Experienced the same issue:

CentOS 5.4
PHP 5.2.10
Memcache Client 3.0.4
Memcached 1.2.8

Apache module as well.

Can you try using trunk or the NON_BLOCKING_IO branch please? I can't reproduce it using any of them.

We experience the same problem - spawn-fcgi workers die with 
SIGSEGV with pecl-memcache 3.0.4 when one of two memcached 
servers is down. With 3.0.1 no SIGSEGVs.

p.s. PHP 5.3.2, FreeBSD 8.0-STABLE i386

I think I am also experiencing a variation of this issue. Particularly with the session save handler.

PHP will generate the warning: "Failed to write session data (memcache). Please verify that the current setting of session.save_path is correct"

Usually the apache log will have a child process segfault around the same time. 

In the session save path, I have 4 servers listed, with the most weight given to the localhost.

The errors occur randomly, and for the most part only affects a single request in a given period. I have started to see an increase in errors of late, from a couple per week to several per day.

I can reproduce SegFault with two unreachable Servers with 
multi get:

Command line:

php -r '$m = new Memcache(); $m->addServer("s1"); $m-
>addServer("s2"); $m->get(array("k1","k2"));'

Output:

PHP Warning:  MemcachePool::get(): php_network_getaddresses: 
getaddrinfo failed: Name or service not known in Command 
line code on line 1
PHP Notice:  MemcachePool::get(): Server s2 (tcp 11211, udp 
0) failed with: php_network_getaddresses: getaddrinfo 
failed: Name or service not known (0) in Command line code 
on line 1
PHP Warning:  MemcachePool::get(): php_network_getaddresses: 
getaddrinfo failed: Name or service not known in Command 
line code on line 1
PHP Notice:  MemcachePool::get(): Server s1 (tcp 11211, udp 
0) failed with: php_network_getaddresses: getaddrinfo 
failed: Name or service not known (0) in Command line code 
on line 1
Speicherzugriffsfehler


$ php -r '$m = new Memcache(); $m->addServer("s1"); $m-
>addServer("s2"); $m->get(array("k1","k2"));'
PHP Warning:  MemcachePool::get(): php_network_getaddresses: 
getaddrinfo failed: Name or service not known in Command 
line code on line 1
PHP Notice:  MemcachePool::get(): Server s2 (tcp 11211, udp 
0) failed with: php_network_getaddresses: getaddrinfo 
failed: Name or service not known (0) in Command line code 
on line 1
PHP Warning:  MemcachePool::get(): php_network_getaddresses: 
getaddrinfo failed: Name or service not known in Command 
line code on line 1
PHP Notice:  MemcachePool::get(): Server s1 (tcp 11211, udp 
0) failed with: php_network_getaddresses: getaddrinfo 
failed: Name or service not known (0) in Command line code 
on line 1
Speicherzugriffsfehler
$ php --version
PHP 5.3.3-6 with Suhosin-Patch (cli) (built: Dec  7 2010 
12:47:03) 
Copyright (c) 1997-2009 The PHP Group
Zend Engine v2.3.0, Copyright (c) 1998-2010 Zend 
Technologies
$ dpkg -l php5* |grep ^ii
ii  php5-cli                                     5.3.3-6                                
command-line interpreter for the php5 scripting language
ii  php5-common                                  5.3.3-6                                
Common files for packages built from the php5 source
ii  php5-ldap                                    5.3.3-6                                
LDAP module for php5
ii  php5-memcache                                3.0.4-4                                
memcache extension module for PHP5

I can also reproduce this.

OS: FreeBSD 8.2 and 9-CURRENT
Webserver: nginx 0.8.54
Php: 5.3.5 (running as fpm)
pecl-memcache: 3.0.5

I have 2 memcache servers in session.save_path, as soon as one goes down, the fpm worker processes die:

Mar 04 16:30:30.374057 [WARNING] [pool www] child 18530 exited on signal 10 (SIGBUS) after 35.872334 seconds from start
Mar 04 16:30:30.374375 [NOTICE] [pool www] child 18569 started
Mar 04 16:30:30.416024 [WARNING] [pool www] child 18531 exited on signal 10 (SIGBUS) after 35.913949 seconds from start
Mar 04 16:30:30.416387 [NOTICE] [pool www] child 18570 started
Mar 04 16:30:30.462851 [WARNING] [pool www] child 18532 exited on signal 10 (SIGBUS) after 35.960400 seconds from start
Mar 04 16:30:30.463158 [NOTICE] [pool www] child 18571 started

Versions 3.0.1 to 3.0.3 work, 3.0.4 and 3.0.5 don't work.

Using Pada's script I can confirm this is broken in 3.0.4 and 3.0.5.  However, I do not see this breakin trunk.  Please verify this works in trunk.

Yes, you are right with trunk it does indeed work.

No feedback was provided. The bug is being suspended because
we assume that you are no longer experiencing the problem.
If this is not the case and you are able to provide the
information that was requested earlier, please do so and
change the status of the bug back to "Open". Thank you.