The patch titled
Subject: kasan, arm64: don't instrument functions that enable kasan
has been added to the -mm tree. Its filename is
kasan-arm64-dont-instrument-functions-that-enable-kasan.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/kasan-arm64-dont-instrument-functions-that-enable-kasan.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/kasan-arm64-dont-instrument-functions-that-enable-kasan.patch
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------------------------------------------------------
From: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Subject: kasan, arm64: don't instrument functions that enable kasan
This patch prepares Software Tag-Based KASAN for stack tagging support.
With stack tagging enabled, KASAN tags stack variable in each function in
its prologue. In start_kernel() stack variables get tagged before KASAN
is enabled via setup_arch()->kasan_init(). As the result the tags for
start_kernel()'s stack variables end up in the temporary shadow memory.
Later when KASAN gets enabled, switched to normal shadow, and starts
checking tags, this leads to false-positive reports, as proper tags are
missing in normal shadow.
Disable KASAN instrumentation for start_kernel(). Also disable it for
arm64's setup_arch() as a precaution (it doesn't have any stack variables
right now).
Link: http://lkml.kernel.org/r/55d432671a92e931ab8234b03dc36b14d4c21bfb.1596199677.git.andreyknvl@xxxxxxxxxx
Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Elena Petrova <lenaptr@xxxxxxxxxx>
Cc: Marco Elver <elver@xxxxxxxxxx>
Cc: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Cc: Walter Wu <walter-zh.wu@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/arm64/kernel/setup.c | 2 +-
init/main.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
--- a/arch/arm64/kernel/setup.c~kasan-arm64-dont-instrument-functions-that-enable-kasan
+++ a/arch/arm64/kernel/setup.c
@@ -276,7 +276,7 @@ arch_initcall(reserve_memblock_reserved_
u64 __cpu_logical_map[NR_CPUS] = { [0 ... NR_CPUS-1] = INVALID_HWID };
-void __init setup_arch(char **cmdline_p)
+void __init __no_sanitize_address setup_arch(char **cmdline_p)
{
init_mm.start_code = (unsigned long) _text;
init_mm.end_code = (unsigned long) _etext;
--- a/init/main.c~kasan-arm64-dont-instrument-functions-that-enable-kasan
+++ a/init/main.c
@@ -827,7 +827,7 @@ void __init __weak arch_call_rest_init(v
rest_init();
}
-asmlinkage __visible void __init start_kernel(void)
+asmlinkage __visible __no_sanitize_address void __init start_kernel(void)
{
char *command_line;
char *after_dashes;
_
Patches currently in -mm which might be from andreyknvl@xxxxxxxxxx are
kasan-dont-tag-stacks-allocated-with-pagealloc.patch
kasan-arm64-dont-instrument-functions-that-enable-kasan.patch
kasan-allow-enabling-stack-tagging-for-tag-based-mode.patch
kasan-adjust-kasan_stack_oob-for-tag-based-mode.patch
