[PATCH] ARM: mm: add imprecise abort non-deadly handler

Dave Martin Dave.Martin at arm.com
Tue Feb 11 10:43:07 EST 2014

On Mon, Feb 10, 2014 at 05:25:15PM +0000, Ben Dooks wrote:
> On 10/02/14 14:37, Dave Martin wrote:


> >"Spurious" imprecise aborts pretty much always indicate a hardware error
> >or a nasty bug somewhere.
> I need to find out where the one we are catching is coming from in our
> system.

Would certainly be good to know...

> >Another cause is badly implemented, buggy or malicious userspace software
> >being given more exotic mmaps that it is qualified to deal with
> >responsibly.  That's a nasty bug in the distro maintainer / system
> >administrator / vendor.
> >
> >So, I think this should be at least KERN_ERROR; maybe KERN_CRIT or above.
> >We must not encourage people to think that these aborts are somehow
> >benign.
> Ok, KERN_ERROR or KERN_CRIT sound reasonable.
> >If we really want people to fix their bugs, it may be worth considering
> >panic(), or doing this when some threshold is reached.  This may be a
> >bit harsh though, at least without some threshold.
> I was considering also firing a WARN_ON(abort_count++ > 10) or something
> similar.

Maybe WARN_ON the first such abort, and ratelimit somehow after?

Being noisy is good -- it's just killing a random, possibly-innocent task
that's not so good.


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