linux-kernel - Re: [PATCH 04/12] mm: alloc_contig_freed

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: <1301603619.31087.1203.camel@nimitz>
Date:	Thu, 31 Mar 2011 13:33:39 -0700
From:	Dave Hansen <dave@...ux.vnet.ibm.com>
To:	Steven Rostedt <rostedt@...dmis.org>
Cc:	Marek Szyprowski <m.szyprowski@...sung.com>,
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-samsung-soc@...r.kernel.org, linux-media@...r.kernel.org,
	linux-mm@...ck.org, Michal Nazarewicz <mina86@...a86.com>,
	Kyungmin Park <kyungmin.park@...sung.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
	Ankita Garg <ankita@...ibm.com>,
	Daniel Walker <dwalker@...eaurora.org>,
	Johan MOSSBERG <johan.xx.mossberg@...ricsson.com>,
	Mel Gorman <mel@....ul.ie>, Pawel Osciak <pawel@...iak.com>
Subject: Re: [PATCH 04/12] mm: alloc_contig_freed_pages() added

On Thu, 2011-03-31 at 15:24 -0400, Steven Rostedt wrote:
> On Thu, Mar 31, 2011 at 08:58:03AM -0700, Dave Hansen wrote:
> > On Thu, 2011-03-31 at 15:16 +0200, Marek Szyprowski wrote:
> > > 
> > > +unsigned long alloc_contig_freed_pages(unsigned long start, unsigned long end,
> > > +                                      gfp_t flag)
> > > +{
> > > +       unsigned long pfn = start, count;
> > > +       struct page *page;
> > > +       struct zone *zone;
> > > +       int order;
> > > +
> > > +       VM_BUG_ON(!pfn_valid(start));
> > 
> > This seems kinda mean.  Could we return an error?  I understand that
> > this is largely going to be an early-boot thing, but surely trying to
> > punt on crappy input beats a full-on BUG().
> > 
> > 	if (!pfn_valid(start))
> > 		return -1;
> 
> But still keep the warning?
> 
> 	if (WARN_ON(!pfn_valid(start))
> 		return -1;

Sure.  You might also want to make sure you're respecting __GFP_NOWARN
if you're going to do that, or maybe just warn once per boot.


-- Dave

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/