From 45e3d5a2af1d53164cc5fbd22c5ceea0d163ad45 Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Date: Tue, 15 Dec 2020 20:43:13 -0800 Subject: [PATCH] lib/test_lockup.c: minimum fix to get it compiled on PREEMPT_RT On PREEMPT_RT the locks are quite different so they can't be tested as it is done below. The alternative is to test for the waitlock within rtmutex. This is the bare minimun to get it compiled. Problems which exist on PREEMP_RT: - none of the locks (spinlock_t, rwlock_t, mutex_t, rw_semaphore) may be acquired with disabled preemption or interrupts. If I read the code correct the it is possible to acquire a mutex_t with disabled interrupts. I don't know how to obtain a lock pointer. Technically they are not exported to userland. - memory can not be allocated with disabled preemption or interrupts even with GFP_ATOMIC. Link: https://lkml.kernel.org/r/20201028181041.xyeothhkouc3p4md@linutronix.de Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> --- lib/test_lockup.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/lib/test_lockup.c b/lib/test_lockup.c index f1a020bcc763e..864554e769738 100644 --- a/lib/test_lockup.c +++ b/lib/test_lockup.c @@ -480,6 +480,21 @@ static int __init test_lockup_init(void) return -EINVAL; #ifdef CONFIG_DEBUG_SPINLOCK +#ifdef CONFIG_PREEMPT_RT + if (test_magic(lock_spinlock_ptr, + offsetof(spinlock_t, lock.wait_lock.magic), + SPINLOCK_MAGIC) || + test_magic(lock_rwlock_ptr, + offsetof(rwlock_t, rtmutex.wait_lock.magic), + SPINLOCK_MAGIC) || + test_magic(lock_mutex_ptr, + offsetof(struct mutex, lock.wait_lock.magic), + SPINLOCK_MAGIC) || + test_magic(lock_rwsem_ptr, + offsetof(struct rw_semaphore, rtmutex.wait_lock.magic), + SPINLOCK_MAGIC)) + return -EINVAL; +#else if (test_magic(lock_spinlock_ptr, offsetof(spinlock_t, rlock.magic), SPINLOCK_MAGIC) || @@ -493,6 +508,7 @@ static int __init test_lockup_init(void) offsetof(struct rw_semaphore, wait_lock.magic), SPINLOCK_MAGIC)) return -EINVAL; +#endif #endif if ((wait_state != TASK_RUNNING || -- GitLab