OK, so you are a site builder or a privileged role building a view. In the preview you see a certain result set, but regular and/or anonymous users see only subset of those results or no results at all.
"[notice] child pid 45617 exit signal Segmentation fault (11)":
This is usually the start of a very bad day. Since a segfault is a low-level error in native machine code (in this case the PHP interpreter), many typical debugging techniques don't apply. Today I decided to try something new:
Have you ever chased a bug down a rabbit hole and spent a few hours down there only to come back up for air thinking "why, oh why does the bug taunt me"? If you have then you know that every clue can count. Any given clue can send you on the shortest path from A to B, or it can send you spiraling. When looking for clues always remember that your code is not the only place to look. Sometimes valuable hints can be gained from the database as well.
I recently helped a friend with a couple bugs they were fixing on a mobile site, and suddenly realized that there is a good basic list of tools that folks should have in their frontend dev kit. Robbie wrote a little while ago about some of the front end (CSS/CSS3) tools he uses, so I thought I'd add to the list, and lean a bit more toward debugging.