resulting migration-disabled state, but that cleanup is still guarded by CONFIG_SMP. That used to match the scheduler data model, where migration_disabled was also CONFIG_SMP-only. The commit referenced below made SMP scheduler state unconditional, so CONFIG_SMP=n PREEMPT_RT kernels with CONFIG_DEBUG_LOCKING_API_SELFTESTS=y report success from the selftests and then trip over stale current->migration_disabled state: releasing a pinned lock bad: scheduling from the idle thread! Kernel panic - not syncing: Fatal exception Save and restore current->migration_disabled for every PREEMPT_RT build. Fixes: cac5cefbade9 ("sched/smp: Make SMP unconditional") Assisted-by: Codex:gpt-5 Signed-off-by: Karl Mehltretter Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Sebastian Andrzej Siewior Link: https://patch.msgid.link/20260523185123.17482-2-kmehltretter@gmail.com

treewide: Remove in_irq()

2025-10-24T19:39:27+00:00

This old alias for in_hardirq() has been marked as deprecated since 2020; remove the stragglers. Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Thomas Gleixner Link: https://patch.msgid.link/20251024180654.1691095-1-willy@infradead.org

locking/ww_mutex: Fix ww_mutex dummy lockdep map selftest warnings

2024-12-02T11:16:57+00:00

The below commit introduces a dummy lockdep map, but didn't get the initialization quite right (it should mimic the initialization of the real ww_mutex lockdep maps). It also introduced a separate locking api selftest failure. Fix these. Closes: https://lore.kernel.org/lkml/Zw19sMtnKdyOVQoh@boqun-archlinux/ Fixes: 823a566221a5 ("locking/ww_mutex: Adjust to lockdep nest_lock requirements") Reported-by: Boqun Feng Suggested-by: Boqun Feng Signed-off-by: Thomas Hellström Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20241127085430.3045-1-thomas.hellstrom@linux.intel.com

locking/lockdep: Add a test for lockdep_set_subclass()

2024-10-18T04:21:16+00:00

Add a test case to ensure that no new name string literal will be created in lockdep_set_subclass(), otherwise a warning will be triggered in look_up_lock_class(). Add this to catch the problem in the future. [boqun: Reword the title, replace #if with #ifdef and rename functions and variables] Signed-off-by: Ahmed Ehab Signed-off-by: Boqun Feng Link: https://lore.kernel.org/lkml/20240905011220.356973-1-bottaawesome633@gmail.com/

lockdep/selftests: Use SBRM APIs for wait context tests

2023-07-26T10:29:13+00:00

The "__cleanup__" attribute is already used for wait context tests, so using it for locking tests has already been proven working. Now since SBRM APIs are merged, let's use these APIs instead of a local guard framework. This also helps testing SBRM APIs. Note that originally the tests don't rely on the cleanup ordering of two variables in the same scope, but since now it's something we'd like to assume and rely on[1], drop the extra scope in inner_in_outer() function. Again this gives us another opportunity to test the compiler behavior. [1]: https://lore.kernel.org/lkml/CAHk-=whEsr6fuVSdsoNPokLR2fZiGuo_hCLyrS-LCw7hT_N7cQ@mail.gmail.com/ Signed-off-by: Boqun Feng Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20230715235257.110325-1-boqun.feng@gmail.com

lockdep/selftests: Adapt ww-tests for PREEMPT_RT

2021-12-04T09:56:24+00:00

The ww-mutex selftest operates directly on ww_mutex::base and assumes its type is struct mutex. This isn't true on PREEMPT_RT which turns the mutex into a rtmutex. Add a ww_mutex_base_ abstraction which maps to the relevant mutex_ or rt_mutex_ function. Change the CONFIG_DEBUG_MUTEXES ifdef to DEBUG_WW_MUTEXES. The latter is true for the MUTEX and RTMUTEX implementation of WW-MUTEX. The assignment is required in order to pass the tests. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20211129174654.668506-10-bigeasy@linutronix.de

lockdep/selftests: Skip the softirq related tests on PREEMPT_RT

2021-12-04T09:56:24+00:00

The softirq context on PREEMPT_RT is different compared to !PREEMPT_RT. As such lockdep_softirq_enter() is a nop and the all the "softirq safe" tests fail on PREEMPT_RT because there is no difference. Skip the softirq context tests on PREEMPT_RT. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20211129174654.668506-9-bigeasy@linutronix.de

lockdep/selftests: Unbalanced migrate_disable() & rcu_read_lock().

2021-12-04T09:56:24+00:00

The tests with unbalanced lock() + unlock() operation leave a modified preemption counter behind which is then reset to its original value after the test. The spin_lock() function on PREEMPT_RT does not include a preempt_disable() statement but migrate_disable() and read_rcu_lock(). As a consequence both counter never get back to their original value and the system explodes later after the selftest. In the double-unlock case on PREEMPT_RT, the migrate_disable() and RCU code will trigger a warning which should be avoided. These counter should not be decremented below their initial value. Save both counters and bring them back to their original value after the test. In the double-unlock case, increment both counter in advance to they become balanced after the double unlock. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20211129174654.668506-8-bigeasy@linutronix.de

lockdep/selftests: Avoid using local_lock_{acquire|release}().

2021-12-04T09:56:24+00:00

The local_lock related functions local_lock_acquire() local_lock_release() are part of the internal implementation and should be avoided. Define the lock as DEFINE_PER_CPU so the normal local_lock() function can be used. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20211129174654.668506-7-bigeasy@linutronix.de