race condition fix: block all signals before decrementing thread count

[musl] / src / thread / pthread_create.c

diff --git a/src/thread/pthread_create.c b/src/thread/pthread_create.c
index b6c475d..c73c521 100644 (file)
--- a/src/thread/pthread_create.c
+++ b/src/thread/pthread_create.c
@@ -10,9 +10,6 @@ void __pthread_unwind_next(struct __ptcb *cb)
        self = pthread_self();
        if (self->cancel) self->result = PTHREAD_CANCELLED;
 
-       if (!a_fetch_add(&libc.threads_minus_1, -1))
-               exit(0);
-
        LOCK(&self->exitlock);
 
        not_finished = self->tsd_used;
@@ -28,6 +25,11 @@ void __pthread_unwind_next(struct __ptcb *cb)
                }
        }
 
+       syscall4(__NR_sigprocmask, SIG_BLOCK, (long)(uint64_t[1]){-1}, 0, 8);
+
+       if (!a_fetch_add(&libc.threads_minus_1, -1))
+               exit(0);
+
        if (self->detached && self->map_base)
                __unmapself(self->map_base, self->map_size);