From:   andrey.konovalov@linux.dev
To:     Marco Elver <elver@google.com>,
        Alexander Potapenko <glider@google.com>,
        Andrew Morton <akpm@linux-foundation.org>
Cc:     Andrey Konovalov <andreyknvl@gmail.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 v4 12/39] kasan, page_alloc: move SetPageSkipKASanPoison in post_alloc_hook
Date:   Mon, 20 Dec 2021 22:59:27 +0100
Message-Id: <c85e5280566f113353f0c0f542304208e186dcaa.1640036051.git.andreyknvl@google.com>
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From: Andrey Konovalov <andreyknvl@google.com>

Pull the SetPageSkipKASanPoison() call in post_alloc_hook() out of the
big if clause for better code readability. This also allows for more
simplifications in the following patches.

Also turn the kasan_has_integrated_init() check into the proper
kasan_hw_tags_enabled() one. These checks evaluate to the same value,
but logically skipping kasan poisoning has nothing to do with
integrated init.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>

---

Changes v3->v4:
- Use proper kasan_hw_tags_enabled() check instead of
  IS_ENABLED(CONFIG_KASAN_HW_TAGS).
---
 mm/page_alloc.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 2d1e63a01ed8..076c43f369b4 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2434,9 +2434,6 @@ inline void post_alloc_hook(struct page *page, unsigned int order,
 		init = false;
 	}
 	if (kasan_has_integrated_init()) {
-		if (gfp_flags & __GFP_SKIP_KASAN_POISON)
-			SetPageSkipKASanPoison(page);
-
 		if (!init_tags)
 			kasan_unpoison_pages(page, order, init);
 	} else {
@@ -2445,6 +2442,9 @@ inline void post_alloc_hook(struct page *page, unsigned int order,
 		if (init)
 			kernel_init_free_pages(page, 1 << order);
 	}
+	/* Propagate __GFP_SKIP_KASAN_POISON to page flags. */
+	if (kasan_hw_tags_enabled() && (gfp_flags & __GFP_SKIP_KASAN_POISON))
+		SetPageSkipKASanPoison(page);
 
 	set_page_owner(page, order, gfp_flags);
 	page_table_check_alloc(page, order);
-- 
2.25.1