On Thu, Aug 27, 2020 at 11:52 AM Vincenzo Frascino
[off-list ref] wrote:

Hi Andrey,

On 8/27/20 9:04 AM, Catalin Marinas wrote:

quoted

On Fri, Aug 14, 2020 at 07:27:01PM +0200, Andrey Konovalov wrote:

quoted

Software tag-based KASAN provides its own tag checking machinery that
can conflict with MTE. Don't allow enabling software tag-based KASAN
when MTE is enabled.

Signed-off-by: Andrey Konovalov <redacted>
---
 lib/Kconfig.kasan | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan
index b4cf6c519d71..e500c18cbe79 100644
--- a/lib/Kconfig.kasan
+++ b/lib/Kconfig.kasan

@@ -69,6 +69,7 @@ config KASAN_GENERIC
 config KASAN_SW_TAGS
     bool "Software tag-based mode"
     depends on HAVE_ARCH_KASAN_SW_TAGS && CC_HAS_KASAN_SW_TAGS
+    depends on !ARM64_MTE

I think that's better as:

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 10cf81d70657..736c32bd8905 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig

@@ -131,7 +131,7 @@ config ARM64
      select HAVE_ARCH_JUMP_LABEL
      select HAVE_ARCH_JUMP_LABEL_RELATIVE
      select HAVE_ARCH_KASAN if !(ARM64_16K_PAGES && ARM64_VA_BITS_48)
-     select HAVE_ARCH_KASAN_SW_TAGS if HAVE_ARCH_KASAN
+     select HAVE_ARCH_KASAN_SW_TAGS if HAVE_ARCH_KASAN && !ARM64_MTE
      select HAVE_ARCH_KGDB
      select HAVE_ARCH_MMAP_RND_BITS
      select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT

I agree with Catalin here, "select HAVE_ARCH_KASAN_SW_TAGS if HAVE_ARCH_KASAN &&
!ARM64_MTE" should be sufficient.

Sounds good, will do in v2, thanks!

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