From: Will Deacon <will@kernel.org>
To: Maciej Wieczor-Retman <m.wieczorretman@pm.me>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>,
Alexander Potapenko <glider@google.com>,
Andrey Konovalov <andreyknvl@gmail.com>,
Dmitry Vyukov <dvyukov@google.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Andrew Morton <akpm@linux-foundation.org>,
David Hildenbrand <david@redhat.com>,
Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
"Liam R. Howlett" <Liam.Howlett@oracle.com>,
Vlastimil Babka <vbabka@suse.cz>, Mike Rapoport <rppt@kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
Michal Hocko <mhocko@suse.com>,
Samuel Holland <samuel.holland@sifive.com>,
Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com>,
linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com,
linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org
Subject: Re: [PATCH v7 02/15] kasan: arm64: x86: Make special tags arch specific
Date: Fri, 9 Jan 2026 13:43:25 +0000 [thread overview]
Message-ID: <aWEF_eJ9Bnn5-8dZ@willie-the-truck> (raw)
In-Reply-To: <aWEDDjQms8zbMgsB@wieczorr-mobl1.localdomain>
On Fri, Jan 09, 2026 at 01:37:49PM +0000, Maciej Wieczor-Retman wrote:
> Hi, and thanks for looking at the patches!
>
> On 2026-01-08 at 17:56:39 +0000, Will Deacon wrote:
> >On Wed, Dec 10, 2025 at 05:28:43PM +0000, Maciej Wieczor-Retman wrote:
> >> From: Samuel Holland <samuel.holland@sifive.com>
> ...
> >> +#ifdef CONFIG_KASAN_HW_TAGS
> >> +#define KASAN_TAG_MIN 0xF0 /* minimum value for random tags */
> >> +#define KASAN_TAG_WIDTH 4
> >> +#else
> >> +#define KASAN_TAG_WIDTH 8
> >> +#endif
> >
> >Shouldn't this be 0 when KASAN is not in use at all?
> >
> >Will
>
> This file (as well as the x86 version) gets included in
> include/linux/kasan-tags.h:
>
> #if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS)
> #include <asm/kasan-tags.h>
> #endif
>
> #ifndef KASAN_TAG_WIDTH
> #define KASAN_TAG_WIDTH 0
> #endif
>
> So the 8 or 4 value is only assigned if SW_TAGS or HW_TAGS are enabled.
> Otherwise it's set to zero.
Thanks for the explanation, I'd missed the conditional inclusion of the
arch header.
In which case, the arm64 side looks fine to me:
Acked-by: Will Deacon <will@kernel.org>
Cheers,
Will
next prev parent reply other threads:[~2026-01-09 13:43 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-10 17:14 [PATCH v7 00/15] kasan: x86: arm64: KASAN tag-based mode for x86 Maciej Wieczor-Retman
2025-12-10 17:28 ` [PATCH v7 01/15] kasan: sw_tags: Use arithmetic shift for shadow computation Maciej Wieczor-Retman
2025-12-10 17:28 ` [PATCH v7 02/15] kasan: arm64: x86: Make special tags arch specific Maciej Wieczor-Retman
2026-01-08 17:56 ` Will Deacon
2026-01-09 13:37 ` Maciej Wieczor-Retman
2026-01-09 13:43 ` Will Deacon [this message]
2025-12-10 17:29 ` [PATCH v7 04/15] x86/kasan: Add arch specific kasan functions Maciej Wieczor-Retman
2025-12-10 17:29 ` [PATCH v7 06/15] mm/execmem: Untag addresses in EXECMEM_ROX related pointer arithmetic Maciej Wieczor-Retman
2025-12-10 17:30 ` [PATCH v7 14/15] x86/kasan: Logical bit shift for kasan_mem_to_shadow Maciej Wieczor-Retman
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