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Message-Id: <0ecebd0d7ccd79150e3620ea4185a32d3dfe912f.1643047180.git.andreyknvl@google.com>
Date: Mon, 24 Jan 2022 19:02:22 +0100
From: andrey.konovalov@...ux.dev
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: Andrey Konovalov <andreyknvl@...il.com>,
Marco Elver <elver@...gle.com>,
Alexander Potapenko <glider@...gle.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 v6 14/39] kasan, page_alloc: rework kasan_unpoison_pages call site
From: Andrey Konovalov <andreyknvl@...gle.com>
Rework the checks around kasan_unpoison_pages() call in
post_alloc_hook().
The logical condition for calling this function is:
- If a software KASAN mode is enabled, we need to mark shadow memory.
- Otherwise, HW_TAGS KASAN is enabled, and it only makes sense to
set tags if they haven't already been cleared by tag_clear_highpage(),
which is indicated by init_tags.
This patch concludes the changes for post_alloc_hook().
Signed-off-by: Andrey Konovalov <andreyknvl@...gle.com>
---
Changes v3->v4:
- Make the confition checks more explicit.
- Update patch description.
---
mm/page_alloc.c | 19 ++++++++++++-------
1 file changed, 12 insertions(+), 7 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 2784bd478942..3af38e323391 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2434,15 +2434,20 @@ inline void post_alloc_hook(struct page *page, unsigned int order,
/* Note that memory is already initialized by the loop above. */
init = false;
}
- if (kasan_has_integrated_init()) {
- if (!init_tags) {
- kasan_unpoison_pages(page, order, init);
+ /*
+ * If either a software KASAN mode is enabled, or,
+ * in the case of hardware tag-based KASAN,
+ * if memory tags have not been cleared via tag_clear_highpage().
+ */
+ if (IS_ENABLED(CONFIG_KASAN_GENERIC) ||
+ IS_ENABLED(CONFIG_KASAN_SW_TAGS) ||
+ kasan_hw_tags_enabled() && !init_tags) {
+ /* Mark shadow memory or set memory tags. */
+ kasan_unpoison_pages(page, order, init);
- /* Note that memory is already initialized by KASAN. */
+ /* Note that memory is already initialized by KASAN. */
+ if (kasan_has_integrated_init())
init = false;
- }
- } else {
- kasan_unpoison_pages(page, order, init);
}
/* If memory is still not initialized, do it now. */
if (init)
--
2.25.1
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