[PATCH mm v4 36/39] kasan: allow enabling KASAN_VMALLOC and SW/HW_TAGS

andrey.konovalov
2021-12-20T22:03:40Z

Allow enabling CONFIG_KASAN_VMALLOC with SW_TAGS and HW_TAGS KASAN
modes.

Also adjust CONFIG_KASAN_VMALLOC description:

- Mention HW_TAGS support.
- Remove unneeded internal details: they have no place in Kconfig
description and are already explained in the documentation.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
lib/Kconfig.kasan | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan
index 879757b6dd14..1f3e620188a2 100644
--- a/lib/Kconfig.kasan
+++ b/lib/Kconfig.kasan
@@ -178,17 +178,17 @@ config KASAN_TAGS_IDENTIFY
memory consumption.

config KASAN_VMALLOC
- bool "Back mappings in vmalloc space with real shadow memory"
- depends on KASAN_GENERIC && HAVE_ARCH_KASAN_VMALLOC
+ bool "Check accesses to vmalloc allocations"
+ depends on HAVE_ARCH_KASAN_VMALLOC
help
- By default, the shadow region for vmalloc space is the read-only
- zero page. This means that KASAN cannot detect errors involving
- vmalloc space.
-
- Enabling this option will hook in to vmap/vmalloc and back those
- mappings with real shadow memory allocated on demand. This allows
- for KASAN to detect more sorts of errors (and to support vmapped
- stacks), but at the cost of higher memory usage.
+ This mode makes KASAN check accesses to vmalloc allocations for
+ validity.
+
+ With software KASAN modes, checking is done for all types of vmalloc
+ allocations. Enabling this option leads to higher memory usage.
+
+ With hardware tag-based KASAN, only VM_ALLOC mappings are checked.
+ There is no additional memory usage.

config KASAN_KUNIT_TEST
tristate "KUnit-compatible tests of KASAN bug detection capabilities" if !KUNIT_ALL_TESTS
--
2.25.1