coroutine: Assert that no locks are held on termination
A coroutine that takes a lock must also release it again. If the
coroutine terminates without having released all its locks, it's buggy
and we'll probably run into a deadlock sooner or later. Make sure that
we don't get such cases.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
diff --git a/util/qemu-coroutine-lock.c b/util/qemu-coroutine-lock.c
index f30ee81..14cf9ce 100644
--- a/util/qemu-coroutine-lock.c
+++ b/util/qemu-coroutine-lock.c
@@ -130,6 +130,7 @@
mutex->locked = true;
mutex->holder = self;
+ self->locks_held++;
trace_qemu_co_mutex_lock_return(mutex, self);
}
@@ -146,6 +147,7 @@
mutex->locked = false;
mutex->holder = NULL;
+ self->locks_held--;
qemu_co_queue_next(&mutex->queue);
trace_qemu_co_mutex_unlock_return(mutex, self);
@@ -159,14 +161,19 @@
void qemu_co_rwlock_rdlock(CoRwlock *lock)
{
+ Coroutine *self = qemu_coroutine_self();
+
while (lock->writer) {
qemu_co_queue_wait(&lock->queue);
}
lock->reader++;
+ self->locks_held++;
}
void qemu_co_rwlock_unlock(CoRwlock *lock)
{
+ Coroutine *self = qemu_coroutine_self();
+
assert(qemu_in_coroutine());
if (lock->writer) {
lock->writer = false;
@@ -179,12 +186,16 @@
qemu_co_queue_next(&lock->queue);
}
}
+ self->locks_held--;
}
void qemu_co_rwlock_wrlock(CoRwlock *lock)
{
+ Coroutine *self = qemu_coroutine_self();
+
while (lock->writer || lock->reader) {
qemu_co_queue_wait(&lock->queue);
}
lock->writer = true;
+ self->locks_held++;
}
