diff --git a/CHANGELOG.md b/CHANGELOG.md
index e845c81..b377a33 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+
+- Calling `ovni_thread_isready()` after `ovni_thread_free()` now returns 0.
+
 ## [1.5.0] - 2023-12-15
 
 ### Added
diff --git a/src/rt/ovni.c b/src/rt/ovni.c
index 1691bcf..3c7bcdf 100644
--- a/src/rt/ovni.c
+++ b/src/rt/ovni.c
@@ -26,6 +26,7 @@ struct ovni_rthread {
 	int streamfd;
 
 	int ready;
+	int finished;
 
 	/* The number of bytes filled with events */
 	size_t evlen;
@@ -552,6 +553,9 @@ ovni_thread_init(pid_t tid)
 		return;
 	}
 
+	if (rthread.finished)
+		die("thread %d has finished, cannot init again", tid);
+
 	if (tid == 0)
 		die("cannot use tid=%d", tid);
 
@@ -578,6 +582,9 @@ ovni_thread_init(pid_t tid)
 void
 ovni_thread_free(void)
 {
+	if (rthread.finished)
+		die("thread already finished");
+
 	if (!rthread.ready)
 		die("thread not initialized");
 
@@ -597,6 +604,9 @@ ovni_thread_free(void)
 
 	close(rthread.streamfd);
 	rthread.streamfd = -1;
+
+	rthread.ready = 0;
+	rthread.finished = 1;
 }
 
 int
diff --git a/test/emu/ovni/CMakeLists.txt b/test/emu/ovni/CMakeLists.txt
index 7f28418..a77ad4e 100644
--- a/test/emu/ovni/CMakeLists.txt
+++ b/test/emu/ovni/CMakeLists.txt
@@ -22,6 +22,7 @@ test_emu(require-bad-version.c SHOULD_FAIL REGEX "unsupported ovni model version
 test_emu(require-compat.c REGEX "loading trace in compatibility mode")
 test_emu(require-repeated.c)
 test_emu(thread-crash.c SHOULD_FAIL REGEX "incomplete stream")
+test_emu(thread-free-isready.c)
 test_emu(flush-tmpdir.c MP DRIVER "flush-tmpdir.driver.sh")
 test_emu(tmpdir-metadata.c MP DRIVER "tmpdir-metadata.driver.sh")
 test_emu(dummy.c NAME "ovniver" DRIVER "ovniver.driver.sh")
diff --git a/test/emu/ovni/thread-free-isready.c b/test/emu/ovni/thread-free-isready.c
new file mode 100644
index 0000000..72bc012
--- /dev/null
+++ b/test/emu/ovni/thread-free-isready.c
@@ -0,0 +1,27 @@
+/* Copyright (c) 2023 Barcelona Supercomputing Center (BSC)
+ * SPDX-License-Identifier: GPL-3.0-or-later */
+
+#include <ovni.h>
+#include "instr.h"
+
+/* Check the behavior of ovni_thread_isready(), which should only be 1
+ * after ovni_thread_init() and before ovni_thread_free(). */
+
+int
+main(void)
+{
+	if (ovni_thread_isready())
+		die("thread must not be ready before init");
+
+	instr_start(0, 1);
+
+	if (!ovni_thread_isready())
+		die("thread must be ready after init");
+
+	instr_end();
+
+	if (ovni_thread_isready())
+		die("thread must not be ready after free");
+
+	return 0;
+}