Re: [GHC] #14503: Killing a thread will block if there is another process reading from a handle

27 Nov 2017


      #14503: Killing a thread will block if there is another process reading from a
handle
-------------------------------------+-------------------------------------
        Reporter:  dnadales          |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  libraries/base    |              Version:  8.0.2
      Resolution:                    |             Keywords:
Operating System:  Windows           |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------
Changes (by dnadales):

 * component:  Compiler => libraries/base


Comment:

 The problem can be easily reproduced by running these two programs in
 parallel:

 {{{#!hs
 readWithinNSecs :: IO ()
 readWithinNSecs = withSocketsDo $ do
   h <- connectTo "localhost" (PortNumber 9090)
   hSetBuffering h NoBuffering
   readerTid <- forkIO $ reader h
   threadDelay $ 2 * 10^6
   putStrLn "Killing the reader"
   killThread readerTid
   putStrLn "Reader thread killed"
   where
     reader h = do
       line <- strip <$> hGetLine h
       putStrLn $ "Got " ++ line
 }}}

 {{{#!java
 import java.net.*;
 import java.io.*;

 public class Reader {
     public static void main(String[] args) throws IOException,
 InterruptedException {

         ServerSocket serverSock = new ServerSocket(9090);

         Socket sock = serverSock.accept();

         InputStream inStream = sock.getInputStream();
         BufferedReader sockIn = new BufferedReader(new
 InputStreamReader(inStream));

         while (true) {
             Thread.sleep(1000);
             System.out.println("Trying to read something...");
             String s = sockIn.readLine();
             System.out.println("Got " + s );
         }
     }
 }
 }}}

-- 
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14503#comment:1
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