erts: Fix segfaulting crashdump writing

Crashdumps initiated by out-of-memory on spawn could cause the beam
to segfault during crashdump writing due to invalid pointers.

The pointers are invalid since the process creation never finished.
This commit remedies this problem by removing the process from
crashdump printout.

2 files changed, 5 insertions, 2 deletions

diff --git a/erts/emulator/beam/break.c b/erts/emulator/beam/break.c
index ad9a89b642..99604fa3bc 100644
--- a/erts/emulator/beam/break.c
+++ b/erts/emulator/beam/break.c
@@ -76,7 +76,10 @@ process_info(int to, void *to_arg)
     for (i = 0; i < max; i++) {
 	Process *p = erts_pix2proc(i);
 	if (p && p->i != ENULL) {
-	    if (!ERTS_PROC_IS_EXITING(p))
+	    /* Do not include processes with no heap,
+	     * they are most likely just created and has invalid data
+	     */
+	    if (!ERTS_PROC_IS_EXITING(p) && p->heap != NULL)
 		print_process_info(to, to_arg, p);
 	}
     }
diff --git a/erts/emulator/beam/erl_process.c b/erts/emulator/beam/erl_process.c
index 434d5ca147..5cfaf1b5ee 100644
--- a/erts/emulator/beam/erl_process.c
+++ b/erts/emulator/beam/erl_process.c
@@ -7471,6 +7471,7 @@ alloc_process(ErtsRunQueue *rq, erts_aint32_t state)
     
     p->approx_started = erts_get_approx_time();
     p->rcount = 0;
+    p->heap = NULL;
 
 
     ASSERT(p == (Process *) (erts_ptab_pix2intptr_nob(
@@ -7583,7 +7584,6 @@ erl_create_process(Process* parent, /* Parent of process (default group leader).
     hipe_init_process_smp(&p->hipe_smp);
 #endif
 #endif
-
     p->heap = (Eterm *) ERTS_HEAP_ALLOC(ERTS_ALC_T_HEAP, sizeof(Eterm)*sz);
     p->old_hend = p->old_htop = p->old_heap = NULL;
     p->high_water = p->heap;