php.net |  support |  documentation |  report a bug |  advanced search |  search howto |  statistics |  random bug |  login

go to bug id or search bugs for

Bug #27992 Resource Leak
Submitted: 2004-04-14 11:41 UTC Modified: 2004-04-15 11:12 UTC
From: sean@php.net Assigned:
Status: Not a bug Package: Class/Object related
PHP Version: 4.3.6RC3 OS: Linux (any)
Private report: No CVE-ID: None
View Developer Edit
Welcome back! If you're the original bug submitter, here's where you can edit the bug or add additional notes.
If you forgot your password, you can retrieve your password here.
Password:
Status:
Package:
Bug Type:
Summary:
From: sean@php.net
New email:
PHP Version: OS:

 

 [2004-04-14 11:41 UTC] sean@php.net 
Description:
------------
See the attached code; it has been isolated from PEAR (core) and PEAR::Net_Socket.

Basically, after a certain number of iterations (Linux, PHP4.3.4 and 4.3.6RC3, likely others), PHP runs out of file resources.

Warning: fsockopen(): unable to connect to 192.168.100.51:80 in /home/sean/www/dev3/crashing_resources.php on line 51
ERROR: 24 - Too many open files

This SEEMS to be a leak (file handles are never closed?) in method_exists, get_classname or get_parent_classname, because if I remove the ShrunkenPEAR constructor (OR, the _ShrunkenPEAR method), the code does not fail.

Additionally, if I instanciate ShrunkenSocket as $sock = new ShrunkenSocket() (value instead of reference), the error is also absent.  The reason I'm using a reference: PEAR::HTTP_Request instanciates Net_Socket as such.

Also, as mentioned in a comment in the code, if I change the die to an echo, the script segfaults after ~65535 iterations (which seems like an overflow problem). 

** Note: this was originally posted to internals@ (PHP-DEV), but did not get a response.**

This COULD be a critical overflow problem (when segfaulting), but I don't know enough about the matter to declare it so.


Reproduce code:
---------------
http://sean.caedmon.net/php/crashing_resources.phps

Expected result:
----------------
(see description)

Actual result:
--------------
(see description)

Patches

Pull Requests

History

AllCommentsChangesGit/SVN commitsRelated reports
 [2004-04-14 22:34 UTC] sniper@php.net 
Why woudln't it run out of file handles when you never CLOSE the socket..?
 [2004-04-15 10:02 UTC] sean@php.net 
First, $sock should get re-allocated in each iteration, thereby forcing the former $sock (and it's ->fp) out of scope.

Second, the connect() method for $sock checks to see if it already has an allocated $fp; and if so, does an fclose.

While this example isn't practical, this problem directly affects PEAR's HTTP_Request code (but this still isn't a PEAR issue).

S
 [2004-04-15 10:05 UTC] gschlossnagle@php.net 
The segfault is a known (and I believe wont-be-fixed-in
-4) 
bug in the reference counting implementation.
 [2004-04-15 10:15 UTC] sean@php.net 
Segfault: understandable
My real concern is that it seems resources are not being released in this context.

65k is a big number (segfault).
1k not so much (warning; unable to open resource).

S
 [2004-04-15 10:34 UTC] gschlossnagle@php.net 
Hi.  This isn't a bug.  In your constructor, you stick a 
reference to $this in $_PEAR_destructor_object_list.  
This gives the object a refcount of 2, so it isn't 
destructed when it falls out of scope.  This is expected 
behavior here.
 [2004-04-15 11:12 UTC] sean@php.net 
Ah, now that you point that out, it's clear. Thank you. This is why I posted to internals@, first.

Agreed. Bogus.

S
 
PHP Copyright © 2001-2024 The PHP Group
All rights reserved. 		Last updated: Sun Nov 24 16:01:31 2024 UTC