linux-kernel - [PATCH mm v3 12/38] kasan, page_alloc: move SetPageSkipKASanPoison in post_alloc

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Message-Id: <a8a713cfe1c7a8836d444c9f12ee7bf5f9ea279c.1639432170.git.andreyknvl@google.com>
Date:   Mon, 13 Dec 2021 22:53:02 +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 12/38] kasan, page_alloc: move SetPageSkipKASanPoison in post_alloc_hook

From: Andrey Konovalov <andreyknvl@...gle.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
CONFIG_KASAN_HW_TAGS 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@...gle.com>
---
 mm/page_alloc.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 2d1e63a01ed8..3dba92accfb7 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 +2442,10 @@ 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 (IS_ENABLED(CONFIG_KASAN_HW_TAGS) &&
+	    (gfp_flags & __GFP_SKIP_KASAN_POISON))
+		SetPageSkipKASanPoison(page);
 
 	set_page_owner(page, order, gfp_flags);
 	page_table_check_alloc(page, order);
-- 
2.25.1