From: Dan Williams <dan.j.williams@intel.com>
To: Wei Yang <richardw.yang@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Oscar Salvador <osalvador@suse.de>, Linux MM <linux-mm@kvack.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Baoquan He <bhe@redhat.com>, David Hildenbrand <david@redhat.com>
Subject: Re: [PATCH 3/3] mm/sparsemem: avoid memmap overwrite for non-SPARSEMEM_VMEMMAP
Date: Thu, 6 Feb 2020 18:06:54 -0800 [thread overview]
Message-ID: <CAPcyv4hLW5Ww1Bo0MmNi8fzUNQEvudtWpGOK23MWaiqQ+MemfA@mail.gmail.com> (raw)
In-Reply-To: <20200206231629.14151-4-richardw.yang@linux.intel.com>
On Thu, Feb 6, 2020 at 3:17 PM Wei Yang <richardw.yang@linux.intel.com> wrote:
>
> In case of SPARSEMEM, populate_section_memmap() would allocate memmap
> for the whole section, even we just want a sub-section. This would lead
> to memmap overwrite if we a sub-section to an already populated section.
>
> Just return the populated memmap for non-SPARSEMEM_VMEMMAP case.
>
> Fixes: ba72b4c8cf60 ("mm/sparsemem: support sub-section hotplug")
> Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
> CC: Dan Williams <dan.j.williams@intel.com>
> ---
> mm/sparse.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/mm/sparse.c b/mm/sparse.c
> index 56816f653588..c75ca40db513 100644
> --- a/mm/sparse.c
> +++ b/mm/sparse.c
> @@ -836,6 +836,16 @@ static struct page * __meminit section_activate(int nid, unsigned long pfn,
> if (nr_pages < PAGES_PER_SECTION && early_section(ms))
> return pfn_to_page(pfn);
>
> + /*
> + * If it is not SPARSEMEM_VMEMMAP, we always populate memmap for the
> + * whole section, even for a sub-section.
> + *
> + * Return its memmap if already populated to avoid memmap overwrite.
> + */
> + if (!IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP) &&
> + valid_section(ms))
> + return __section_mem_map_addr(ms);
Again, is check_pfn_span() failing to prevent this path?
next prev parent reply other threads:[~2020-02-07 2:07 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-06 23:16 [PATCH 0/3] Fixes "mm/sparsemem: support sub-section hotplug" Wei Yang
2020-02-06 23:16 ` [PATCH 1/3] mm/sparsemem: adjust memmap only for SPARSEMEM_VMEMMAP Wei Yang
2020-02-07 2:00 ` Dan Williams
2020-02-07 11:06 ` Wei Yang
2020-02-06 23:16 ` [PATCH 2/3] mm/sparsemem: get physical address to page struct instead of virtual address to pfn Wei Yang
2020-02-07 2:19 ` Dan Williams
2020-02-07 3:10 ` Baoquan He
2020-02-07 3:21 ` Dan Williams
2020-02-07 3:36 ` Baoquan He
2020-02-07 4:05 ` Dan Williams
2020-02-07 11:13 ` Wei Yang
2020-02-07 12:14 ` Wei Yang
2020-02-07 16:44 ` Dan Williams
2020-02-07 10:51 ` Wei Yang
2020-02-07 11:26 ` Wei Yang
2020-02-09 13:50 ` Baoquan He
2020-02-09 14:14 ` David Hildenbrand
2020-02-10 0:36 ` Wei Yang
2020-02-07 4:11 ` Baoquan He
2020-02-07 10:53 ` Wei Yang
2020-02-06 23:16 ` [PATCH 3/3] mm/sparsemem: avoid memmap overwrite for non-SPARSEMEM_VMEMMAP Wei Yang
2020-02-07 2:06 ` Dan Williams [this message]
2020-02-07 3:50 ` Baoquan He
2020-02-07 11:02 ` Wei Yang
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