Re: port-amd64/60920: 11.0 kernel for amd64 fails with null pointer deref in uvm_page_redim()

[Havard Eidnes <he%NetBSD.org@localhost>]

>  >So bucketcount = 2, at least in 10.0?
>
>  bucketcount = 2 is a problem if the code touches bucket 2
>  (only 0 + 1 exist).

Well, there's a difference between "index" and "count"; one would
say that one has 2 buckets if they're indexed with 0 and 1, no?

If uvm.bucketcount = newnbuckets = 2, (whatever % newnbuckets)
will be either 0 or 1, no?  So are we getting to the crash via

                      if (uvm_page_numa_region != NULL) {
                              nb = uvm_page_numa_lookup(pg);

?

# crash
Crash version 10.0, image version 10.0.
Kernel compiled without options LOCKDEBUG.
Output from a running system is unreliable.
crash> x/x uvm_page_numa_region
uvm_page_numa_region:   da530c80
crash> 

I'll note that I don't quite understand why the last 4 cores are
noted as "node 1" whereas the 4 first in the last package are
"node 0", in

: {33} cat /tmp/11-cpus  | egrep 'cpu.*node'
[   1.0000000] cpu0: node 0, package 0, core 0, smt 0
[   1.0000000] cpu1: node 0, package 0, core 1, smt 0
[   1.0000000] cpu2: node 0, package 0, core 2, smt 0
[   1.0000000] cpu3: node 0, package 0, core 3, smt 0
[   1.0000000] cpu4: node 0, package 0, core 4, smt 0
[   1.0000000] cpu5: node 0, package 0, core 5, smt 0
[   1.0000000] cpu6: node 0, package 0, core 6, smt 0
[   1.0000000] cpu7: node 0, package 0, core 7, smt 0
[   1.0000000] cpu8: node 0, package 1, core 0, smt 0
[   1.0000000] cpu9: node 0, package 1, core 1, smt 0
[   1.0000000] cpu10: node 0, package 1, core 2, smt 0
[   1.0000000] cpu11: node 0, package 1, core 3, smt 0
[   1.0000000] cpu12: node 1, package 1, core 4, smt 0
[   1.0000000] cpu13: node 1, package 1, core 5, smt 0
[   1.0000000] cpu14: node 1, package 1, core 6, smt 0
[   1.0000000] cpu15: node 1, package 1, core 7, smt 0
: {34} 

(That's the same with 10.0)

Regards,

- Havard