Memory leak in NPN_GetURL/NPP_Write/NPP_DestroyStream calls




15 years ago
12 years ago


(Reporter: brad, Unassigned)



Windows XP

Firefox Tracking Flags

(Not tracked)





15 years ago
User-Agent:       Mozilla/5.0 (Macintosh; U; PPC Mac OS X; en-us) AppleWebKit/125.5 (KHTML, like Gecko) Safari/125.9
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; rv: 1.7.3)

Calls to NPN_GetURL (and subsequent calls to NPP_Write and NPP_DestroyStream) result in a memory 
leak approximately the size of the data returned from the requested URL.  We have modified our plugin 
software (WxScopePlugin, located at to only use those calls and not store the 
data returned from the calls in any local storage itself, yet the leak persists, pointing to a leak in the 
Mozilla/Firefox code itself.  This only occurs on the Windows build.  Firefox/MacOS X does not leak (nor 
does Safari, or Netscape 4.x for Windows, yes we still keep that around for testing).

To reproduce this, download our plugin softwware, then go to <
leak/obs_refresh.wxml>.  The map shows a single observation product that requests data every 10 
seconds (the lower threshold for our plugin).  Memory usage should rise accordingly.

We also modified our plugin locally specifically for testing by placing a single call to NPN_GetURL (which 
calls the static exported geturl function) for a URL, then repeated that NPP_GetURL call in 
NPP_DestroyStream, thus resulting in endless requests for the site, while also eliminating any of our 
own allocation methods.  If you would like a copy of this plugin, please link 

Reproducible: Always
Steps to Reproduce:
1.  Download and install WxScopePlugin (available  Manually copy 
NPWXM32.DLL from "Program Files/WxScopePlugin" to Firefox's plugins folder (version 10.1 does not 
install for Firefox)
2.  Open
3.  Observe memory usage growing.
Actual Results:  
Memory usage grew at approximately the size of the data returned from the URL requested in the map 
document linked above ( every time the plugin 
requested the file (every 10 seconds).

Expected Results:  
Memory usage should have remained constant over time.
Moving to correct Product/component.
Assignee: firefox → nobody
Severity: normal → critical
Component: General → Plug-ins
Keywords: mlk
Product: Firefox → Browser
QA Contact: firefox.general → core.plugins
Version: unspecified → Trunk
Jst, can yopu take a look at this and see if we leak in
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Last Resolved: 14 years ago
Resolution: --- → EXPIRED
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