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lib/test_lockup.c: minimum fix to get it compiled on PREEMPT_RT

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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>
This commit is contained in:
Sebastian Andrzej Siewior 2020-12-15 20:43:13 -08:00 committed by Linus Torvalds
parent 180644f80a
commit 45e3d5a2af
1 changed files with 16 additions and 0 deletions
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16
lib/test_lockup.c
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@ -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 ||