So I guess you don't use any Apache licensed products at work either? Since the only reason Facebook added the PATENTS file is to keep the new BSD license in line with their old Apache license. http://www.apache.org/licenses/
Apache 2.0's license clause does not have an equivalent to "The license granted hereunder will terminate, automatically and without notice, for anyone that makes any claim (including by filing any lawsuit, assertion or
other action) alleging [...] that any right in any patent claim of Facebook is invalid or unenforceable."), which is the problematic part as it means that you can't even defend yourself if Facebook sues you.
> If You institute patent litigation against any entity (including a cross-claim or counterclaim in a lawsuit) alleging that the Work or a Contribution incorporated within the Work constitutes direct or contributory patent infringement, then any patent licenses granted to You under this License for that Work shall terminate as of the date such litigation is filed.
This seems equivalent to me, is the Facebook one broader?
That says that if you claim that the thing being licensed violates your patents, your grant to their patents covering the thing is terminated. Facebook's patent grant has that, but also invalidates the patent grant if you claim that any of their patents are invalid (which you are likely to do if Facebook sues you for violating one of their patents).
So what if Apache committed something that is infringing on your patents and you sue? Does that mean you would have to stop using that specific apache licensed software (e.g. hadoop, maven, etc)
You lose the patent grant for that specific product: e.g. if you sue someone over a patent infringement in Hadoop you lose the patent grant for Hadoop, but not Maven. This may or may not mean that you have to stop using Hadoop.
I'm not a lawyer and I'm using my best guess. But you have to be on the offensive and sue Apache to terminate their license, Facebook's license says even claiming their patents are invalid terminates the license.