Module: xenomai-jki
Branch: for-upstream
Commit: 81025794136f0ec125e4204f00bea9a024a15abf
URL:
http://git.xenomai.org/?p=xenomai-jki.git;a=commit;h=81025794136f0ec125e4204f00bea9a024a15abf
Author: Jan Kiszka <jan.kis...@siemens.com>
Date: Sun Apr 25 16:16:32 2010 +0200
mutex-torture: Add test for disallowed lock stealing
This test case reflects an existing bug in the lock stealing
implementation: A lock is stolen from A and then released again. When A
wakes up, it acquires the lock via the in-kernel fastpath and holds it
while being busy. B preempts A and tries to acquire the lock as well. So
far it steals it due to the bug while it should simply boost A and wait
for the release.
Signed-off-by: Jan Kiszka <jan.kis...@siemens.com>
---
src/testsuite/unit/mutex-torture.c | 62 ++++++++++++++++++++++++++++++++++++
1 files changed, 62 insertions(+), 0 deletions(-)
diff --git a/src/testsuite/unit/mutex-torture.c
b/src/testsuite/unit/mutex-torture.c
index fdcada4..3512977 100644
--- a/src/testsuite/unit/mutex-torture.c
+++ b/src/testsuite/unit/mutex-torture.c
@@ -597,6 +597,67 @@ void lock_stealing(void)
"NOTE: lock_stealing mutex_trylock: not supported\n");
}
+void *victim(void *cookie)
+{
+ mutex_t *mutex = (mutex_t *) cookie;
+ unsigned long long start;
+
+ dispatch("victim pthread_detach", THREAD_DETACH, 1, 0);
+ dispatch("victim mutex_lock", MUTEX_LOCK, 1, 0, mutex);
+
+ start = rt_timer_tsc();
+ while (rt_timer_tsc2ns(rt_timer_tsc() - start) < 110000000);
+
+ dispatch("victim mutex_unlock", MUTEX_UNLOCK, 1, 0, mutex);
+
+ return cookie;
+}
+
+void deny_stealing(void)
+{
+ unsigned long long start, diff;
+ mutex_t mutex;
+ thread_t lowprio_tid;
+
+ fprintf(stderr, "deny_stealing\n");
+
+ dispatch("deny_stealing mutex_init", MUTEX_CREATE, 1, 0, &mutex, 1, 0);
+ dispatch("deny_stealing mutex_lock 1", MUTEX_LOCK, 1, 0, &mutex);
+
+ /* Main thread should have higher priority */
+ dispatch("deny_stealing thread_create", THREAD_CREATE, 1, 0,
+ &lowprio_tid, 1, victim, &mutex);
+
+ /* Give lowprio thread 1 more ms to block on the mutex */
+ ms_sleep(6);
+
+ dispatch("deny_stealing mutex_unlock 1", MUTEX_UNLOCK, 1, 0, &mutex);
+
+ /* Steal the lock for a short while */
+ dispatch("deny_stealing mutex_lock 2", MUTEX_LOCK, 1, 0, &mutex);
+ dispatch("deny_stealing mutex_unlock 2", MUTEX_UNLOCK, 1, 0, &mutex);
+
+ /* Give lowprio thread a chance to run */
+ ms_sleep(6);
+
+ /* Try to reacquire the lock, but the lowprio thread should hold it */
+ start = rt_timer_tsc();
+ dispatch("deny_stealing mutex_lock 3", MUTEX_LOCK, 1, 0, &mutex);
+ diff = rt_timer_tsc2ns(rt_timer_tsc() - start);
+ if (diff < 10000000) {
+ fprintf(stderr, "FAILURE: main, waited %Ld.%03u us\n",
+ diff / 1000, (unsigned) (diff % 1000));
+ exit(EXIT_FAILURE);
+ }
+
+ dispatch("deny_stealing mutex_unlock 3", MUTEX_UNLOCK, 1, 0, &mutex);
+
+ /* Let waiter_lowprio a chance to run */
+ ms_sleep(20);
+
+ dispatch("deny_stealing mutex_destroy", MUTEX_DESTROY, 1, 0, &mutex);
+}
+
struct cond_mutex {
mutex_t *mutex;
cond_t *cond;
@@ -739,6 +800,7 @@ int main(void)
mode_switch();
pi_wait();
lock_stealing();
+ deny_stealing();
simple_condwait();
recursive_condwait();
fprintf(stderr, "Test OK\n");
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