ANR in Android 10

[prempalsingh]

Happening only on Android 10 devices. My app doesn't target Android 10 yet so doesn't seem to be an issue with Scoped Storage. About 40k reports in last week itself.

The "main" (tid=1) thread is performing disk I/O.
"main" prio=5 tid=1 Native
  | group="main" sCount=1 dsCount=0 flags=1 obj=0x72783878 self=0x7ed6810800
  | sysTid=4799 nice=0 cgrp=default sched=0/0 handle=0x7f5d862ed0
  | state=S schedstat=( 380782951 76966367 517 ) utm=25 stm=12 core=0 HZ=100
  | stack=0x7ff69b1000-0x7ff69b3000 stackSize=8192KB
  | held mutexes=
  #00  pc 00000000000c2444  /apex/com.android.runtime/lib64/bionic/libc.so (read+4)
  #01  pc 0000000000031d80  /apex/com.android.runtime/lib64/libjavacore.so (Linux_readBytes(_JNIEnv*, _jobject*, _jobject*, _jobject*, int, int)+268)
  at libcore.io.Linux.readBytes (Linux.java)
  at libcore.io.Linux.read (Linux.java:190)
  at libcore.io.ForwardingOs.read (ForwardingOs.java:177)
  at libcore.io.BlockGuardOs.read (BlockGuardOs.java:303)
  at libcore.io.ForwardingOs.read (ForwardingOs.java:177)
  at libcore.io.IoBridge.read (IoBridge.java:513)
  at java.io.FileInputStream.read (FileInputStream.java:313)
  at java.io.BufferedInputStream.read1 (BufferedInputStream.java:286)
  at java.io.BufferedInputStream.read (BufferedInputStream.java:347)
- locked <0x0e92d5a8> (a java.lang.UNIXProcess$ProcessPipeInputStream)
  at sun.nio.cs.StreamDecoder.readBytes (StreamDecoder.java:291)
  at sun.nio.cs.StreamDecoder.implRead (StreamDecoder.java:355)
  at sun.nio.cs.StreamDecoder.read (StreamDecoder.java:181)
- locked <0x098e58c1> (a java.io.InputStreamReader)
  at java.io.InputStreamReader.read (InputStreamReader.java:184)
  at java.io.Reader.read (Reader.java:100)
  at java.util.Scanner.readInput (Scanner.java:817)
  at java.util.Scanner.next (Scanner.java:1392)
  at com.scottyab.rootbeer.RootBeer.mountReader (RootBeer.java:217)
  at com.scottyab.rootbeer.RootBeer.checkForRWPaths (RootBeer.java:291)
  at com.scottyab.rootbeer.RootBeer.isRooted (RootBeer.java:44)
  at in.test.App.initialize (App.java:192)
  at in.test.App.onCreate (App.java:133)
  at android.app.Instrumentation.callApplicationOnCreate (Instrumentation.java:1236)
  at android.app.ActivityThread.handleBindApplication (ActivityThread.java:6811)
  at android.app.ActivityThread.access$1400 (ActivityThread.java:255)
  at android.app.ActivityThread$H.handleMessage (ActivityThread.java:2068)
  at android.os.Handler.dispatchMessage (Handler.java:107)
  at android.os.Looper.loop (Looper.java:230)
  at android.app.ActivityThread.main (ActivityThread.java:7741)
  at java.lang.reflect.Method.invoke (Method.java)
  at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run (RuntimeInit.java:508)
  at com.android.internal.os.ZygoteInit.main (ZygoteInit.java:1034)

[stealthcopter]

@prempalsingh I think this is an issue with using RootBeer on the UI thread rather than an issue with scoped storage. Can you make sure that you're calling isRooted() in a background thread?

[prempalsingh]

@stealthcopter I agree, that was my first thought too but what's strange is that it's only occurring on Android 10 devices. Possible this could be some behaviour change introduced in Android 10?

[stealthcopter]

Yes, this is because disk io was allowed on the ui thread (but not recommended) on older android versions but now they are enforcing it be on a background thread

[prempalsingh]

Thanks, can close this issue. I think it would be great to mention in the README that isRooted() does disk I/O and should be called on a background thread. I've created #150. Let me know if you want any changes.

[stealthcopter]

Thanks for the update and the PR @prempalsingh much appreciated!