mpid/sched: Fix issue with schedule entries list processing

Call of MPID_Sched_cb callback function can force list memory
reallocation. As a result entry point proccessed before call
can become invalid. It should be set again after callback call.
Signed-off-by: Devendar Bureddy <devendar@mellanox.com>
Signed-off-by: Igor Ivanov <Igor.Ivanov@itseez.com>
Signed-off-by: Wesley Bland <wbland@anl.gov>

src/mpid/common/sched/mpid_sched.c

@@ -217,6 +217,8 @@ static int MPIDU_Sched_start_entry(struct MPIDU_Sched *s, size_t idx, struct MPI
             MPIU_DBG_MSG_D(COMM, VERBOSE, "starting CB entry %d\n", (int) idx);
             if (e->u.cb.cb_type == MPIDU_SCHED_CB_TYPE_1) {
                 ret_errno = e->u.cb.u.cb_p(r->comm, s->tag, e->u.cb.cb_state);
+                /* Sched entries list can be reallocated inside callback */
+                e = &s->entries[idx];
                 if (unlikely(ret_errno)) {
                     if (MPIR_ERR_NONE == r->errflag) {
                         if (MPIX_ERR_PROC_FAILED == MPIR_ERR_GET_CLASS(ret_errno)) {
@@ -232,6 +234,8 @@ static int MPIDU_Sched_start_entry(struct MPIDU_Sched *s, size_t idx, struct MPI
             }
             else if (e->u.cb.cb_type == MPIDU_SCHED_CB_TYPE_2) {
                 ret_errno = e->u.cb.u.cb2_p(r->comm, s->tag, e->u.cb.cb_state, e->u.cb.cb_state2);
+                /* Sched entries list can be reallocated inside callback */
+                e = &s->entries[idx];
                 if (unlikely(ret_errno)) {
                     if (MPIR_ERR_NONE == r->errflag) {
                         if (MPIX_ERR_PROC_FAILED == MPIR_ERR_GET_CLASS(ret_errno)) {
@@ -281,6 +285,8 @@ static int MPIDU_Sched_continue(struct MPIDU_Sched *s)
 
         if (e->status == MPIDU_SCHED_ENTRY_STATUS_NOT_STARTED) {
             mpi_errno = MPIDU_Sched_start_entry(s, i, e);
+            /* Sched entries list can be reallocated inside callback */
+            e = &s->entries[i];
             if (mpi_errno) MPIU_ERR_POP(mpi_errno);
         }