From: Catalin Marinas <catalin.marinas@arm.com>
To: Muhammad Usama Anjum <usama.anjum@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>, Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Juri Lelli <juri.lelli@redhat.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Steven Rostedt <rostedt@goodmis.org>,
Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
Valentin Schneider <vschneid@redhat.com>,
Kees Cook <kees@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
David Hildenbrand <david@kernel.org>,
Lorenzo Stoakes <ljs@kernel.org>,
"Liam R. Howlett" <Liam.Howlett@oracle.com>,
Vlastimil Babka <vbabka@kernel.org>,
Mike Rapoport <rppt@kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
Michal Hocko <mhocko@suse.com>,
Uladzislau Rezki <urezki@gmail.com>,
linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, Andrey Konovalov <andreyknvl@gmail.com>,
Marco Elver <elver@google.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Peter Collingbourne <pcc@google.com>,
Will Deacon <will@kernel.org>,
Ryan.Roberts@arm.com, david.hildenbrand@arm.com
Subject: Re: [PATCH v2 2/3] kasan: skip HW tagging for all kernel thread stacks
Date: Fri, 10 Apr 2026 19:36:58 +0100 [thread overview]
Message-ID: <adlDSiuBeSduK0mj@arm.com> (raw)
In-Reply-To: <adlCN9sUcQdWbf_i@arm.com>
On Fri, Apr 10, 2026 at 07:32:23PM +0100, Catalin Marinas wrote:
> What the original approach might help with is use-after-realloc in case
> we had a tagged pointer in a past life of a page and it still works now.
> Oh well, that's I guess for other types of hardening to address like
> delayed reallocation.
Another thought (for a separate series) - we could try to map the stack
as Untagged (unless stack tagging is enabled; needs compiler
instrumentation) and enable canonical tag checking (newer addition to
MTE). This way, any stray tagged pointer won't work on the stack since
it needs a 0xf tag (canonical).
--
Catalin
next prev parent reply other threads:[~2026-04-10 18:37 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-24 13:26 [PATCH v2 0/3] KASAN: HW_TAGS: Disable tagging for stack and page-tables Muhammad Usama Anjum
2026-03-24 13:26 ` [PATCH v2 1/3] vmalloc: add __GFP_SKIP_KASAN support Muhammad Usama Anjum
2026-04-10 18:10 ` Catalin Marinas
2026-03-24 13:26 ` [PATCH v2 2/3] kasan: skip HW tagging for all kernel thread stacks Muhammad Usama Anjum
2026-04-10 18:32 ` Catalin Marinas
2026-04-10 18:36 ` Catalin Marinas [this message]
2026-03-24 13:26 ` [PATCH v2 3/3] mm: skip KASAN tagging for page-allocated page tables Muhammad Usama Anjum
2026-04-10 18:19 ` Catalin Marinas
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