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author | David Edmondson <david.edmondson@oracle.com> | 2021-03-25 12:29:41 +0100 |
---|---|---|
committer | Stefan Hajnoczi <stefanha@redhat.com> | 2021-03-31 10:44:21 +0100 |
commit | b6489ac06695e257ea0a9841364577e247fdee30 (patch) | |
tree | 99a6e235d356604850385ff49cce3b68e5b90c01 /tests | |
parent | 25bc2daed0482732a2dd258dde4386f505582fa9 (diff) |
test-coroutine: Add rwlock downgrade test
Test that downgrading an rwlock does not result in a failure to
schedule coroutines queued on the rwlock.
The diagram associated with test_co_rwlock_downgrade() describes the
intended behaviour, but what was observed previously corresponds to:
| c1 | c2 | c3 | c4 |
|--------+------------+------------+----------|
| rdlock | | | |
| yield | | | |
| | wrlock | | |
| | <queued> | | |
| | | rdlock | |
| | | <queued> | |
| | | | wrlock |
| | | | <queued> |
| unlock | | | |
| yield | | | |
| | <dequeued> | | |
| | downgrade | | |
| | ... | | |
| | unlock | | |
| | | <dequeued> | |
| | | <queued> | |
This results in a failure...
ERROR:../tests/test-coroutine.c:369:test_co_rwlock_downgrade: assertion failed: (c3_done)
Bail out! ERROR:../tests/test-coroutine.c:369:test_co_rwlock_downgrade: assertion failed: (c3_done)
...as a result of the c3 coroutine failing to run to completion.
Signed-off-by: David Edmondson <david.edmondson@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 20210325112941.365238-7-pbonzini@redhat.com
Message-Id: <20210309144015.557477-5-david.edmondson@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'tests')
-rw-r--r-- | tests/unit/test-coroutine.c | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/tests/unit/test-coroutine.c b/tests/unit/test-coroutine.c index 6e6f51d480..aa77a3bcb3 100644 --- a/tests/unit/test-coroutine.c +++ b/tests/unit/test-coroutine.c @@ -325,6 +325,104 @@ static void test_co_rwlock_upgrade(void) g_assert(c2_done); } +static void coroutine_fn rwlock_rdlock_yield(void *opaque) +{ + qemu_co_rwlock_rdlock(&rwlock); + qemu_coroutine_yield(); + + qemu_co_rwlock_unlock(&rwlock); + qemu_coroutine_yield(); + + *(bool *)opaque = true; +} + +static void coroutine_fn rwlock_wrlock_downgrade(void *opaque) +{ + qemu_co_rwlock_wrlock(&rwlock); + + qemu_co_rwlock_downgrade(&rwlock); + qemu_co_rwlock_unlock(&rwlock); + *(bool *)opaque = true; +} + +static void coroutine_fn rwlock_rdlock(void *opaque) +{ + qemu_co_rwlock_rdlock(&rwlock); + + qemu_co_rwlock_unlock(&rwlock); + *(bool *)opaque = true; +} + +static void coroutine_fn rwlock_wrlock(void *opaque) +{ + qemu_co_rwlock_wrlock(&rwlock); + + qemu_co_rwlock_unlock(&rwlock); + *(bool *)opaque = true; +} + +/* + * Check that downgrading a reader-writer lock does not cause a hang. + * + * Four coroutines are used to produce a situation where there are + * both reader and writer hopefuls waiting to acquire an rwlock that + * is held by a reader. + * + * The correct sequence of operations we aim to provoke can be + * represented as: + * + * | c1 | c2 | c3 | c4 | + * |--------+------------+------------+------------| + * | rdlock | | | | + * | yield | | | | + * | | wrlock | | | + * | | <queued> | | | + * | | | rdlock | | + * | | | <queued> | | + * | | | | wrlock | + * | | | | <queued> | + * | unlock | | | | + * | yield | | | | + * | | <dequeued> | | | + * | | downgrade | | | + * | | | <dequeued> | | + * | | | unlock | | + * | | ... | | | + * | | unlock | | | + * | | | | <dequeued> | + * | | | | unlock | + */ +static void test_co_rwlock_downgrade(void) +{ + bool c1_done = false; + bool c2_done = false; + bool c3_done = false; + bool c4_done = false; + Coroutine *c1, *c2, *c3, *c4; + + qemu_co_rwlock_init(&rwlock); + + c1 = qemu_coroutine_create(rwlock_rdlock_yield, &c1_done); + c2 = qemu_coroutine_create(rwlock_wrlock_downgrade, &c2_done); + c3 = qemu_coroutine_create(rwlock_rdlock, &c3_done); + c4 = qemu_coroutine_create(rwlock_wrlock, &c4_done); + + qemu_coroutine_enter(c1); + qemu_coroutine_enter(c2); + qemu_coroutine_enter(c3); + qemu_coroutine_enter(c4); + + qemu_coroutine_enter(c1); + + g_assert(c2_done); + g_assert(c3_done); + g_assert(c4_done); + + qemu_coroutine_enter(c1); + + g_assert(c1_done); +} + /* * Check that creation, enter, and return work */ @@ -563,6 +661,7 @@ int main(int argc, char **argv) g_test_add_func("/locking/co-mutex", test_co_mutex); g_test_add_func("/locking/co-mutex/lockable", test_co_mutex_lockable); g_test_add_func("/locking/co-rwlock/upgrade", test_co_rwlock_upgrade); + g_test_add_func("/locking/co-rwlock/downgrade", test_co_rwlock_downgrade); if (g_test_perf()) { g_test_add_func("/perf/lifecycle", perf_lifecycle); g_test_add_func("/perf/nesting", perf_nesting); |