From: Andrey Ryabinin <ryabinin.a.a@gmail.com>
To: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>,
kasan-dev@googlegroups.com
Cc: linux-mm@kvack.org, Alexander Potapenko <glider@google.com>,
Andrey Konovalov <andreyknvl@gmail.com>,
Dmitry Vyukov <dvyukov@google.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
linuxppc-dev@lists.ozlabs.org, stable@vger.kernel.org,
Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Subject: Re: [PATCH v2] mm/kasan: Fix double free for kasan pXds
Date: Thu, 5 Mar 2026 12:31:03 -0600 [thread overview]
Message-ID: <CAPAsAGxB6RGSYzMq=tjQQmEDu3QP+v_AqmkbWTRyqkk+K35o-w@mail.gmail.com> (raw)
In-Reply-To: <2f9135c7866c6e0d06e960993b8a5674a9ebc7ec.1771938394.git.ritesh.list@gmail.com>
"Ritesh Harjani (IBM)" <ritesh.list@gmail.com> writes:
> kasan_free_pxd() assumes the page table is always struct page aligned.
> But that's not always the case for all architectures. E.g. In case of
> powerpc with 64K pagesize, PUD table (of size 4096) comes from slab
> cache named pgtable-2^9. Hence instead of page_to_virt(pxd_page()) let's
> just directly pass the start of the pxd table which is passed as the 1st
> argument.
>
> This fixes the below double free kasan issue seen with PMEM:
>
> radix-mmu: Mapped 0x0000047d10000000-0x0000047f90000000 with 2.00 MiB pages
> ==================================================================
> BUG: KASAN: double-free in kasan_remove_zero_shadow+0x9c4/0xa20
...
>
> Fixes: 0207df4fa1a8 ("kernel/memremap, kasan: make ZONE_DEVICE with work with KASAN")
> Cc: stable@vger.kernel.org
> Reported-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
> Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
>
Reviewed-by: Andrey Ryabinin <ryabinin.a.a@gmail.com>
prev parent reply other threads:[~2026-03-05 18:31 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-24 13:23 Ritesh Harjani (IBM)
2026-03-02 10:29 ` Alexander Potapenko
2026-03-05 18:31 ` Andrey Ryabinin [this message]
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