musl - musl - an implementation of the standard library for Linux-based systems

diff --git a/src/thread/synccall.c b/src/thread/synccall.c
index 648a6ad4..d58c851f 100644
--- a/src/thread/synccall.c
+++ b/src/thread/synccall.c

@@ -63,7 +63,8 @@ void __synccall(void (*func)(void *), void *ctx)

sem_init(&target_sem, 0, 0);

sem_init(&caller_sem, 0, 0);

- if (!libc.threads_minus_1) goto single_threaded;

+ if (!libc.threads_minus_1 || __syscall(SYS_gettid) != self->tid)

+ goto single_threaded;

callback = func;

context = ctx;