On 9/7/20 6:40 AM, Marco Elver wrote: > +The most important parameter is KFENCE's sample interval, which can be set via > +the kernel boot parameter ``kfence.sample_interval`` in milliseconds. The > +sample interval determines the frequency with which heap allocations will be > +guarded by KFENCE. The default is configurable via the Kconfig option > +``CONFIG_KFENCE_SAMPLE_INTERVAL``. Setting ``kfence.sample_interval=0`` > +disables KFENCE. > + > +With the Kconfig option ``CONFIG_KFENCE_NUM_OBJECTS`` (default 255), the number > +of available guarded objects can be controlled. Each object requires 2 pages, > +one for the object itself and the other one used as a guard page; object pages > +are interleaved with guard pages, and every object page is therefore surrounded > +by two guard pages. Is it hard to make these both tunable at runtime? It would be nice if I hit a KFENCE error on a system to bump up the number of objects and turn up the frequency of guarded objects to try to hit it again. That would be a really nice feature for development environments. It would also be nice to have a counter somewhere (/proc/vmstat?) to explicitly say how many pages are currently being used. I didn't mention it elsewhere, but this work looks really nice. It has very little impact on the core kernel and looks like a very nice tool to have in the toolbox. I don't see any major reasons we wouldn't want to merge after our typical bikeshedding. :)
