linux-kernel - Re: [PATCH v2] memory-hotplug: add automatic onlining policy for the newly added memory

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] [day] [month] [year] [list]

Date:	Mon, 04 Jan 2016 15:28:12 +0100
From:	Vitaly Kuznetsov <vkuznets@...hat.com>
To:	David Vrabel <david.vrabel@...rix.com>
Cc:	<linux-mm@...ck.org>, <linux-doc@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, <xen-devel@...ts.xenproject.org>,
	Jonathan Corbet <corbet@....net>,
	"Greg Kroah-Hartman" <gregkh@...uxfoundation.org>,
	Daniel Kiper <daniel.kiper@...cle.com>,
	Dan Williams <dan.j.williams@...el.com>,
	Tang Chen <tangchen@...fujitsu.com>,
	David Rientjes <rientjes@...gle.com>,
	"Andrew Morton" <akpm@...ux-foundation.org>,
	Naoya Horiguchi <n-horiguchi@...jp.nec.com>,
	Xishi Qiu <qiuxishi@...wei.com>,
	Mel Gorman <mgorman@...hsingularity.net>,
	"K. Y. Srinivasan" <kys@...rosoft.com>,
	"Igor Mammedov" <imammedo@...hat.com>, Kay Sievers <kay@...y.org>,
	"Konrad Rzeszutek Wilk" <konrad.wilk@...cle.com>,
	Boris Ostrovsky <boris.ostrovsky@...cle.com>
Subject: Re: [PATCH v2] memory-hotplug: add automatic onlining policy for the newly added memory

David Vrabel <david.vrabel@...rix.com> writes:

> On 22/12/15 16:32, Vitaly Kuznetsov wrote:
>> @@ -1292,6 +1304,11 @@ int __ref add_memory_resource(int nid, struct resource *res)
>>  	/* create new memmap entry */
>>  	firmware_map_add_hotplug(start, start + size, "System RAM");
>>  
>> +	/* online pages if requested */
>> +	if (online)
>> +		online_pages(start >> PAGE_SHIFT, size >> PAGE_SHIFT,
>> +			     MMOP_ONLINE_KEEP);
>
> This will cause the Xen balloon driver to deadlock because it calls
> add_memory_resource() with the balloon_mutex locked and the online page
> callback also locks the balloon_mutex.

Currently xen ballon driver always calls add_memory_resource() with
online=false so this won't happen.

-- 
  Vitaly
--
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/