From: Andrew Morton <akpm@linux-foundation.org>
To: andrey.konovalov@linux.dev
Cc: Andrey Konovalov <andreyknvl@gmail.com>,
Marco Elver <elver@google.com>,
Alexander Potapenko <glider@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
Andrey Ryabinin <ryabinin.a.a@gmail.com>,
kasan-dev@googlegroups.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org,
Andrey Konovalov <andreyknvl@google.com>,
Peter Collingbourne <pcc@google.com>
Subject: Re: [PATCH mm] kasan: reset page tags properly with sampling
Date: Tue, 24 Jan 2023 12:45:04 -0800 [thread overview]
Message-ID: <20230124124504.2b21f0fde58af208a4f4e290@linux-foundation.org> (raw)
In-Reply-To: <24ea20c1b19c2b4b56cf9f5b354915f8dbccfc77.1674592496.git.andreyknvl@google.com>
On Tue, 24 Jan 2023 21:35:26 +0100 andrey.konovalov@linux.dev wrote:
> The implementation of page_alloc poisoning sampling assumed that
> tag_clear_highpage resets page tags for __GFP_ZEROTAGS allocations.
> However, this is no longer the case since commit 70c248aca9e7
> ("mm: kasan: Skip unpoisoning of user pages").
>
> This leads to kernel crashes when MTE-enabled userspace mappings are
> used with Hardware Tag-Based KASAN enabled.
>
> Reset page tags for __GFP_ZEROTAGS allocations in post_alloc_hook().
>
> Also clarify and fix related comments.
I assume this is a fix against 44383cef54c0 ("kasan: allow sampling
page_alloc allocations for HW_TAGS") which is presently in mm-stable,
yes?
next prev parent reply other threads:[~2023-01-24 20:45 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-24 20:35 andrey.konovalov
2023-01-24 20:45 ` Andrew Morton [this message]
2023-01-24 20:46 ` Andrey Konovalov
2023-01-24 21:11 ` Andrew Morton
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