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authorSebastian Andrzej Siewior <bigeasy@linutronix.de>2020-12-15 20:43:13 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2020-12-15 22:46:16 -0800
commit45e3d5a2af1d53164cc5fbd22c5ceea0d163ad45 (patch)
treebfd7a5bf7e457fa0b9642571fe04dc34dc90c247
parent180644f80a0284bf5c9acdbd33760924fef14236 (diff)
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>
-rw-r--r--lib/test_lockup.c16
1 files changed, 16 insertions, 0 deletions
diff --git a/lib/test_lockup.c b/lib/test_lockup.c
index f1a020bcc763..864554e76973 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) ||
@@ -494,6 +509,7 @@ static int __init test_lockup_init(void)
SPINLOCK_MAGIC))
return -EINVAL;
#endif
+#endif
if ((wait_state != TASK_RUNNING ||
(call_cond_resched && !reacquire_locks) ||