[PATCH] kasan: fix KASAN_STACK dependency for HW_TAGS

[Andrey Konovalov]

There's a runtime failure when running HW_TAGS-enabled kernel built with
GCC on hardware that doesn't support MTE. GCC-built kernels always have
CONFIG_KASAN_STACK enabled, even though stack instrumentation isn't
supported by HW_TAGS. Having that config enabled causes KASAN to issue
MTE-only instructions to unpoison kernel stacks, which causes the failure.

Fix the issue by disallowing CONFIG_KASAN_STACK when HW_TAGS is used.

(The commit that introduced CONFIG_KASAN_HW_TAGS specified proper
 dependency for CONFIG_KASAN_STACK_ENABLE but not for CONFIG_KASAN_STACK.)

Fixes: 6a63a63ff1ac ("kasan: introduce CONFIG_KASAN_HW_TAGS")
Cc: stable at vger.kernel.org
Reported-by: Catalin Marinas <catalin.marinas at arm.com>
Signed-off-by: Andrey Konovalov <andreyknvl at google.com>
---
 lib/Kconfig.kasan | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan
index 624ae1df7984..fba9909e31b7 100644
--- a/lib/Kconfig.kasan
+++ b/lib/Kconfig.kasan
@@ -156,6 +156,7 @@ config KASAN_STACK_ENABLE
 
 config KASAN_STACK
 	int
+	depends on KASAN_GENERIC || KASAN_SW_TAGS
 	default 1 if KASAN_STACK_ENABLE || CC_IS_GCC
 	default 0
 
-- 
2.30.1.766.gb4fecdf3b7-goog