On Wed, 28 Feb 2018 12:14:58 +0000 Mark Rutland <mark.rutl...@arm.com> wrote:
> KASAN splats indicate that in some cases we free a live mm, then > continue to access it, with potentially disastrous results. This is > likely due to a mismatched mmdrop() somewhere in the kernel, but so far > the culprit remains elusive. > > Let's have __mmdrop() verify that the mm isn't live for the current > task, similar to the existing check for init_mm. This way, we can catch > this class of issue earlier, and without requiring KASAN. Presumably the results usually aren't disastrous. But they will be if we go and add BUG_ON()s! Can we make this WARN_ON[_ONCE]()? We should still get the same info from testers.
