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From:   andrey.konovalov@linux.dev
To:     Andrew Morton <akpm@linux-foundation.org>
Cc:     Andrey Konovalov <andreyknvl@gmail.com>,
        Marco Elver <elver@google.com>,
        Alexander Potapenko <glider@google.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Andrey Ryabinin <ryabinin.a.a@gmail.com>,
        kasan-dev@googlegroups.com, Will Deacon <will@kernel.org>,
        Sami Tolvanen <samitolvanen@google.com>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org,
        Andrey Konovalov <andreyknvl@google.com>
Subject: [PATCH mm 1/2] fix for "kasan, vmalloc: only tag normal vmalloc allocations"
Date:   Wed,  2 Mar 2022 16:13:30 +0100
Message-Id: <9230ca3d3e40ffca041c133a524191fd71969a8d.1646233925.git.andreyknvl@google.com>
MIME-Version: 1.0
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From: Andrey Konovalov <andreyknvl@google.com>

Pass KASAN_VMALLOC_PROT_NORMAL to kasan_unpoison_vmalloc() in the custom
KASAN instrumentation for Shadow Call Stack, as Shadow Call Stack mappings
are not executable and thus can be poisoned.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 kernel/scs.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/kernel/scs.c b/kernel/scs.c
index b83bc9251f99..1033a76a3284 100644
--- a/kernel/scs.c
+++ b/kernel/scs.c
@@ -32,7 +32,8 @@ static void *__scs_alloc(int node)
 	for (i = 0; i < NR_CACHED_SCS; i++) {
 		s = this_cpu_xchg(scs_cache[i], NULL);
 		if (s) {
-			kasan_unpoison_vmalloc(s, SCS_SIZE, KASAN_VMALLOC_NONE);
+			kasan_unpoison_vmalloc(s, SCS_SIZE,
+					       KASAN_VMALLOC_PROT_NORMAL);
 			memset(s, 0, SCS_SIZE);
 			return s;
 		}
@@ -78,7 +79,7 @@ void scs_free(void *s)
 		if (this_cpu_cmpxchg(scs_cache[i], 0, s) == NULL)
 			return;
 
-	kasan_unpoison_vmalloc(s, SCS_SIZE, KASAN_VMALLOC_NONE);
+	kasan_unpoison_vmalloc(s, SCS_SIZE, KASAN_VMALLOC_PROT_NORMAL);
 	vfree_atomic(s);
 }
 
-- 
2.25.1