commit c151bc30789ade22d5423b20d2c72948284bba3c
author Christopher Ferris <cferris@google.com> Tue May 01 12:59:37 2018 -0700
committer Christopher Ferris <cferris@google.com> Tue May 01 14:49:15 2018 -0700
tree 687fae810571b1147c5ccb0b5f31fb7515489537
parent 8602538a15f89f91d6994c3abfd64a274bf7ddb0

Fix nullptr dereference during sort.

Add new unit test that will crash without this fix.

Bug: 78900050

Test: Ran unit tests.
Change-Id: I73e1b89e965a7b399822c3a6f25cbc70d2d355e2

libc/malloc_debug/PointerData.cpp

diff --git a/libc/malloc_debug/PointerData.cpp b/libc/malloc_debug/PointerData.cpp
index f811a5e..85139e6 100644
--- a/libc/malloc_debug/PointerData.cpp
+++ b/libc/malloc_debug/PointerData.cpp
@@ -392,10 +392,12 @@
     FrameInfoType* b_frame = b.frame_info;
     if (a_frame == nullptr && b_frame != nullptr) {
       return false;
-    }
-    if (a_frame != nullptr && b_frame == nullptr) {
+    } else if (a_frame != nullptr && b_frame == nullptr) {
       return true;
+    } else if (a_frame == nullptr && b_frame == nullptr) {
+      return a.pointer < b.pointer;
     }
+
     // Put the pointers with longest backtrace first.
     if (a_frame->frames.size() != b_frame->frames.size()) {
       return a_frame->frames.size() > b_frame->frames.size();