None of the ww_mutex codepaths should be taken in the 'normal' mutex calls. The easiest way to verify this is by using the normal mutex calls, and making sure o.ctx is unmodified.
Signed-off-by: Maarten Lankhorst maarten.lankhorst@canonical.com --- lib/locking-selftest.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 62 insertions(+)
diff --git a/lib/locking-selftest.c b/lib/locking-selftest.c index 9962262..37faefd 100644 --- a/lib/locking-selftest.c +++ b/lib/locking-selftest.c @@ -1162,6 +1162,67 @@ static void ww_test_fail_acquire(void) #endif }
+static void ww_test_normal(void) +{ + int ret; + + WWAI(&t); + + /* + * None of the ww_mutex codepaths should be taken in the 'normal' + * mutex calls. The easiest way to verify this is by using the + * normal mutex calls, and making sure o.ctx is unmodified. + */ + + /* mutex_lock (and indirectly, mutex_lock_nested) */ + o.ctx = (void *)~0UL; + mutex_lock(&o.base); + mutex_unlock(&o.base); + WARN_ON(o.ctx != (void *)~0UL); + + /* mutex_lock_interruptible (and *_nested) */ + o.ctx = (void *)~0UL; + ret = mutex_lock_interruptible(&o.base); + if (!ret) + mutex_unlock(&o.base); + else + WARN_ON(1); + WARN_ON(o.ctx != (void *)~0UL); + + /* mutex_lock_killable (and *_nested) */ + o.ctx = (void *)~0UL; + ret = mutex_lock_killable(&o.base); + if (!ret) + mutex_unlock(&o.base); + else + WARN_ON(1); + WARN_ON(o.ctx != (void *)~0UL); + + /* trylock, succeeding */ + o.ctx = (void *)~0UL; + ret = mutex_trylock(&o.base); + WARN_ON(!ret); + if (ret) + mutex_unlock(&o.base); + else + WARN_ON(1); + WARN_ON(o.ctx != (void *)~0UL); + + /* trylock, failing */ + o.ctx = (void *)~0UL; + mutex_lock(&o.base); + ret = mutex_trylock(&o.base); + WARN_ON(ret); + mutex_unlock(&o.base); + WARN_ON(o.ctx != (void *)~0UL); + + /* nest_lock */ + o.ctx = (void *)~0UL; + mutex_lock_nest_lock(&o.base, &t); + mutex_unlock(&o.base); + WARN_ON(o.ctx != (void *)~0UL); +} + static void ww_test_two_contexts(void) { WWAI(&t); @@ -1415,6 +1476,7 @@ static void ww_tests(void)
print_testname("ww api failures"); dotest(ww_test_fail_acquire, SUCCESS, LOCKTYPE_WW); + dotest(ww_test_normal, SUCCESS, LOCKTYPE_WW); dotest(ww_test_unneeded_slow, FAILURE, LOCKTYPE_WW); printk("\n");