Date: Mon, 27 Jul 2015 11:59:51 +0100
From: Mel Gorman <mgorman@suse.de>
To: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
        Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>,
        Pekka Enberg <penberg@kernel.org>, Paul McQuade <paulmcquad@gmail.com>,
        Tang Chen <tangchen@cn.fujitsu.com>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] bootmem: avoid freeing to bootmem after bootmem is done
Message-ID: <20150727105951.GO2561@suse.de>
References: <1437771226-31255-1-git-send-email-cmetcalf@ezchip.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-15
Content-Disposition: inline
In-Reply-To: <1437771226-31255-1-git-send-email-cmetcalf@ezchip.com>
User-Agent: Mutt/1.5.21 (2010-09-15)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1085
Lines: 25

On Fri, Jul 24, 2015 at 04:53:46PM -0400, Chris Metcalf wrote:
> Bootmem isn't popular any more, but some architectures still use
> it, and freeing to bootmem after calling free_all_bootmem_core()
> can end up scribbling over random memory.  Instead, make sure the
> kernel panics by ensuring the node_bootmem_map field is non-NULL
> when are freeing or marking bootmem.
> 
> An instance of this bug was just fixed in the tile architecture
> ("tile: use free_bootmem_late() for initrd") and catching this case
> more widely seems like a good thing.
> 
> Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>

In general it looks fine  but you could just WARN_ON, return and still
boot the kernel too. Obviously it would need to be fixed but Linus will
push back if he spots a BUG_ON when there was a recovery option.

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