From: "Jose A. Perez de Azpillaga" <azpijr@gmail.com>
To: Muchun Song <songmuchun@bytedance.com>,
Andrew Morton <akpm@linux-foundation.org>,
David Hildenbrand <david@kernel.org>,
Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Lorenzo Stoakes <ljs@kernel.org>,
"Liam R . Howlett" <liam@infradead.org>,
Vlastimil Babka <vbabka@kernel.org>,
Mike Rapoport <rppt@kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
Michal Hocko <mhocko@suse.com>,
Alexander Potapenko <glider@google.com>,
Andrey Konovalov <andreyknvl@gmail.com>,
Dmitry Vyukov <dvyukov@google.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Dan Williams <djbw@kernel.org>,
linux-mm@kvack.org, kasan-dev@googlegroups.com,
linux-kernel@vger.kernel.org, stable@vger.kernel.org,
muchun.song@linux.dev
Subject: Re: [PATCH v2] kasan: fix runtime shadow page table synchronization
Date: Sun, 18 Oct 2026 10:48:25 +0200 [thread overview]
Message-ID: <6b17c6a5-5164-402f-8d97-2b25f4f9ae8d@gmail.com> (raw)
In-Reply-To: <20261018043501.3257632-1-songmuchun@bytedance.com>
On 10/18/26 6:35 AM, Muchun Song wrote:
> - if (IS_ALIGNED(addr, PMD_SIZE) && end - addr >= PMD_SIZE) {
> + if (IS_ALIGNED(addr, PMD_SIZE) && end - addr >= PMD_SIZE &&
> + pmd_none(*pmd)) {
> pmd_populate_kernel(&init_mm, pmd,
> lm_alias(kasan_early_shadow_pte));
what if the entry already points at the early shadow table? this walks
down into it then, which loongarch does on every boot.
[snip]
> - zero_pmd_populate(pud, addr, next);
> + ret = zero_pmd_populate(pud, addr, next, mask);
> + if (ret)
> + return ret;
isn't this a separate fix? it's not in the changelog.
[snip]
> if (kasan_pud_table(*p4d)) {
> + if (ARCH_PAGE_TABLE_SYNC_MASK & PGTBL_P4D_MODIFIED)
> + continue;
> +
doesn't this leave the range on the zero shadow, which memory onlined
there later then keeps? would always allocating a table at the synced
level once slab is up avoid that?
--
cheers,
jose a. p-a
prev parent reply other threads:[~2026-10-18 8:48 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-18 4:35 Muchun Song
2026-10-18 8:48 ` Jose A. Perez de Azpillaga [this message]
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