From: Dev Jain <dev.jain@arm.com>
To: arnd@arndb.de, kees@kernel.org, mingo@redhat.com,
peterz@infradead.org, juri.lelli@redhat.com,
vincent.guittot@linaro.org, akpm@linux-foundation.org,
david@kernel.org, urezki@gmail.com
Cc: dietmar.eggemann@arm.com, rostedt@goodmis.org,
bsegall@google.com, mgorman@suse.de, vschneid@redhat.com,
ljs@kernel.org, Liam.Howlett@oracle.com, vbabka@kernel.org,
rppt@kernel.org, surenb@google.com, mhocko@suse.com,
tglx@kernel.org, usama.anjum@arm.com,
mathieu.desnoyers@efficios.com, linux-arch@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Ryan Roberts <ryan.roberts@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>
Subject: [PATCH v3 3/3] mm: skip KASAN tagging for page-allocated page tables
Date: Fri, 24 Apr 2026 18:31:57 +0530 [thread overview]
Message-ID: <20260424130157.3163009-4-dev.jain@arm.com> (raw)
In-Reply-To: <20260424130157.3163009-1-dev.jain@arm.com>
From: Muhammad Usama Anjum <usama.anjum@arm.com>
Page tables are always accessed via the linear mapping with a match-all
tag, so HW-tag KASAN never checks them. For page-allocated tables (PTEs
and PGDs etc), avoid the tag setup and poisoning overhead by using
__GFP_SKIP_KASAN. SLUB-backed page tables are unchanged for now. (They
aren't widely used and require more SLUB related skip logic. Leave it
later.)
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Muhammad Usama Anjum <usama.anjum@arm.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
---
include/asm-generic/pgalloc.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/asm-generic/pgalloc.h b/include/asm-generic/pgalloc.h
index 57137d3ac1592..051aa1331051c 100644
--- a/include/asm-generic/pgalloc.h
+++ b/include/asm-generic/pgalloc.h
@@ -4,7 +4,7 @@
#ifdef CONFIG_MMU
-#define GFP_PGTABLE_KERNEL (GFP_KERNEL | __GFP_ZERO)
+#define GFP_PGTABLE_KERNEL (GFP_KERNEL | __GFP_ZERO | __GFP_SKIP_KASAN)
#define GFP_PGTABLE_USER (GFP_PGTABLE_KERNEL | __GFP_ACCOUNT)
/**
--
2.34.1
next prev parent reply other threads:[~2026-04-24 13:02 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-24 13:01 [PATCH v3 0/3] kasan: hw_tags: Disable tagging for stack and page-tables Dev Jain
2026-04-24 13:01 ` [PATCH v3 1/3] vmalloc: add __GFP_SKIP_KASAN support Dev Jain
2026-04-24 18:32 ` Catalin Marinas
2026-04-25 9:14 ` Catalin Marinas
2026-04-24 13:01 ` [PATCH v3 2/3] kasan: skip HW tagging for all kernel thread stacks Dev Jain
2026-04-24 13:01 ` Dev Jain [this message]
2026-04-24 17:41 ` [PATCH v3 3/3] mm: skip KASAN tagging for page-allocated page tables Catalin Marinas
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