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locking/ww_mutex: Add kselftests for ww_mutex ABBA deadlock detection

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Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maarten Lankhorst <dev@mblankhorst.nl>
Cc: Nicolai Hähnle <nhaehnle@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20161201114711.28697-6-chris@chris-wilson.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Chris Wilson 2016-12-01 11:47:08 +00:00 committed by Ingo Molnar
parent c22fb3807f
commit 70207686e4
1 changed files with 98 additions and 0 deletions
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98
kernel/locking/test-ww_mutex.c
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@ -153,6 +153,96 @@ out:
return ret;
}
struct test_abba {
struct work_struct work;
struct ww_mutex a_mutex;
struct ww_mutex b_mutex;
struct completion a_ready;
struct completion b_ready;
bool resolve;
int result;
};
static void test_abba_work(struct work_struct *work)
{
struct test_abba *abba = container_of(work, typeof(*abba), work);
struct ww_acquire_ctx ctx;
int err;
ww_acquire_init(&ctx, &ww_class);
ww_mutex_lock(&abba->b_mutex, &ctx);
complete(&abba->b_ready);
wait_for_completion(&abba->a_ready);
err = ww_mutex_lock(&abba->a_mutex, &ctx);
if (abba->resolve && err == -EDEADLK) {
ww_mutex_unlock(&abba->b_mutex);
ww_mutex_lock_slow(&abba->a_mutex, &ctx);
err = ww_mutex_lock(&abba->b_mutex, &ctx);
}
if (!err)
ww_mutex_unlock(&abba->a_mutex);
ww_mutex_unlock(&abba->b_mutex);
ww_acquire_fini(&ctx);
abba->result = err;
}
static int test_abba(bool resolve)
{
struct test_abba abba;
struct ww_acquire_ctx ctx;
int err, ret;
ww_mutex_init(&abba.a_mutex, &ww_class);
ww_mutex_init(&abba.b_mutex, &ww_class);
INIT_WORK_ONSTACK(&abba.work, test_abba_work);
init_completion(&abba.a_ready);
init_completion(&abba.b_ready);
abba.resolve = resolve;
schedule_work(&abba.work);
ww_acquire_init(&ctx, &ww_class);
ww_mutex_lock(&abba.a_mutex, &ctx);
complete(&abba.a_ready);
wait_for_completion(&abba.b_ready);
err = ww_mutex_lock(&abba.b_mutex, &ctx);
if (resolve && err == -EDEADLK) {
ww_mutex_unlock(&abba.a_mutex);
ww_mutex_lock_slow(&abba.b_mutex, &ctx);
err = ww_mutex_lock(&abba.a_mutex, &ctx);
}
if (!err)
ww_mutex_unlock(&abba.b_mutex);
ww_mutex_unlock(&abba.a_mutex);
ww_acquire_fini(&ctx);
flush_work(&abba.work);
destroy_work_on_stack(&abba.work);
ret = 0;
if (resolve) {
if (err || abba.result) {
pr_err("%s: failed to resolve ABBA deadlock, A err=%d, B err=%d\n",
__func__, err, abba.result);
ret = -EINVAL;
}
} else {
if (err != -EDEADLK && abba.result != -EDEADLK) {
pr_err("%s: missed ABBA deadlock, A err=%d, B err=%d\n",
__func__, err, abba.result);
ret = -EINVAL;
}
}
return ret;
}
static int __init test_ww_mutex_init(void)
{
int ret;
@ -165,6 +255,14 @@ static int __init test_ww_mutex_init(void)
if (ret)
return ret;
ret = test_abba(false);
if (ret)
return ret;
ret = test_abba(true);
if (ret)
return ret;
return 0;
}