[Mono-bugs] [Bug 457038] New: 64-Bit issue when calling GetBytes

[bugzilla_noreply at novell.com]

https://bugzilla.novell.com/show_bug.cgi?id=457038


           Summary: 64-Bit issue when calling GetBytes
           Product: Mono: Class Libraries
           Version: SVN
          Platform: 64bit
        OS/Version: Other
            Status: NEW
          Severity: Normal
          Priority: P5 - None
         Component: Mono.Data.Sqlite
        AssignedTo: mhabersack at novell.com
        ReportedBy: daniel at hofmannmail.ath.cx
         QAContact: mono-bugs at lists.ximian.com
          Found By: ---


I'm randomly getting a SEGFAULT, when calling SqliteReader.GetBytes on my
64-bit system. (Below is a suggested solution)
A more precise description is in my comment at
https://bugzilla.novell.com/show_bug.cgi?id=398470

Thread @1 received signal 11 at #0: 0x7f2ea684400b in memcpy+0x15b.
0x7f2ea684400b  repz movsq %ds:(%rsi),%es:(%rdi)
Process #1 created new thread @24.
Thread @21 exited.
(mdb) bt
(*) #0: 0x7f2ea684400b in memcpy+0x15b
    #1: 0x411566d8 in
System.Runtime.InteropServices.Marshal.Copy(System.IntPtr, byte[], int,
int)+0x28 at
/home/dani_nobkup/src/mono/mcs/class/corlib/System.Runtime.InteropServices/Marshal.cs:162
    #2: 0x41156514 in
Mono.Data.Sqlite.Sqlite3.GetBytes(Mono.Data.Sqlite.SqliteStatement, int, int,
byte[], int, int)+0xd4 at
/home/dani_nobkup/src/mono/mcs/class/Mono.Data.Sqlite/Mono.Data.Sqlite_2.0/SQLite3.cs:476
    #3: 0x41156427 in Mono.Data.Sqlite.SqliteDataReader.GetBytes(int, long,
byte[], int, int)+0x67 at
/home/dani_nobkup/src/mono/mcs/class/Mono.Data.Sqlite/Mono.Data.Sqlite_2.0/SQLiteDataReader.cs:344
    #4: 0x41151cac in
<EvoLab.Common.Output.DbReader/<ReadData>c__Iterator0:MoveNext ()>+0x3ec at 135
    #5: 0x4112e0cb in <EvoLab.Vis.OutputStorage:GetCachedData
(EvoLab.Vis.Model.OutputNumberElement)>+0x21b at 39
    #6: 0x4112de98 in <EvoLab.Vis.Model.RepetitionDataConfigurator:GetData
()>+0x28 at 7
[..]


That knowing, I'm pretty sure, the error lies in SQLite3.cs from
Mono.Data.Sqlite.dll, more precisely here:
   internal override long GetBytes(SqliteStatement stmt, int index, int
nDataOffset, byte[] bDest, int nStart, int nLength)
    {
      IntPtr ptr;
      int nlen;
      int nCopied = nLength;

      nlen = UnsafeNativeMethods.sqlite3_column_bytes(stmt._sqlite_stmt,
index);
      ptr = UnsafeNativeMethods.sqlite3_column_blob(stmt._sqlite_stmt, index);

      if (bDest == null) return nlen;

      if (nCopied + nStart > bDest.Length) nCopied = bDest.Length - nStart;
      if (nCopied + nDataOffset > nlen) nCopied = nlen - nDataOffset;

      if (nCopied > 0)
        Marshal.Copy((IntPtr)(ptr.ToInt32() + nDataOffset), bDest, nStart,
nCopied);
      else nCopied = 0;

      return nCopied;
    }

Changing the invocation of Marshal.Copy to ptr.ToInt64() prevented the issue
for me, but I was suggested, to use
(IntPtr)((byte*) ptr + nDataOffset)
instead.

The same issue seems to exist with System.Data.SQLite as well, but I'll leave
it to you, to report to them :)


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