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Detect false-positive ANRs report and prevent ANR watchdog from sending them #66

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Merged
konraddysput merged 3 commits into from
Mar 15, 2021
Merged

Detect false-positive ANRs report and prevent ANR watchdog from sending them #66

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c9ba4da
Detect false-positive ANRs report and prevent ANR watchdog from sendi…
konraddysput Mar 9, 2021
f75540c
Fixed typos + better documentation - added Samy's advices
konraddysput Mar 9, 2021
5ace489
Merge branch 'release/3.4.0' into bugfix/false-positive-anr
konraddysput Mar 15, 2021
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6 changes: 5 additions & 1 deletion Runtime/BacktraceClient.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -442,7 +442,6 @@ private void OnDestroy()
Application.lowMemory -= HandleLowMemory;
_nativeClient?.Disable();
#endif

}

/// <summary>
Expand Down Expand Up @@ -725,6 +724,11 @@ private void CaptureUnityMessages()
}
}

internal void OnApplicationPause(bool pause)
{
_nativeClient?.PauseAnrThread(pause);
}

internal void HandleUnityBackgroundException(string message, string stackTrace, LogType type)
{
// validate if a message is from main thread
Expand Down
82 changes: 56 additions & 26 deletions Runtime/Native/Android/NativeClient.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -16,7 +16,20 @@ namespace Backtrace.Unity.Runtime.Native.Android
internal class NativeClient : INativeClient
{
// Last Backtrace client update time
internal float _lastUpdateTime;
volatile internal float _lastUpdateTime;

/// <summary>
/// Determine if the ANR background thread should be disabled or not
/// for some period of time.
/// This option will be used by the native client implementation
/// once application goes to background/foreground
/// </summary>
volatile internal bool _preventAnr = false;

/// <summary>
/// Determine if ANR thread should exit
/// </summary>
volatile internal bool _stopAnr = false;

private Thread _anrThread;

Expand Down Expand Up @@ -301,42 +314,50 @@ public void HandleAnr(string gameObjectName, string callbackName)
_anrThread = new Thread(() =>
{
float lastUpdatedCache = 0;
while (true)
while (_anrThread.IsAlive && _stopAnr == false)
{
if (lastUpdatedCache == 0)
if (!_preventAnr)
{
lastUpdatedCache = _lastUpdateTime;
}
else if (lastUpdatedCache == _lastUpdateTime)
{
if (!reported)
if (lastUpdatedCache == 0)
{

reported = true;
if (AndroidJNI.AttachCurrentThread() == 0)
lastUpdatedCache = _lastUpdateTime;
}
else if (lastUpdatedCache == _lastUpdateTime)
{
if (!reported)
{
// set temporary attribute to "Hang"
AddAttribute(
AndroidJNI.NewStringUTF("error.type"),
AndroidJNI.NewStringUTF("Hang"));

NativeReport(AndroidJNI.NewStringUTF("ANRException: Blocked thread detected."));
// update error.type attribute in case when crash happen
SetAttribute("error.type", "Crash");

reported = true;
if (AndroidJNI.AttachCurrentThread() == 0)
{
// set temporary attribute to "Hang"
AddAttribute(
AndroidJNI.NewStringUTF("error.type"),
AndroidJNI.NewStringUTF("Hang"));

NativeReport(AndroidJNI.NewStringUTF("ANRException: Blocked thread detected."));
// update error.type attribute in case when crash happen
SetAttribute("error.type", "Crash");
}
}
}
else
{
reported = false;
}

lastUpdatedCache = _lastUpdateTime;
}
else
else if (lastUpdatedCache != 0)
{
reported = false;
// make sure when ANR happened just after going to foreground
// we won't false positive ANR report
lastUpdatedCache = 0;
}

lastUpdatedCache = _lastUpdateTime;
Thread.Sleep(5000);

}
});

_anrThread.IsBackground = true;
_anrThread.Start();
}

Expand Down Expand Up @@ -389,8 +410,17 @@ public void Disable()
{
if (_anrThread != null)
{
_anrThread.Abort();
_stopAnr = true;
}
}

/// <summary>
/// Pause ANR detection
/// </summary>
/// <param name="stopAnr">True - if native client should pause ANR detection"</param>
public void PauseAnrThread(bool stopAnr)
{
_preventAnr = stopAnr;
}
}
}
6 changes: 6 additions & 0 deletions Runtime/Native/INativeClient.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -40,5 +40,11 @@ internal interface INativeClient
/// Disable native integration
/// </summary>
void Disable();

/// <summary>
/// Pause ANR thread
/// </summary>
/// <param name="state">True if should pause, otherwise false.</param>
void PauseAnrThread(bool state);
}
}
72 changes: 52 additions & 20 deletions Runtime/Native/iOS/NativeClient.cs
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -16,7 +16,20 @@ namespace Backtrace.Unity.Runtime.Native.iOS
internal class NativeClient : INativeClient
{
// Last Backtrace client update time
internal float _lastUpdateTime;
volatile internal float _lastUpdateTime;

/// <summary>
/// Determine if the ANR background thread should be disabled or not
/// for some period of time.
/// This option will be used by the native client implementation
/// once application goes to background/foreground
/// </summary>
volatile internal bool _preventAnr = false;

/// <summary>
/// Determine if ANR thread should exit
/// </summary>
volatile internal bool _stopAnr = false;

private Thread _anrThread;

Expand Down Expand Up @@ -139,35 +152,45 @@ public void HandleAnr(string gameObjectName, string callbackName)
_anrThread = new Thread(() =>
{
float lastUpdatedCache = 0;
while (true)
while (_anrThread.IsAlive && _stopAnr == false)
{
if (lastUpdatedCache == 0)
if (!_preventAnr)
{
lastUpdatedCache = _lastUpdateTime;
}
else if (lastUpdatedCache == _lastUpdateTime)
{
if (!reported)
if (lastUpdatedCache == 0)
{
// set temporary attribute to "Hang"
SetAttribute("error.type", "Hang");
NativeReport("ANRException: Blocked thread detected.");
// update error.type attribute in case when crash happen
SetAttribute("error.type", "Crash");
reported = true;
lastUpdatedCache = _lastUpdateTime;
}
else if (lastUpdatedCache == _lastUpdateTime)
{
if (!reported)
{
// set temporary attribute to "Hang"
SetAttribute("error.type", "Hang");
NativeReport("ANRException: Blocked thread detected.");
// update error.type attribute in case when crash happen
SetAttribute("error.type", "Crash");
reported = true;
}
}
else
{
reported = false;
}


lastUpdatedCache = _lastUpdateTime;
}
else
else if (lastUpdatedCache != 0)
{
reported = false;
// make sure when ANR happened just after going to foreground
// we won't false positive ANR report
lastUpdatedCache = 0;
}

lastUpdatedCache = _lastUpdateTime;
Thread.Sleep(5000);

}
});

_anrThread.IsBackground = true;
_anrThread.Start();
}

Expand Down Expand Up @@ -228,9 +251,18 @@ public void Disable()
{
if (_anrThread != null)
{
_anrThread.Abort();
_stopAnr = true;
}
}

/// <summary>
/// Pause ANR detection
/// </summary>
/// <param name="stopAnr">True - if native client should pause ANR detection"</param>
public void PauseAnrThread(bool stopAnr)
{
_preventAnr = stopAnr;
}
}
}
#endif