From: David Hildenbrand <david@redhat.com>
To: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
syzbot+7d917f67c05066cec295@syzkaller.appspotmail.com,
Andrew Morton <akpm@linux-foundation.org>,
Jann Horn <jannh@google.com>
Subject: Re: [PATCH v1] mm/pagewalk: fix usage of pmd_leaf()/pud_leaf() without present check
Date: Tue, 15 Oct 2024 16:40:47 +0200 [thread overview]
Message-ID: <ef49981b-b4ae-4a39-bfb2-7c2065d7bc98@redhat.com> (raw)
In-Reply-To: <bu3aq2gxcfkjxocu3uzowvevlv6rgeihepc36cwuhh44xqydkc@3ghgml6xnlgx>
On 15.10.24 16:32, Kirill A. Shutemov wrote:
> On Tue, Oct 15, 2024 at 01:12:36PM +0200, David Hildenbrand wrote:
>> pmd_leaf()/pud_leaf() only implies a pmd_present()/pud_present() check on
>> some architectures.
>
> Should we clarify what behaviour we actually want from arch code?
We probably should document somewhere that things like pmd_special(),
pmd_leaf() ... should only be used when we know that the PMD is present.
I wonder if we should even add ways to detect mis-use
Jann also raised that recently in a private message, that it is rather
unclear (well, and repeatedly leads to issues) when pmd_leaf() is valid
to be called.
Thanks!
--
Cheers,
David / dhildenb
next prev parent reply other threads:[~2024-10-15 14:40 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-15 11:12 David Hildenbrand
2024-10-15 13:13 ` David Hildenbrand
2024-10-16 10:58 ` Qi Zheng
2024-10-16 11:05 ` David Hildenbrand
2024-10-16 22:44 ` Andrew Morton
2024-10-15 14:32 ` Kirill A. Shutemov
2024-10-15 14:40 ` David Hildenbrand [this message]
2024-10-15 14:43 ` Jann Horn
2024-10-15 15:45 ` Zi Yan
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