From: Andrey Ryabinin <ryabinin.a.a@gmail.com>
To: Maciej Wieczor-Retman <m.wieczorretman@pm.me>,
Alexander Potapenko <glider@google.com>,
Andrey Konovalov <andreyknvl@gmail.com>,
Dmitry Vyukov <dvyukov@google.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@kernel.org>, Ingo Molnar <mingo@redhat.com>,
Borislav Petkov <bp@alien8.de>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>
Cc: Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com>,
kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v8 08/14] x86/kasan: KASAN raw shadow memory PTE init
Date: Fri, 16 Jan 2026 14:36:24 +0100 [thread overview]
Message-ID: <2077c91e-0789-4ecc-9560-550d9b1a56d5@gmail.com> (raw)
In-Reply-To: <9968297ee3c83a73e1fb05c6415b024d1d2d6a04.1768233085.git.m.wieczorretman@pm.me>
On 1/12/26 6:28 PM, Maciej Wieczor-Retman wrote:
> From: Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com>
>
> In KASAN's generic mode the default value in shadow memory is zero.
> During initialization of shadow memory pages they are allocated and
> zeroed.
>
> In KASAN's tag-based mode the default tag for the arm64 architecture is
> 0xFE which corresponds to any memory that should not be accessed. On x86
> (where tags are 4-bit wide instead of 8-bit wide) that tag is 0xE so
> during the initializations all the bytes in shadow memory pages should
> be filled with it.
>
> Use memblock_alloc_try_nid_raw() instead of memblock_alloc_try_nid() to
> avoid zeroing out the memory so it can be set with the KASAN invalid
> tag.
>
> Signed-off-by: Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com>
> Reviewed-by: Alexander Potapenko <glider@google.com>
> ---
Reviewed-by: Andrey Ryabinin <ryabinin.a.a@gmail.com>
next prev parent reply other threads:[~2026-01-16 13:37 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-12 17:26 [PATCH v8 00/14] kasan: x86: arm64: KASAN tag-based mode for x86 Maciej Wieczor-Retman
2026-01-12 17:27 ` [PATCH v8 01/14] kasan: sw_tags: Use arithmetic shift for shadow computation Maciej Wieczor-Retman
2026-01-15 22:42 ` Andrey Ryabinin
2026-01-16 13:11 ` Maciej Wieczor-Retman
2026-01-12 17:27 ` [PATCH v8 02/14] kasan: arm64: x86: Make special tags arch specific Maciej Wieczor-Retman
2026-01-13 1:21 ` Andrey Konovalov
2026-01-13 17:32 ` Maciej Wieczor-Retman
2026-01-16 13:32 ` Andrey Ryabinin
2026-01-12 17:27 ` [PATCH v8 03/14] kasan: Fix inline mode for x86 tag-based mode Maciej Wieczor-Retman
2026-01-16 13:33 ` Andrey Ryabinin
2026-01-12 17:27 ` [PATCH v8 04/14] x86/kasan: Add arch specific kasan functions Maciej Wieczor-Retman
2026-01-13 1:21 ` Andrey Konovalov
2026-01-13 16:12 ` Maciej Wieczor-Retman
2026-01-16 13:35 ` Andrey Ryabinin
2026-01-12 17:27 ` [PATCH v8 05/14] x86/mm: Reset tag for virtual to physical address conversions Maciej Wieczor-Retman
2026-01-12 17:27 ` [PATCH v8 06/14] mm/execmem: Untag addresses in EXECMEM_ROX related pointer arithmetic Maciej Wieczor-Retman
2026-01-12 17:27 ` [PATCH v8 07/14] x86/mm: Physical address comparisons in fill_p*d/pte Maciej Wieczor-Retman
2026-01-12 17:28 ` [PATCH v8 08/14] x86/kasan: KASAN raw shadow memory PTE init Maciej Wieczor-Retman
2026-01-16 13:36 ` Andrey Ryabinin [this message]
2026-01-12 17:28 ` [PATCH v8 09/14] x86/mm: LAM compatible non-canonical definition Maciej Wieczor-Retman
2026-01-16 14:25 ` Andrey Ryabinin
2026-01-16 14:57 ` Sean Christopherson
2026-01-16 15:56 ` Maciej Wieczor-Retman
2026-01-16 17:00 ` Sean Christopherson
2026-01-16 17:09 ` Maciej Wieczor-Retman
2026-01-12 17:28 ` [PATCH v8 10/14] x86/mm: LAM initialization Maciej Wieczor-Retman
2026-01-12 17:28 ` [PATCH v8 11/14] x86: Minimal SLAB alignment Maciej Wieczor-Retman
2026-01-12 17:28 ` [PATCH v8 12/14] arm64: Unify software tag-based KASAN inline recovery path Maciej Wieczor-Retman
2026-01-12 17:28 ` [PATCH v8 13/14] x86/kasan: Logical bit shift for kasan_mem_to_shadow Maciej Wieczor-Retman
2026-01-13 1:21 ` Andrey Konovalov
2026-01-14 16:52 ` Maciej Wieczor-Retman
2026-01-15 3:57 ` Andrey Konovalov
2026-01-15 16:43 ` Maciej Wieczor-Retman
2026-01-17 1:21 ` Andrey Konovalov
2026-01-17 6:53 ` Maciej Wieczór-Retman
2026-01-19 11:40 ` Maciej Wieczor-Retman
2026-01-12 17:28 ` [PATCH v8 14/14] x86/kasan: Make software tag-based kasan available Maciej Wieczor-Retman
2026-01-13 1:21 ` Andrey Konovalov
2026-01-13 15:31 ` Maciej Wieczor-Retman
2026-01-13 11:45 ` Borislav Petkov
2026-01-13 16:00 ` Maciej Wieczor-Retman
2026-01-13 16:10 ` Borislav Petkov
2026-01-12 18:29 ` [PATCH v8 00/14] kasan: x86: arm64: KASAN tag-based mode for x86 Andrew Morton
2026-01-12 20:08 ` Maciej Wieczór-Retman
2026-01-12 20:53 ` Andrew Morton
2026-01-13 1:47 ` Andrey Konovalov
2026-01-12 20:27 ` Dave Hansen
2026-01-13 11:47 ` Borislav Petkov
2026-01-13 17:34 ` Andrew Morton
2026-01-22 17:25 ` Maciej Wieczor-Retman
2026-01-13 1:44 ` Andrey Konovalov
2026-01-19 16:33 ` Andrey Ryabinin
2026-01-19 19:43 ` Maciej Wieczor-Retman
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