On 2017-02-03 08:49:24 [-0800], Andy Ritger wrote:
> > So your problem is simply that your non-GPL module can't link anymore
> > with -RT. Would it help you if I simply replace the export for
> > mutex_destroy with EXPORT_SYMBOL and leave it the function as is?
>
> Yes, definitely.
So this is what I intend to add to the RT patch and I hope Ingo won't
object:
Alex Goins reported that mutex_destroy() on RT will force a GPL only symbol
which won't link and therefore fail on a non-GPL kernel module.
This does not happen on !RT and is a regression on RT which we would like to
avoid.
I try here the easy thing and to not use rt_mutex_destroy() if
CONFIG_DEBUG_MUTEXES is not enabled. This will still break for the DEBUG
configs so instead of adding a wrapper around rt_mutex_destroy() (which we have
for rt_mutex_lock() for instance) I am simply dropping the GPL part from the
export.
Reported-by: Alex Goins <agoins@xxxxxxxxxx>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
---
include/linux/mutex_rt.h | 5 +++++
kernel/locking/rtmutex.c | 3 +--
2 files changed, 6 insertions(+), 2 deletions(-)
--- a/include/linux/mutex_rt.h
+++ b/include/linux/mutex_rt.h
@@ -43,7 +43,12 @@ extern void __lockfunc _mutex_unlock(str
#define mutex_lock_killable(l) _mutex_lock_killable(l)
#define mutex_trylock(l) _mutex_trylock(l)
#define mutex_unlock(l) _mutex_unlock(l)
+
+#ifdef CONFIG_DEBUG_MUTEXES
#define mutex_destroy(l) rt_mutex_destroy(&(l)->lock)
+#else
+static inline void mutex_destroy(struct mutex *lock) {}
+#endif
#ifdef CONFIG_DEBUG_LOCK_ALLOC
# define mutex_lock_nested(l, s) _mutex_lock_nested(l, s)
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -2027,8 +2027,7 @@ void rt_mutex_destroy(struct rt_mutex *l
lock->magic = NULL;
#endif
}
-
-EXPORT_SYMBOL_GPL(rt_mutex_destroy);
+EXPORT_SYMBOL(rt_mutex_destroy);
/**
* __rt_mutex_init - initialize the rt lock
Sebastian
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