why System.err.println stuck at write?

Question

Does anyone know why System.err.println is stuck at write? Issue happen during monkey test, check the code, it is stuck at System.err.println(s); here is calling stack:

"main" prio=10 tid=1 Native
  | group="main" sCount=1 dsCount=0 flags=1 obj=0x12c01e18 self=0x793e45ea00
  | sysTid=14489 nice=-8 cgrp=default sched=0/0 handle=0x79c34989a8
  | state=S schedstat=( 893730957 58891353 263 ) utm=66 stm=23 core=1 HZ=100
  | stack=0x7ff175a000-0x7ff175c000 stackSize=8MB
  | held mutexes=
  kernel: __switch_to+0xa4/0xd8
  kernel: pipe_wait+0x6c/0xb8
  kernel: pipe_write+0x1dc/0x444
  kernel: new_sync_write+0xd8/0x124
  kernel: vfs_write+0x15c/0x1d0
  kernel: SyS_write+0x60/0xc0
  kernel: __sys_trace+0x4c/0x4c
  native: #00 pc 000000000007afb4  /system/lib64/libc.so (write+4)
  native: #01 pc 0000000000032e14  /system/lib64/libjavacore.so (???)
  native: #02 pc 0000000000237194  /system/framework/arm64/boot-core-libart.oat (Java_libcore_io_Linux_writeBytes__Ljava_io_FileDescriptor_2Ljava_lang_Object_2II+196)
  at libcore.io.Linux.writeBytes(Native method)
  at libcore.io.Linux.write(Linux.java:288)
  at libcore.io.BlockGuardOs.write(BlockGuardOs.java:345)
  at libcore.io.IoBridge.write(IoBridge.java:553)
  at java.io.FileOutputStream.write(FileOutputStream.java:326)
  at java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:82)
  at java.io.BufferedOutputStream.flush(BufferedOutputStream.java:140)
  - locked <0x0ee2596f> (a java.io.BufferedOutputStream)
  at java.io.PrintStream.write(PrintStream.java:505)
  - locked <0x087a167c> (a java.io.PrintStream)
  at sun.nio.cs.StreamEncoder.writeBytes(StreamEncoder.java:221)
  at sun.nio.cs.StreamEncoder.implFlushBuffer(StreamEncoder.java:291)
  at sun.nio.cs.StreamEncoder.flushBuffer(StreamEncoder.java:104)
  - locked <0x0ebd8b05> (a java.io.OutputStreamWriter)
  at java.io.OutputStreamWriter.flushBuffer(OutputStreamWriter.java:185)
  at java.io.PrintStream.write(PrintStream.java:554)
  - locked <0x087a167c> (a java.io.PrintStream)
  at java.io.PrintStream.print(PrintStream.java:698)
  at java.io.PrintStream.println(PrintStream.java:835)
  - locked <0x087a167c> (a java.io.PrintStream)
  at com.android.commands.monkey.Logger$2.println(Logger.java:37)
  at com.android.commands.monkey.Monkey.commandLineReport(Monkey.java:510)

score 0 · Accepted Answer · answered Jun 25 '18 at 08:32

0

Most likely what ever is reading System.err isn't consuming the data. Once the buffer fills up, the program will wait until there is space in the buffer to write more.

answered Jun 25 '18 at 08:32

Peter Lawrey

525,659
79
751
1,130

Thank you. From code, it is calling System.err.println(s), so is it possible that the console is reboot or unconnect which makes monkey blocked? – Judy.NiuXiaohui Jun 25 '18 at 08:38

why System.err.println stuck at write?

1 Answers1