linux-kernel - [PATCH mm v3 32/38] kasan: mark kasan_arg_stacktrace as _

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Message-Id: <7825a5fecec3626441ed3fe734090e9e3ab9a0f9.1639432170.git.andreyknvl@google.com>
Date:   Mon, 13 Dec 2021 22:54:28 +0100
From:   andrey.konovalov@...ux.dev
To:     Marco Elver <elver@...gle.com>,
        Alexander Potapenko <glider@...gle.com>,
        Andrew Morton <akpm@...ux-foundation.org>
Cc:     Andrey Konovalov <andreyknvl@...il.com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Andrey Ryabinin <ryabinin.a.a@...il.com>,
        kasan-dev@...glegroups.com, linux-mm@...ck.org,
        Vincenzo Frascino <vincenzo.frascino@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        linux-arm-kernel@...ts.infradead.org,
        Peter Collingbourne <pcc@...gle.com>,
        Evgenii Stepanov <eugenis@...gle.com>,
        linux-kernel@...r.kernel.org,
        Andrey Konovalov <andreyknvl@...gle.com>
Subject: [PATCH mm v3 32/38] kasan: mark kasan_arg_stacktrace as __initdata

From: Andrey Konovalov <andreyknvl@...gle.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@...gle.com>
Suggested-by: Marco Elver <elver@...gle.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 bbcf6f914490..fb08fe1a3cf7 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