address representation and KASAN

TheJH — Thu, 12 Jun 2025 13:12:45 +0000

> Most people seem to think that representation should be pairs of physical addresses and lengths, perhaps with a flag, he said.

For what it's worth, from the perpective of address-tagging-based KASAN and the (not yet upstream) SLUB-virtual security mitigation, it would be nice if the kernel (in particular on 64-bit) stayed in the kernel-virtual-address representation as much as possible and only used physical addresses when actually initiating DMA operations or such.

For example, some configurations of KASAN rely on tag bits in the upper part of an address being preserved for detection of memory safety bugs.

LWN: Comments on "Improving iov_iter"

address representation and KASAN