[Bug 19561] New: Very large memory leak when doing overlapped reads

http://bugs.winehq.org/show_bug.cgi?id=19561

Summary: Very large memory leak when doing overlapped reads
           Product: Wine
           Version: 1.1.26
          Platform: PC
        OS/Version: Linux
            Status: UNCONFIRMED
          Severity: major
          Priority: P2
         Component: wineserver
        AssignedTo: [e-mail]
        ReportedBy: [e-mail]

Created an attachment (id=22796)
 --> (http://bugs.winehq.org/attachment.cgi?id=22796)
Program compiled and ready to run using mingw

WINE is buffering serial ports which is in conflict with using overlapped
reads. Additionally, when using overlapped reads on a serial port, there is a
large memory leak. Every time we receive a block of data on the port, (say 800
bytes in our case,) wineserver allocates many pages on the heap and does not
free them afterwards. We are seeing as many as 21 pages lost to the heap every
time we read a small block of data.

My company is creating a Monitor & Control product that works through serial
ports, and we want it to be able to run on Linux netbooks (using USB to serial
port adapters.) This memory leak is the only thing holding us up. The memory
leak is too large for us to recommend to customers that our application can be
used on Linux platforms using WINE.

We are including an attachment for a small program that captures the leak. The
problem is a result of our call to readfile() in the do-while loop. It is using
the overlappedRead feature. Every time this Win32 function call is made, 84K
bytes disappears forever.

-Ron F.