Bug #1634 "operator new" in my_new wastes memory

• Submitted: 23 Oct 2003 2:03
• Modified: 30 Oct 2003 1:30
• Reporter: Marko Mäkelä
• Status: Closed
• Category: MySQL Server
• Severity: S3 (Non-critical)
• Version: 4.0 and 4.1
• OS: Linux (GNU/Linux)
• Assigned to: Konstantin Osipov
• CPU Architecture: Any

[23 Oct 2003 2:03] Marko Mäkelä

Description:
Here's a snip from mysys/my_new.cc.

void *operator new (size_t sz)
{
  return (void *) malloc (sz ? sz+1 : sz);
}

void *operator new[] (size_t sz)
{
  return (void *) malloc (sz ? sz+1 : sz);
}

How to repeat:
Compile the code with -DUSE_MYSYS_NEW.  Try to allocate an object of size 0.  The argument of the malloc function will evaluate to 0, and the intended work-around for allocating zero bytes will fail.  Try to allocate an object of any other size.  The argument of malloc will evaluate to sz+1, wasting at least one byte of memory.

Suggested fix:
I believe that the two "return" lines should be as follows:
return (void *) malloc (sz > 0 ? sz : 1);

[30 Oct 2003 1:30] Konstantin Osipov

Fixed, ChangeSet 1.1601 03/10/30 12:25:15 [e-mail]