Get git to tell me where the offending whitespace is?

Question

During a rebase of some git branch of mine, I get a warning saying:

/path/to/repo/.git/rebase-apply/patch:21: trailing whitespace.
some text in a file here

Now, I can go grepping for that string, but - is there a way to make git tell me in which file (and maybe at which line number) it found the offending trailing whitespace?