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From: Pavel Tatashin <pasha.tatashin@oracle.com>
To: Sasha Levin <Alexander.Levin@microsoft.com>
Cc: "steven.sistare@oracle.com" <steven.sistare@oracle.com>,
	"daniel.m.jordan@oracle.com" <daniel.m.jordan@oracle.com>,
	"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
	"mgorman@techsingularity.net" <mgorman@techsingularity.net>,
	"mhocko@suse.com" <mhocko@suse.com>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
	"vbabka@suse.cz" <vbabka@suse.cz>,
	"bharata@linux.vnet.ibm.com" <bharata@linux.vnet.ibm.com>
Subject: Re: [PATCH v2 1/2] mm: uninitialized struct page poisoning sanity checking
Date: Tue, 13 Mar 2018 21:02:53 -0400	[thread overview]
Message-ID: <CAGM2reYo2EbH0W70rJGSGWRBAO=upcNDanBoCQgve+eQ_94C8A@mail.gmail.com> (raw)
In-Reply-To: <20180314005350.6xdda2uqzuy4n3o6@sasha-lappy>

On Tue, Mar 13, 2018 at 8:53 PM, Sasha Levin
<Alexander.Levin@microsoft.com> wrote:
> On Tue, Mar 13, 2018 at 08:38:57PM -0400, Pavel Tatashin wrote:
>>Hi Sasha,
>>
>>It seems the patch is doing the right thing, and it catches bugs. Here
>>we access uninitialized struct page. The question is why this happens?
>
> Not completely; note that we die on an invalid reference rather than
> assertion failure.

I think that invalid reference happens within assertion failure, as
far as I can tell, it is dump_page() where we get the invalid
reference, but to get to dump_page() from get_nid_for_pfn() we must
have triggered the assertion.

>
>>register_mem_sect_under_node(struct memory_block *mem_blk, int nid)
>>   page_nid = get_nid_for_pfn(pfn);
>>
>>node id is stored in page flags, and since struct page is poisoned,
>>and the pattern is recognized, the panic is triggered.
>>
>>Do you have config file? Also, instructions how to reproduce it?
>
> Attached the config. It just happens on boot.

Thanks, I will try in qemu.

Pasha

  reply	other threads:[~2018-03-14  1:02 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-31 21:02 [PATCH v2 0/2] optimize memory hotplug Pavel Tatashin
2018-01-31 21:02 ` [PATCH v2 1/2] mm: uninitialized struct page poisoning sanity checking Pavel Tatashin
2018-02-02  4:12   ` kbuild test robot
2018-03-13 23:43   ` Sasha Levin
2018-03-14  0:38     ` Pavel Tatashin
2018-03-14  0:53       ` Sasha Levin
2018-03-14  1:02         ` Pavel Tatashin [this message]
2018-03-15 19:04         ` Pavel Tatashin
2018-03-15 20:43           ` Sasha Levin
2018-04-04  2:17             ` Pavel Tatashin
2018-04-05 13:49               ` Pavel Tatashin
2018-04-05 19:22                 ` Sasha Levin
2018-04-06 12:45                   ` Pavel Tatashin
2018-04-07 14:45                     ` Pavel Tatashin
2018-01-31 21:03 ` [PATCH v2 2/2] mm, memory_hotplug: optimize memory hotplug Pavel Tatashin
2018-02-02  4:48   ` kbuild test robot

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