Subject: Re: [PATCH v2] of, numa: Return NUMA_NO_NODE from disable
 of_node_to_nid() if nid not possible.
To: Rob Herring <robh+dt@kernel.org>, David Daney <ddaney.cavm@gmail.com>
References: <1477689302-32671-1-git-send-email-ddaney.cavm@gmail.com>
 <CAL_JsqKnXk99SUa1cjC2QFA9rizjn4=JHZh3ua_gvcOtpGx8jg@mail.gmail.com>
CC: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Frank Rowand <frowand.list@gmail.com>,
        "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
        "linux-arm-kernel@lists.infradead.org" 
        <linux-arm-kernel@lists.infradead.org>,
        Will Deacon <will.deacon@arm.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Robert Richter <rric@kernel.org>, Hanjun Guo <hanjun.guo@linaro.org>,
        Ganapatrao Kulkarni <gkulkarni@caviumnetworks.com>,
        Gilbert Netzer <noname@pdc.kth.se>,
        David Daney <david.daney@cavium.com>
From: David Daney <ddaney@caviumnetworks.com>
Message-ID: <93b7769a-4907-176e-9f18-0bf6bd72d15d@caviumnetworks.com>
Date: Thu, 3 Nov 2016 08:11:05 -0700
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On 11/02/2016 08:37 PM, Rob Herring wrote:
> On Fri, Oct 28, 2016 at 4:15 PM, David Daney <ddaney.cavm@gmail.com> wrote:
>> From: David Daney <david.daney@cavium.com>
>>
>> On arm64 NUMA kernels we can pass "numa=off" on the command line to
>> disable NUMA.  A side effect of this is that kmalloc_node() calls to
>> non-zero nodes will crash the system with an OOPS:
>>
>> [    0.000000] ITS@0x0000901000020000: allocated 2097152 Devices @10002000000 (flat, esz 8, psz 64K, shr 1)
>> [    0.000000] Unable to handle kernel NULL pointer dereference at virtual address 00001680
>> [    0.000000] pgd = fffffc0009470000
>> [    0.000000] [00001680] *pgd=0000010ffff90003, *pud=0000010ffff90003, *pmd=0000010ffff90003, *pte=0000000000000000
>> [    0.000000] Internal error: Oops: 96000006 [#1] SMP
>> .
>> .
>> .
>> [    0.000000] [<fffffc00081c8950>] __alloc_pages_nodemask+0xa4/0xe68
>> [    0.000000] [<fffffc000821fa70>] new_slab+0xd0/0x564
>> [    0.000000] [<fffffc0008221e24>] ___slab_alloc+0x2e4/0x514
>> [    0.000000] [<fffffc0008239498>] __slab_alloc+0x48/0x58
>> [    0.000000] [<fffffc0008222c20>] __kmalloc_node+0xd0/0x2dc
>> [    0.000000] [<fffffc0008115374>] __irq_domain_add+0x7c/0x164
>> [    0.000000] [<fffffc0008b461dc>] its_probe+0x784/0x81c
>> [    0.000000] [<fffffc0008b462bc>] its_init+0x48/0x1b0
>> [    0.000000] [<fffffc0008b4543c>] gic_init_bases+0x228/0x360
>> [    0.000000] [<fffffc0008b456bc>] gic_of_init+0x148/0x1cc
>> [    0.000000] [<fffffc0008b5aec8>] of_irq_init+0x184/0x298
>> [    0.000000] [<fffffc0008b43f9c>] irqchip_init+0x14/0x38
>> [    0.000000] [<fffffc0008b12d60>] init_IRQ+0xc/0x30
>> [    0.000000] [<fffffc0008b10a3c>] start_kernel+0x240/0x3b8
>> [    0.000000] [<fffffc0008b101c4>] __primary_switched+0x30/0x6c
>> [    0.000000] Code: 912ec2a0 b9403809 0a0902fb 37b007db (f9400300)
>> .
>> .
>> .
>>
>> This is caused by code like this in kernel/irq/irqdomain.c
>>
>>     domain = kzalloc_node(sizeof(*domain) + (sizeof(unsigned int) * size),
>>                   GFP_KERNEL, of_node_to_nid(of_node));
>>
>> When NUMA is disabled, the concept of a node is really undefined, so
>> of_node_to_nid() should unconditionally return NUMA_NO_NODE.
>>
>> Fix by returning NUMA_NO_NODE when the nid is not in the set of
>> possible nodes.
>>
>> Reported-by: Gilbert Netzer <noname@pdc.kth.se>
>> Signed-off-by: David Daney <david.daney@cavium.com>
>
> Does this need to go in 4.9?

That would be my preference.

> stable? If so, since what kernel version?
>

v4.7 and later would be nice.

I guess if you merge it, you could add the Cc: stable@ tag


Thanks for looking at this,
David Daney