diff options
| author | xshu <xshu@google.com> | 2019-12-02 14:39:55 -0800 |
|---|---|---|
| committer | Oscar Shu <xshu@google.com> | 2019-12-04 18:25:58 +0000 |
| commit | b113e7f7d5b3e3d64f6bcb98de29c1a331008118 (patch) | |
| tree | 730119fc2d039cc6fe719d389949d508c4fb8fc0 | |
| parent | 2674f15734493eebb98528982908e398255d9e4e (diff) | |
Fix race in StaEvents metrics collection
A race is happening because one part of StaEventList modification is
current unprotected, and we have 2 different threads that trigger
StaEventList modifications:
- Thread 1: Binder thread -> dump() -> clearing StaEventList
- Thread 2: WifiLooper -> addStaEvent() -> may result in removing first
element if StaEventList if 'full'
Bug: 145673220
Test: atest FrameworksWifiTests
Change-Id: Id390bae9a9a661900073195fd1224106a03273ee
Merged-In: Id390bae9a9a661900073195fd1224106a03273ee
(cherry picked from commit df3b786149d9a86fdc247ec9cc7910e6b98de1cf)
| -rw-r--r-- | service/java/com/android/server/wifi/WifiMetrics.java | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/service/java/com/android/server/wifi/WifiMetrics.java b/service/java/com/android/server/wifi/WifiMetrics.java index 2e9e34c07..7578d3723 100644 --- a/service/java/com/android/server/wifi/WifiMetrics.java +++ b/service/java/com/android/server/wifi/WifiMetrics.java @@ -3791,9 +3791,11 @@ public class WifiMetrics { mLastScore = -1; mLastWifiUsabilityScore = -1; mLastPredictionHorizonSec = -1; - mStaEventList.add(new StaEventWithTime(staEvent, mClock.getWallClockMillis())); - // Prune StaEventList if it gets too long - if (mStaEventList.size() > MAX_STA_EVENTS) mStaEventList.remove(); + synchronized (mLock) { + mStaEventList.add(new StaEventWithTime(staEvent, mClock.getWallClockMillis())); + // Prune StaEventList if it gets too long + if (mStaEventList.size() > MAX_STA_EVENTS) mStaEventList.remove(); + } } private ConfigInfo createConfigInfo(WifiConfiguration config) { |