Re: [5.6.0-rc2-next-20200218/powerpc] Boot failure on POWER9

On 13-Mar-2020, at 5:05 PM, Vlastimil Babka [off-list ref] wrote:

On 3/13/20 12:12 PM, Srikar Dronamraju wrote:

quoted

* Michael Ellerman [off-list ref] [2020-03-13 21:48:06]:

quoted

Sachin Sant [off-list ref] writes:

quoted

quoted

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?

I tried with just the patch Michael suggested on top of March 13 next tree.
I still see the same failure. Here is a snippet from the log

[    0.000000] numa:   NODE_DATA [mem 0x8bfedc900-0x8bfee3fff]
[    0.000000] numa:     NODE_DATA(0) on node 1
[    0.000000] numa:   NODE_DATA [mem 0x8bfed5200-0x8bfedc8ff]
[    0.000000] rfi-flush: fallback displacement flush available
[    0.000000] rfi-flush: mttrig type flush available
[    0.000000] link-stack-flush: software flush enabled.
[    0.000000] count-cache-flush: software flush disabled.
[    0.000000] stf-barrier: eieio barrier available
[    0.000000] lpar: H_BLOCK_REMOVE supports base psize:0 psize:0 block size:8
[    0.000000] lpar: H_BLOCK_REMOVE supports base psize:0 psize:2 block size:8
[    0.000000] lpar: H_BLOCK_REMOVE supports base psize:0 psize:10 block size:8
[    0.000000] lpar: H_BLOCK_REMOVE supports base psize:2 psize:2 block size:8
[    0.000000] lpar: H_BLOCK_REMOVE supports base psize:2 psize:10 block size:8
[    0.000000] PPC64 nvram contains 15360 bytes
[    0.000000] barrier-nospec: using ORI speculation barrier
[    0.000000] Zone ranges:
[    0.000000]   Normal   [mem 0x0000000000000000-0x00000008bfffffff]
[    0.000000]   Device   empty
[    0.000000] Movable zone start for each node
[    0.000000] Early memory node ranges
[    0.000000]   node   1: [mem 0x0000000000000000-0x00000008bfffffff]
[    0.000000] Could not find start_pfn for node 0
[    0.000000] Initmem setup node 0 [mem 0x0000000000000000-0x0000000000000000]
[    0.000000] Initmem setup node 1 [mem 0x0000000000000000-0x00000008bfffffff]
[    0.000000] percpu: Embedded 11 pages/cpu s624024 r0 d96872 u1048576
[    0.000000] Built 2 zonelists, mobility grouping on.  Total pages: 572880

Have attached the complete boot log.

Thanks
-Sachin