From: Andrew Morton <akpm@linux-foundation.org>
To: Peter Collingbourne <pcc@google.com>
Cc: catalin.marinas@arm.com, andreyknvl@gmail.com,
linux-mm@kvack.org, kasan-dev@googlegroups.com,
ryabinin.a.a@gmail.com, linux-arm-kernel@lists.infradead.org,
vincenzo.frascino@arm.com, will@kernel.org, eugenis@google.com,
stable@vger.kernel.org
Subject: Re: [PATCH v3 1/2] Revert "kasan: drop skip_kasan_poison variable in free_pages_prepare"
Date: Wed, 8 Mar 2023 17:46:08 -0800 [thread overview]
Message-ID: <20230308174608.e66ed98c97ea29934d99c596@linux-foundation.org> (raw)
In-Reply-To: <20230301003545.282859-2-pcc@google.com>
On Tue, 28 Feb 2023 16:35:44 -0800 Peter Collingbourne <pcc@google.com> wrote:
> This reverts commit 487a32ec24be819e747af8c2ab0d5c515508086a.
>
> The should_skip_kasan_poison() function reads the PG_skip_kasan_poison
> flag from page->flags. However, this line of code in free_pages_prepare():
>
> page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
>
> clears most of page->flags, including PG_skip_kasan_poison, before calling
> should_skip_kasan_poison(), which meant that it would never return true
> as a result of the page flag being set. Therefore, fix the code to call
> should_skip_kasan_poison() before clearing the flags, as we were doing
> before the reverted patch.
What are the user visible effects of this change?
> Cc: <stable@vger.kernel.org> # 6.1
Especially if it's cc:stable.
Thanks.
next prev parent reply other threads:[~2023-03-09 1:46 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-01 0:35 [PATCH v3 0/2] kasan: bugfix and cleanup Peter Collingbourne
2023-03-01 0:35 ` [PATCH v3 1/2] Revert "kasan: drop skip_kasan_poison variable in free_pages_prepare" Peter Collingbourne
2023-03-09 1:46 ` Andrew Morton [this message]
2023-03-09 21:36 ` Peter Collingbourne
2023-03-01 0:35 ` [PATCH v3 2/2] kasan: remove PG_skip_kasan_poison flag Peter Collingbourne
2023-03-01 0:57 ` Andrey Konovalov
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