Re: [PATCH v3 2/2] mm/page_alloc: fix memmap_init_zone pageblock alignment

[Daniel Vacek]

On Mon, Mar 12, 2018 at 3:49 PM, Naresh Kamboju
<naresh.kamboju@xxxxxxxxxx> wrote:
> On 12 March 2018 at 17:56, Sudeep Holla <sudeep.holla@xxxxxxx> wrote:
>> Hi,
>>
>> I couldn't find the exact mail corresponding to the patch merged in v4.16-rc5
>> but commit 864b75f9d6b01 "mm/page_alloc: fix memmap_init_zone
>> pageblock alignment"
>> cause boot hang on my ARM64 platform.
>
> I have also noticed this problem on hi6220 Hikey - arm64.
>
> LKFT: linux-next: Hikey boot failed linux-next-20180308
> https://bugs.linaro.org/show_bug.cgi?id=3676
>
> - Naresh
>
>>
>> Log:
>> [    0.000000] NUMA: No NUMA configuration found
>> [    0.000000] NUMA: Faking a node at [mem
>> 0x0000000000000000-0x00000009ffffffff]
>> [    0.000000] NUMA: NODE_DATA [mem 0x9fffcb480-0x9fffccf7f]
>> [    0.000000] Zone ranges:
>> [    0.000000]   DMA32    [mem 0x0000000080000000-0x00000000ffffffff]
>> [    0.000000]   Normal   [mem 0x0000000100000000-0x00000009ffffffff]
>> [    0.000000] Movable zone start for each node
>> [    0.000000] Early memory node ranges
>> [    0.000000]   node   0: [mem 0x0000000080000000-0x00000000f8f9afff]
>> [    0.000000]   node   0: [mem 0x00000000f8f9b000-0x00000000f908ffff]
>> [    0.000000]   node   0: [mem 0x00000000f9090000-0x00000000f914ffff]
>> [    0.000000]   node   0: [mem 0x00000000f9150000-0x00000000f920ffff]
>> [    0.000000]   node   0: [mem 0x00000000f9210000-0x00000000f922ffff]
>> [    0.000000]   node   0: [mem 0x00000000f9230000-0x00000000f95bffff]
>> [    0.000000]   node   0: [mem 0x00000000f95c0000-0x00000000fe58ffff]
>> [    0.000000]   node   0: [mem 0x00000000fe590000-0x00000000fe5cffff]
>> [    0.000000]   node   0: [mem 0x00000000fe5d0000-0x00000000fe5dffff]
>> [    0.000000]   node   0: [mem 0x00000000fe5e0000-0x00000000fe62ffff]
>> [    0.000000]   node   0: [mem 0x00000000fe630000-0x00000000feffffff]
>> [    0.000000]   node   0: [mem 0x0000000880000000-0x00000009ffffffff]
>> [    0.000000]  Initmem setup node 0 [mem 0x0000000080000000-0x00000009ffffffff]
>>
>> On Sat, Mar 3, 2018 at 1:08 AM, Daniel Vacek <neelx@xxxxxxxxxx> wrote:
>>> On Sat, Mar 3, 2018 at 1:40 AM, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
>>>>
>>>> This makes me wonder whether a -stable backport is really needed...
>>>
>>> For some machines it definitely is. Won't hurt either, IMHO.
>>>
>>> --nX

Hmm, does it step back perhaps?

Can you check if below cures the boot hang?

--nX

~~~~
neelx@metal:~/nX/src/linux$ git diff
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 3d974cb2a1a1..415571120bbd 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5365,8 +5365,10 @@ void __meminit memmap_init_zone(unsigned long
size, int nid, unsigned long zone,
                         * the valid region but still depends on correct page
                         * metadata.
                         */
-                       pfn = (memblock_next_valid_pfn(pfn, end_pfn) &
+                       unsigned long next_pfn;
+                       next_pfn = (memblock_next_valid_pfn(pfn, end_pfn) &
                                        ~(pageblock_nr_pages-1)) - 1;
+                       pfn = max(next_pfn, pfn);
 #endif
                        continue;
                }
~~~~