CPU spikes to 100% in an infinite While loop

[sghiassy]

I'm seeing a problem where the app locks and the CPU throttles to 100% infinitely.

Sample App

Here is a sample repo that you can download. The app is only 140 lines long, but reproduces the issue 100%: https://github.com/sghiassy/react-bug

Cause

I'm not 100% sure what the issue is, but I've tracked it down to file Layout.c's while loop on line 455.

[ide]

I believe this is a known bug :(
I don't remember the specifics off the top of my head but search the issues for "flex cpu" and I think you'll find similar issues.

[sghiassy]

Thanks for the tip @ide . I found some similar issues:

• [Layout] Navigating back to scene with flexWrap + flexDirection sends CPU to 100% #1378
• [Style] flexWrap causes CPU 100% and freezes the app #2221 (closed)
• Certain styles applied together peg CPU #824 (closed)

Its of interest to note that each of the issues reports 100% pegging in Layout.c but the cause / repo steps seem to differ.

[ide]

Interesting. Unfortunately I can't tell you when this will be fixed or whether this is a priority for Facebook but it does seem important and more data points are helpful. Thanks for your report.

[ide]

A 100% CPU bug in css-layout has been patched in 0.10 and 0.11-rc.

[browniefed]

@ide close since it's fixed.