Re: fault(4)

[Kamil Rytarowski <n54%gmx.com@localhost>]

On 08.02.2020 11:47, Maxime Villard wrote:
>
> Running ATF with kASan+LOCKDEBUG+fault with {N=32 scope=GLOBAL} already
> gives
> an instant crash:
>
>     kernel diagnostic assertion "radix_tree_empty_tree_p(&pmap->pm_pvtree)"
>     failed: file ".../sys/arch/x86/x86/pmap.c"
>

There is a number of similar reports on syzbot.

> Looks like radixtree.c doesn't handle allocation failures very well
> somewhere.
>
> fault(4) seems like the kind of feature that would be useful for
> stress-testing
> and fuzzing. As you can see in the diff, its code is extremely simple.
>
> Maxime
>
> [1] https://m00nbsd.net/garbage/fault/fault.diff

This tool is a must have but I defer review to others.