Re: [PATCH v2 0/4] arm64: kasan: support CONFIG_KASAN_VMALLOC

Will Deacon
2021-01-22T19:35:07Z

On Thu, Jan 21, 2021 at 06:44:14PM +0100, Andrey Konovalov wrote:
> On Sat, Jan 9, 2021 at 11:33 AM Lecopzer Chen <lecopzer@gmail.com> wrote:
> >
> > Linux supports KAsan for VMALLOC since commit 3c5c3cfb9ef4da9
> > ("kasan: support backing vmalloc space with real shadow memory")
> >
> > Acroding to how x86 ported it [1], they early allocated p4d and pgd,
> > but in arm64 I just simulate how KAsan supports MODULES_VADDR in arm64
> > by not to populate the vmalloc area except for kimg address.
> >
> > Test environment:
> > 4G and 8G Qemu virt,
> > 39-bit VA + 4k PAGE_SIZE with 3-level page table,
> > test by lib/test_kasan.ko and lib/test_kasan_module.ko
> >
> > It also works in Kaslr with CONFIG_RANDOMIZE_MODULE_REGION_FULL
> > and randomize module region inside vmalloc area.
> >
> >
> > [1]: commit 0609ae011deb41c ("x86/kasan: support KASAN_VMALLOC")
> >
> > Signed-off-by: Lecopzer Chen <lecopzer.chen@mediatek.com>
> > Acked-by: Andrey Konovalov <andreyknvl@google.com>
> > Tested-by: Andrey Konovalov <andreyknvl@google.com>
> >
> >
> > v2 -> v1
> > 1. kasan_init.c tweak indent
> > 2. change Kconfig depends only on HAVE_ARCH_KASAN
> > 3. support randomized module region.
> >
> > v1:
> > https://lore.kernel.org/lkml/20210103171137.153834-1-lecopzer@gmail.com/
> >
> > Lecopzer Chen (4):
> > arm64: kasan: don't populate vmalloc area for CONFIG_KASAN_VMALLOC
> > arm64: kasan: abstract _text and _end to KERNEL_START/END
> > arm64: Kconfig: support CONFIG_KASAN_VMALLOC
> > arm64: kaslr: support randomized module area with KASAN_VMALLOC
> >
> > arch/arm64/Kconfig | 1 +
> > arch/arm64/kernel/kaslr.c | 18 ++++++++++--------
> > arch/arm64/kernel/module.c | 16 +++++++++-------
> > arch/arm64/mm/kasan_init.c | 29 +++++++++++++++++++++--------
> > 4 files changed, 41 insertions(+), 23 deletions(-)
> >
> > --
> > 2.25.1
> >
>
> Hi Will,
>
> Could you PTAL at the arm64 changes?

Sorry, wanted to get to this today but I ran out of time in the end. On the
list for next week!

Will