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Report From: Delphi-BCB/RTL/Delphi/RTL Exceptions [ Add a report in this area ]

Report #: 101329

Status: Open

Exception.StackInfo leaks if AcquireExceptionObject is used

Project: Delphi

Build #: 16.0.4316.44803

Version: 16.2

Submitted By: Andreas Hausladen

Report Type: Minor failure / Design problem

Date Reported: 11/25/2011 1:37:19 PM

Severity: Infrequently encountered problem

Last Updated: 3/20/2012 2:24:39 AM

Platform: All platforms

Internal Tracking #: 288975

Resolution: None (Resolution Comments)

Resolved in Build: : None

Duplicate of: None

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Description

Exceptions leak memory for the StackInfo if an stack info provider is installed (Exception.GetExceptionStackInfoProc) and the AcquireExceptionObject function is used. This is because the GetExceptionStackInfoProc is called when the exception is raised. But if the exception is raised again after a call to AcquireExceptionObject, the StackInfo field is overwritten and the value from the previous call to GetExceptionStackInfoProc is lost.

A possible fix is to skip the call to GetExceptionStackInfoProc if the StackInfo field already has a value.

This bug exists since the StackInfo was introduced.

Steps to Reproduce:

1. Open the attached project in XE2
2. Start it

Expected:
No memory leak is reported.

Actual:
It outputs "Memory leaked" and the memory manager shows the memory leak report for the string that was allocated in GetExceptionStackInfo

Workarounds

Return the already allocated StackInfo if the ExceptionRecord.ExceptObject.StackInfo is not nil.

function GetExceptionStackInfo(P: PExceptionRecord): Pointer;
begin
  if (P.ExceptObject <> nil) and (Exception(P.ExceptObject).StackInfo <> nil) then
    Result := Exception(P.ExceptObject).StackInfo
  else
    Result := AllocateStackInfo...;
end;

Attachment

ExceptionStackInfoMemLeak.zip

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