Messages in this thread | | | Date | Fri, 2 Mar 2018 10:24:54 +0000 | From | Mark Rutland <> | Subject | Re: [PATCH] Detect early free of a live mm |
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On Thu, Mar 01, 2018 at 05:16:09PM -0800, Andrew Morton wrote: > On Wed, 28 Feb 2018 12:14:58 +0000 Mark Rutland <mark.rutland@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.
It seems so.
> 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.
I fuzz the kernel with panic_on_warn=1, so that's practically the same for me.
I'll respin to that effect.
Thanks, Mark.
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