Re: [PATCH v3] mm: fix panic in __alloc_pages

On Dec 9, 2021, at 1:56 AM, Michal Hocko [off-list ref] wrote:

On Thu 09-12-21 09:28:55, Alexey Makhalov wrote:

quoted

[    0.081777] Node 4 uninitialized by the platform. Please report with boot dmesg.
[    0.081790] Initmem setup node 4 [mem 0x0000000000000000-0x0000000000000000]
...
[    0.086441] Node 127 uninitialized by the platform. Please report with boot dmesg.
[    0.086454] Initmem setup node 127 [mem 0x0000000000000000-0x0000000000000000]

Interesting that only those two didn't get a proper arch specific
initialization. Could you check why? I assume init_cpu_to_node
doesn't see any CPU pointing at this node. Wondering why that would be
the case but that can be a bug in the affinity tables.

My bad shrinking. Not just these 2, but all possible and not present nodes from 4 to 127
are having this message.

quoted

vCPU/node hot add works.
Onlining works as well, but with warning. I do not think it is related to the patch:
[   36.838838] CPU4 has been hot-added
[   36.838987] acpi_processor_hotadd_init:205 cpu 4, node 4, online 0, ndata 00000000e9c7f79b
[   48.480498] Built 4 zonelists, mobility grouping on.  Total pages: 961440
[   48.480508] Policy zone: Normal
[   48.508318] smpboot: Booting Node 4 Processor 4 APIC 0x8
[   48.509255] Disabled fast string operations
[   48.509807] smpboot: CPU 4 Converting physical 8 to logical package 4
[   48.509825] smpboot: CPU 4 Converting physical 0 to logical die 4
[   48.510040] WARNING: workqueue cpumask: online intersect > possible intersect

I will double check. There are changes required on the hotplug side. I
would like to see that this one doesn't blow up before diving there.

quoted

[   48.510324] vmware: vmware-stealtime: cpu 4, pa 3e667000
[   48.511311] Will online and init hotplugged CPU: 4

Hot remove does not quite work. It might be issue in ACPI/Firmware code or Hypervisor. Debugging…

Do you want me to perform any specific tests?

No, not really. AFAIU your issue has been reproducible during boot and
that seems to be fixed. I will work on the hotplug side of the things
and post something resembling a real patch soon. That would require also
memory hotplug testing.

I can help you with memory hotplug testing if needed.

Thanks,
—Alexey