From: Vlastimil Babka <vbabka@suse.cz>
To: Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
Michael Ellerman <mpe@ellerman.id.au>
Cc: Sachin Sant <sachinp@linux.vnet.ibm.com>,
Michal Hocko <mhocko@kernel.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Pekka Enberg <penberg@kernel.org>,
Linux-Next Mailing List <linux-next@vger.kernel.org>,
David Rientjes <rientjes@google.com>,
Christopher Lameter <cl@linux.com>,
linuxppc-dev@lists.ozlabs.org,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Kirill Tkhai <ktkhai@virtuozzo.com>
Subject: Re: [5.6.0-rc2-next-20200218/powerpc] Boot failure on POWER9
Date: Fri, 13 Mar 2020 12:35:33 +0100 [thread overview]
Message-ID: <11e69587-8b64-6088-cb5c-d7d719842535@suse.cz> (raw)
In-Reply-To: <20200313111246.GB25144@linux.vnet.ibm.com>
On 3/13/20 12:12 PM, Srikar Dronamraju wrote:
> * Michael Ellerman <mpe@ellerman.id.au> [2020-03-13 21:48:06]:
>
>> Sachin Sant <sachinp@linux.vnet.ibm.com> writes:
>> >> The patch below might work. Sachin can you test this? I tried faking up
>> >> a system with a memoryless node zero but couldn't get it to even start
>> >> booting.
>> >>
>> > The patch did not help. The kernel crashed during
>> > the boot with the same call trace.
>> >
>> > BUG_ON() introduced with the patch was not triggered.
>>
>> OK, that's weird.
>>
>> I eventually managed to get a memoryless node going in sim, and it
>> appears to work there.
>>
>> eg in dmesg:
>>
>> [ 0.000000][ T0] numa: NODE_DATA [mem 0x2000fffa2f80-0x2000fffa7fff]
>> [ 0.000000][ T0] numa: NODE_DATA(0) on node 1
>> [ 0.000000][ T0] numa: NODE_DATA [mem 0x2000fff9df00-0x2000fffa2f7f]
>> ...
>> [ 0.000000][ T0] Early memory node ranges
>> [ 0.000000][ T0] node 1: [mem 0x0000000000000000-0x00000000ffffffff]
>> [ 0.000000][ T0] node 1: [mem 0x0000200000000000-0x00002000ffffffff]
>> [ 0.000000][ T0] Could not find start_pfn for node 0
>> [ 0.000000][ T0] Initmem setup node 0 [mem 0x0000000000000000-0x0000000000000000]
>> [ 0.000000][ T0] On node 0 totalpages: 0
>> [ 0.000000][ T0] Initmem setup node 1 [mem 0x0000000000000000-0x00002000ffffffff]
>> [ 0.000000][ T0] On node 1 totalpages: 131072
>>
>> # dmesg | grep set_numa
>> [ 0.000000][ T0] set_numa_mem: mem node for 0 = 1
>> [ 0.005654][ T0] set_numa_mem: mem node for 1 = 1
>>
>> So is the problem more than just node zero having no memory?
>>
>
> The problem would happen with possible nodes which are not yet present. i.e
> no cpus, no memory attached to those nodes.
>
> Please look at
> http://lore.kernel.org/lkml/20200312131438.GB3277@linux.vnet.ibm.com/t/#u
> for more details.
>
> The summary being: pgdat/Node_Data for such nodes is not allocated. Hence
Michael's log shows that his pgdat is still allocated. But perhaps Sachin had
also your 3 patches from the other thread applied, in addition to Michael's
patch. So in his case pgdat for node 0 would indeed be no longer allocated, and
thus SLUB code was crashing in node_present_pages() instead.
> the node_present_pages(nid) called where nid is a possible but not yet
> present node fails. Currently node_present_pages(nid) and node_to_mem_node
> don't seem to be equipped to handle possible but not present nodes.
>
>> cheers
>
next prev parent reply other threads:[~2020-03-13 11:35 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-18 10:45 [5.6.0-rc2-next-20200218/powerpc] Boot failure on POWER9 Sachin Sant
2020-02-18 10:50 ` Kirill Tkhai
2020-02-18 11:01 ` Kirill Tkhai
2020-02-18 11:35 ` Kirill Tkhai
2020-02-18 11:40 ` Sachin Sant
2020-02-18 11:55 ` Michal Hocko
2020-02-18 14:00 ` Sachin Sant
2020-02-18 14:26 ` Michal Hocko
2020-02-18 15:11 ` Sachin Sant
2020-02-18 15:24 ` Michal Hocko
2020-02-22 3:38 ` Christopher Lameter
2020-02-24 8:58 ` Michal Hocko
2020-02-26 18:25 ` Christopher Lameter
2020-02-26 18:41 ` Michal Hocko
2020-02-26 18:44 ` Christopher Lameter
2020-02-26 19:01 ` Michal Hocko
2020-02-26 20:31 ` David Rientjes
2020-02-26 20:52 ` Michal Hocko
2020-02-26 21:45 ` Vlastimil Babka
2020-02-26 22:29 ` Vlastimil Babka
2020-02-27 12:12 ` Michal Hocko
2020-02-27 16:00 ` Sachin Sant
2020-02-27 16:16 ` Vlastimil Babka
2020-02-27 18:26 ` Michal Hocko
2020-03-10 15:01 ` Michal Hocko
2020-03-12 12:18 ` Michael Ellerman
2020-03-12 16:51 ` Sachin Sant
2020-03-13 10:48 ` Michael Ellerman
2020-03-13 11:12 ` Srikar Dronamraju
2020-03-13 11:35 ` Vlastimil Babka [this message]
2020-03-14 8:10 ` Sachin Sant
2020-02-27 12:02 ` Michal Hocko
2020-02-18 11:38 ` Sachin Sant
2020-02-18 11:53 ` Kirill Tkhai
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