Installing lxml with pip in virtualenv Ubuntu 12.10 error: command ‘gcc’ failed with exit status 4

Make sure you have enough memory. Try dmesg | tail to see if it outputs something like:

...
[3778136.277570] Out of memory: Kill process 21267 (cc1) score 557 or sacrifice child
[3778136.277587] Killed process 21267 (cc1) total-vm:365836kB, anon-rss:336228kB, file-rss:0kB