If `join-thread' timeout, the thread mutex is not unlocked, resulting in
deadlock to the next call to it or deadlock of the thread itself when it
terminates.
Thus, always unlock the mutex.
Fix: #55356
* module/ice-9/threads.scm (join-thread): Always unlock thread mutex.
* test-suite/tests/threads.test (join-thread): New test to ensure the
mutex is released
---
module/ice-9/threads.scm | 4 +++-
test-suite/tests/threads.test | 13 ++++++++++++-
2 files changed, 15 insertions(+), 2 deletions(-)
diff --git a/module/ice-9/threads.scm b/module/ice-9/threads.scm
index 048d8b085..a1e43b9fa 100644
--- a/module/ice-9/threads.scm
+++ b/module/ice-9/threads.scm
@@ -204,7 +204,9 @@ terminates, unless the target @var{thread} has already
terminated."
(wait-condition-variable cv mutex timeout)
(wait-condition-variable cv mutex))
(lp))
- (else timeoutval))))))
+ (else
+ (unlock-mutex mutex)
+ timeoutval))))))
(define* (try-mutex mutex)
"Try to lock @var{mutex}. If the mutex is already locked, return
diff --git a/test-suite/tests/threads.test b/test-suite/tests/threads.test
index efdf36db2..af8c8c75b 100644
--- a/test-suite/tests/threads.test
+++ b/test-suite/tests/threads.test
@@ -332,7 +332,18 @@
(sleep 2)
(system-async-mark aproc)
(join-thread other-thread)))
- #t))
+ #t)
+
+ (pass-if "do not throw exception if trying to join after timeout"
+ (let ((other-thread (begin-thread (pause))))
+ (dynamic-wind
+ (const #f)
+ (lambda ()
+ (join-thread other-thread 1)
+ (join-thread other-thread 1)
+ #t)
+ (lambda ()
+ (cancel-thread other-thread))))))
;;
;; thread cancellation
--
2.41.0
