lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20200207110629.qkovh23k7ihzh4a3@master>
Date:   Fri, 7 Feb 2020 11:06:29 +0000
From:   Wei Yang <richard.weiyang@...il.com>
To:     Dan Williams <dan.j.williams@...el.com>
Cc:     Wei Yang <richardw.yang@...ux.intel.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Oscar Salvador <osalvador@...e.de>,
        Linux MM <linux-mm@...ck.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Baoquan He <bhe@...hat.com>,
        David Hildenbrand <david@...hat.com>
Subject: Re: [PATCH 1/3] mm/sparsemem: adjust memmap only for
 SPARSEMEM_VMEMMAP

On Thu, Feb 06, 2020 at 06:00:13PM -0800, Dan Williams wrote:
>On Thu, Feb 6, 2020 at 3:17 PM Wei Yang <richardw.yang@...ux.intel.com> wrote:
>>
>> Only when SPARSEMEM_VMEMMAP is set, memmap returned from
>> section_activate() points to sub-section page struct. Otherwise, memmap
>> already points to the whole section page struct.
>>
>> This means only for SPARSEMEM_VMEMMAP, we need to adjust memmap for
>> sub-section case.
>>
>> Fixes: ba72b4c8cf60 ("mm/sparsemem: support sub-section hotplug")
>> Signed-off-by: Wei Yang <richardw.yang@...ux.intel.com>
>> CC: Dan Williams <dan.j.williams@...el.com>
>> ---
>>  mm/sparse.c | 3 ++-
>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/mm/sparse.c b/mm/sparse.c
>> index 586d85662978..b5da121bdd6e 100644
>> --- a/mm/sparse.c
>> +++ b/mm/sparse.c
>> @@ -886,7 +886,8 @@ int __meminit sparse_add_section(int nid, unsigned long start_pfn,
>>         section_mark_present(ms);
>>
>>         /* Align memmap to section boundary in the subsection case */
>> -       if (section_nr_to_pfn(section_nr) != start_pfn)
>> +       if (IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP) &&
>> +               section_nr_to_pfn(section_nr) != start_pfn)
>
>Aren't we assured that start_pfn is always section aligned in the
>SPARSEMEM case? That's the role of check_pfn_span(). Does the change
>have a runtime impact or is this just theoretical?

You are right, I missed this point.

Thanks

-- 
Wei Yang
Help you, Help me

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ