linux-kernel - Re: [PATCH v2 RESEND] mm/sparsemem: pfn_to

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: <CAPcyv4isoKSo2TtP3_VzdPQwdfc2O=KAv44LkqSSTccP7Cnh7A@mail.gmail.com>
Date:   Wed, 19 Feb 2020 08:37:25 -0800
From:   Dan Williams <dan.j.williams@...el.com>
To:     Mike Rapoport <rppt@...ux.ibm.com>
Cc:     Baoquan He <bhe@...hat.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux MM <linux-mm@...ck.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Wei Yang <richardw.yang@...ux.intel.com>,
        David Hildenbrand <david@...hat.com>,
        Oscar Salvador <osalvador@...e.de>,
        Michal Hocko <mhocko@...e.com>
Subject: Re: [PATCH v2 RESEND] mm/sparsemem: pfn_to_page is not valid yet on SPARSEMEM

On Wed, Feb 19, 2020 at 12:57 AM Mike Rapoport <rppt@...ux.ibm.com> wrote:
>
> On Tue, Feb 18, 2020 at 07:25:15PM -0800, Dan Williams wrote:
> > On Tue, Feb 18, 2020 at 7:05 PM Baoquan He <bhe@...hat.com> wrote:
> > >
> > > From: Wei Yang <richardw.yang@...ux.intel.com>
> > >
> > > When we use SPARSEMEM instead of SPARSEMEM_VMEMMAP, pfn_to_page()
> > > doesn't work before sparse_init_one_section() is called. This leads to a
> > > crash when hotplug memory:
> >
> > I'd also add:
> >
> > "On x86 the impact is limited to x86_32 builds, or x86_64
> > configurations that override the default setting for
> > SPARSEMEM_VMEMMAP".
>
> Do we also want to check how it affects, say, arm64, ia64 and ppc? ;-)

Sure, I just did not take the time to look up their respective default
stances on SPARSEMEM_VMEMMAP. For a distro looking to backport this
commit I think it's helpful for them to understand if they are exposed
or not.