Hi,

From the latest upstream, I find the return value of pthread_getschedparam() is wrong when syscall sched_getparam succeeds but sched_getscheduler fails. It is rare to see this situation. When it happens, pthread_getschedparam() will return r which must be 0, that means a success according to POSIX 2017 specification. It’s wrong.

Also, POSIX 2017 specification says an error number shall be returned to indicate the error. I think returning -*policy is appropriate because syscall sched_getscheduler returns an negative error code in kernel like Linux when it fails.

Here is my patch. I want to be Cc’d on replies. Thanks.

diff --git a/src/thread/pthread_getschedparam.c b/src/thread/pthread_getschedparam.c

index 1cba073d..8203d609 100644

--- a/src/thread/pthread_getschedparam.c

+++ b/src/thread/pthread_getschedparam.c

@@ -12,6 +12,9 @@ int pthread_getschedparam(pthread_t t, int *restrict policy, struct sched_param

                if (!r) {

                        *policy = __syscall(SYS_sched_getscheduler, t->tid);

                }

+               if (*policy < 0) {

+                       r = -*policy;

+               }

        }

        UNLOCK(t->killlock);

        return r;