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, linux-mm@kvack.org,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        linux-arm-kernel@lists.infradead.org,
        Peter Collingbourne <pcc@google.com>,
        Evgenii Stepanov <eugenis@google.com>,
        linux-kernel@vger.kernel.org,
        Andrey Konovalov <andreyknvl@google.com>
Subject: [PATCH mm v5 33/39] kasan: mark kasan_arg_stacktrace as __initdata
Date:   Thu, 30 Dec 2021 20:14:58 +0100
Message-Id: <4ee96e054d59a2c65dace818cfa2c2e2bd1cb2ee.1640891329.git.andreyknvl@google.com>
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From: Andrey Konovalov <andreyknvl@google.com>

As kasan_arg_stacktrace is only used in __init functions, mark it as
__initdata instead of __ro_after_init to allow it be freed after boot.

The other enums for KASAN args are used in kasan_init_hw_tags_cpu(),
which is not marked as __init as a CPU can be hot-plugged after boot.
Clarify this in a comment.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Suggested-by: Marco Elver <elver@google.com>

---

Changes v1->v2:
- Add this patch.
---
 mm/kasan/hw_tags.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c
index 2e9378a4f07f..6509809dd5d8 100644
--- a/mm/kasan/hw_tags.c
+++ b/mm/kasan/hw_tags.c
@@ -40,7 +40,7 @@ enum kasan_arg_stacktrace {
 
 static enum kasan_arg kasan_arg __ro_after_init;
 static enum kasan_arg_mode kasan_arg_mode __ro_after_init;
-static enum kasan_arg_stacktrace kasan_arg_stacktrace __ro_after_init;
+static enum kasan_arg_stacktrace kasan_arg_stacktrace __initdata;
 
 /* Whether KASAN is enabled at all. */
 DEFINE_STATIC_KEY_FALSE(kasan_flag_enabled);
@@ -116,7 +116,10 @@ static inline const char *kasan_mode_info(void)
 		return "sync";
 }
 
-/* kasan_init_hw_tags_cpu() is called for each CPU. */
+/*
+ * kasan_init_hw_tags_cpu() is called for each CPU.
+ * Not marked as __init as a CPU can be hot-plugged after boot.
+ */
 void kasan_init_hw_tags_cpu(void)
 {
 	/*
-- 
2.25.1