commit cd4c724043bb6ce562fdb02bb980fde548233353
author wendy lin <wendy.lin@mediatek.com> Wed Jun 12 10:37:11 2019 +0800
committer Andy Hung <hunga@google.com> Tue Apr 07 16:51:43 2020 +0000
tree 2ffd0d41480cbc148fb07d443455b54c791fc4d0
parent 39ec5a7accf61d89a41908999bc789d5c8d0e3d3

fix audioflinger integer multiplication overflow

when underrun duration is over 3 sec, overflow happens
for multiplication of nsec=sec*1000000000. Use correct format transform
to solve it.

Bug: 135075416
Test: run MTBF test

Change-Id: I0a09ca41f2fad055ce0cfa18f936131b7a630f52

services/audioflinger/FastThread.cpp

diff --git a/services/audioflinger/FastThread.cpp b/services/audioflinger/FastThread.cpp
index dc15487..3446dc7 100644
--- a/services/audioflinger/FastThread.cpp
+++ b/services/audioflinger/FastThread.cpp
@@ -305,7 +305,7 @@
                     // compute the delta value of clock_gettime(CLOCK_MONOTONIC)
                     uint32_t monotonicNs = nsec;
                     if (sec > 0 && sec < 4) {
-                        monotonicNs += sec * 1000000000;
+                        monotonicNs += sec * 1000000000U; // unsigned to prevent signed overflow.
                     }
                     // compute raw CPU load = delta value of clock_gettime(CLOCK_THREAD_CPUTIME_ID)
                     uint32_t loadNs = 0;
@@ -321,7 +321,7 @@
                             }
                             loadNs = nsec;
                             if (sec > 0 && sec < 4) {
-                                loadNs += sec * 1000000000;
+                                loadNs += sec * 1000000000U; // unsigned to prevent signed overflow.
                             }
                         } else {
                             // first time through the loop