289888 - Memory leak in mozilla\gfx\src\windows\nsImageWin.cpp: LoadLibrary is never freed, and cannot be freed.

Status: RESOLVED WONTFIX

(Core Graveyard :: GFX: Win32, defect)

Description

[Itay Perl]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.7.6) Gecko/20050317 Firefox/1.0.2
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.7.6) Gecko/20050317 Firefox/1.0.2

in file mozilla\gfx\src\windows\nsImageWin.cpp: 
1437   gAlphaBlend = (ALPHABLENDPROC)::GetProcAddress(::LoadLibrary("msimg32"),
1438          "AlphaBlend");
This causes a memory leak, because we cannot free it using FreeLibrary
(GetProcAddress is the only function which can access this HMODULE).
possible solution:

PRBool nsImageWin::CanAlphaBlend(void)
{
  static PRBool alreadyChecked = PR_FALSE;

  if (!alreadyChecked) {
    OSVERSIONINFO os;
    
    os.dwOSVersionInfoSize = sizeof(os);
    ::GetVersionEx(&os);
    // If running on Win98, disable using AlphaBlend()
    // to avoid Win98 AlphaBlend() bug
    if (VER_PLATFORM_WIN32_WINDOWS != os.dwPlatformId ||
        os.dwMajorVersion != 4 || os.dwMinorVersion != 10) {
        HMODULE hMsimg32; 
        hMsimg32 = ::LoadLibrary("msimg32");
      gAlphaBlend = (ALPHABLENDPROC)::GetProcAddress(hMsimg32,
              "AlphaBlend");
        FreeLibrary(hMsimg32)
    }
    alreadyChecked = PR_TRUE;
  }

  return gAlphaBlend != NULL;
}


Reproducible: Always

Steps to Reproduce:




Detected with BoundsChecker 7.2.0

Comment 1

[Michiel van Leeuwen (email: mvl+moz@)]

*** Bug 289891 has been marked as a duplicate of this bug. ***

Comment 2

[Christian :Biesinger (don't email me, ping me on IRC)]

>      gAlphaBlend = (ALPHABLENDPROC)::GetProcAddress(hMsimg32,
>              "AlphaBlend");
>        FreeLibrary(hMsimg32)

that won't work, since after you free the library, you have to assume that the
function pointer is invalid

Comment 3

[Itay Perl]

True.. So where can it be freed?

Comment 4

[Gervase Markham [:gerv]]

This is an automated message, with ID "auto-resolve01".

This bug has had no comments for a long time. Statistically, we have found that
bug reports that have not been confirmed by a second user after three months are
highly unlikely to be the source of a fix to the code.

While your input is very important to us, our resources are limited and so we
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Comment 5

[Gervase Markham [:gerv]]

This bug has been automatically resolved after a period of inactivity (see above
comment). If anyone thinks this is incorrect, they should feel free to reopen it.

Comment 6

[Steve England [:stevee]]

Reopening so this can get a yay/nay from someone who knows about such leaks.

Comment 7

[Daniel Veditz [:dveditz]]

Basically same leak at http://lxr.mozilla.org/mozilla/source/gfx/cairo/cairo/src/cairo-win32-surface.c#586

Comment 8

[Daniel Veditz [:dveditz]]

This isn't one to worry about. We need the library loaded as long as we're blending images, and the OS will free it when we shut down.