You are able to see all the stack trace by changing the reg file.

You can follow the hints in the warning and set the following registry key as this will ensure that the stack trace of the allocation of the SPRequest object is preserved in memory and added to the 8l1n ULS log entry:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Shared Tools\Web Server Extensions\HeapSettings

        SPRequestStackTrace = 1

In the log file, the one you really need pay attention to is

05/01/2007 12:58:47.31                w3wp.exe (0x105C)                                      0x09A8 Windows SharePoint Services                   General                               8l1n       High       An SPRequest object was not disposed before the end of this thread.  To avoid wasting system resources, dispose of this object or its parent (such as an SPSite or SPWeb) as soon as you are done using it.  This object will now be disposed.  Allocation Id: {5BFFCA4B-3B91-45BF-98CD-0BB508BE30EE} To determine where this object was allocated, create a registry key at HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Shared Tools\Web Server Extensions\HeapSettings. Then create a new DWORD named SPRequestStackTrace with the value 1 under this key.

For more details please read this blog