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Date:   Tue, 10 Nov 2020 23:20:09 +0100
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Subject: [PATCH v2 05/20] kasan: allow VMAP_STACK for HW_TAGS mode
From:   Andrey Konovalov <andreyknvl@google.com>
To:     Dmitry Vyukov <dvyukov@google.com>,
        Alexander Potapenko <glider@google.com>,
        Marco Elver <elver@google.com>
Cc:     Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        Evgenii Stepanov <eugenis@google.com>,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Branislav Rankov <Branislav.Rankov@arm.com>,
        Kevin Brodsky <kevin.brodsky@arm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        kasan-dev@googlegroups.com, linux-arm-kernel@lists.infradead.org,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        Andrey Konovalov <andreyknvl@google.com>
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Precedence: bulk

Even though hardware tag-based mode currently doesn't support checking
vmalloc allocations, it doesn't use shadow memory and works with
VMAP_STACK as is. Change VMAP_STACK definition accordingly.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Link: https://linux-review.googlesource.com/id/I3552cbc12321dec82cd7372676e9372a2eb452ac
---
 arch/Kconfig | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/Kconfig b/arch/Kconfig
index 56b6ccc0e32d..7e7d14fae568 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -914,16 +914,16 @@ config VMAP_STACK
 	default y
 	bool "Use a virtually-mapped stack"
 	depends on HAVE_ARCH_VMAP_STACK
-	depends on !KASAN || KASAN_VMALLOC
+	depends on !KASAN || KASAN_HW_TAGS || KASAN_VMALLOC
 	help
 	  Enable this if you want the use virtually-mapped kernel stacks
 	  with guard pages.  This causes kernel stack overflows to be
 	  caught immediately rather than causing difficult-to-diagnose
 	  corruption.
 
-	  To use this with KASAN, the architecture must support backing
-	  virtual mappings with real shadow memory, and KASAN_VMALLOC must
-	  be enabled.
+	  To use this with software KASAN modes, the architecture must support
+	  backing virtual mappings with real shadow memory, and KASAN_VMALLOC
+	  must be enabled.
 
 config ARCH_OPTIONAL_KERNEL_RWX
 	def_bool n
-- 
2.29.2.222.g5d2a92d10f8-goog