[PATCH v2 0/2] arm64: kasan: log potential KASAN shadow aliases

[Mark Rutland]

When using KASAN_GENERIC or KASAN_SW_TAGS, many representable pointer
values (e.g. NULL) don't have a legitimate shadow address. If KASAN
instrumentation attempts to access the shadow for such pointers, it will
fault on an unusual-looking address, e.g.

| Unable to handle kernel paging request at virtual address dfff800000000001

To make this easier to debug, this series makes the arm64 fault handling
code log the corresponding memory range for potential shadow acceses,
e.g.

| Unable to handle kernel paging request at virtual address dfff800000000017
| KASAN: null-ptr-deref in range [0x00000000000000b8-0x00000000000000bf]

Since v1 [1]:
* Use kasan_non_canonical_hook()
* Drop move of kasan_shadow_to_mem()
* Update commit messages

[1] https://lore.kernel.org/r/20211202112731.3346975-1-mark.rutland@arm.com

Thanks,
Mark.

Mark Rutland (2):
  arm64: mm: use die_kernel_fault() in do_mem_abort()
  arm64: mm: log potential KASAN shadow alias

 arch/arm64/mm/fault.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

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2.30.2