From: Michal Hocko <mhocko@kernel.org>
To: Alastair D'Silva <alastair@d-silva.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Pavel Tatashin <pasha.tatashin@oracle.com>,
Oscar Salvador <osalvador@suse.de>,
Mike Rapoport <rppt@linux.ibm.com>, Baoquan He <bhe@redhat.com>,
Qian Cai <cai@lca.pw>, Logan Gunthorpe <logang@deltatee.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH v2 2/3] mm: don't hide potentially null memmap pointer in sparse_remove_one_section
Date: Wed, 26 Jun 2019 08:59:35 +0200 [thread overview]
Message-ID: <20190626065935.GL17798@dhcp22.suse.cz> (raw)
In-Reply-To: <edac179f0626a6e0bd91922d876934abf1b9bb19.camel@d-silva.org>
On Wed 26-06-19 16:30:55, Alastair D'Silva wrote:
> On Wed, 2019-06-26 at 08:23 +0200, Michal Hocko wrote:
> > On Wed 26-06-19 16:11:22, Alastair D'Silva wrote:
> > > From: Alastair D'Silva <alastair@d-silva.org>
> > >
> > > By adding offset to memmap before passing it in to
> > > clear_hwpoisoned_pages,
> > > we hide a potentially null memmap from the null check inside
> > > clear_hwpoisoned_pages.
> > >
> > > This patch passes the offset to clear_hwpoisoned_pages instead,
> > > allowing
> > > memmap to successfully peform it's null check.
> >
> > Same issue with the changelog as the previous patch (missing WHY).
> >
>
> The first paragraph explains what the problem is with the existing code
> (same applies to 1/3 too).
Under what conditions that happens? Is this a theoretical problem or can
you hit this by a (buggy) code? Please be much more specific.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2019-06-26 6:59 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-26 6:11 [PATCH v2 0/3] mm: Cleanup & allow modules to hotplug memory Alastair D'Silva
2019-06-26 6:11 ` [PATCH v2 1/3] mm: Trigger bug on if a section is not found in __section_nr Alastair D'Silva
2019-06-26 6:21 ` Michal Hocko
2019-06-26 6:27 ` Alastair D'Silva
2019-06-26 6:57 ` Michal Hocko
2019-06-27 0:50 ` Alastair D'Silva
2019-06-27 8:10 ` Michal Hocko
2019-06-28 0:46 ` Alastair D'Silva
2019-07-01 10:46 ` Michal Hocko
2019-07-02 4:13 ` Alastair D'Silva
2019-07-02 6:13 ` Michal Hocko
2019-07-02 6:16 ` Alastair D'Silva
2019-06-28 11:37 ` David Hildenbrand
2019-06-28 11:58 ` Michal Hocko
2019-06-26 6:11 ` [PATCH v2 2/3] mm: don't hide potentially null memmap pointer in sparse_remove_one_section Alastair D'Silva
2019-06-26 6:23 ` Michal Hocko
2019-06-26 6:30 ` Alastair D'Silva
2019-06-26 6:59 ` Michal Hocko [this message]
2019-06-28 11:29 ` David Hildenbrand
2019-06-26 6:11 ` [PATCH v2 3/3] mm: Don't manually decrement num_poisoned_pages Alastair D'Silva
2019-06-26 6:24 ` Michal Hocko
2019-06-28 11:29 ` David Hildenbrand
2019-06-26 7:57 ` [PATCH v2 0/3] mm: Cleanup & allow modules to hotplug memory Christoph Hellwig
2019-06-27 0:51 ` Alastair D'Silva
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