[Toybox] top -H segfault

[enh]

just running home, so no time to debug further, but in case you
haven't seen this yet... plain "top -H" is segfaulting for me before
displaying anything.

/tmp/toybox$ gdb --args ./generated/unstripped/toybox top -H
...
(gdb) run
Starting program: /tmp/toybox/generated/unstripped/toybox top -H
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/usr/grte/v4/lib64/libthread_db.so.1".

Program received signal SIGSEGV, Segmentation fault.
                                                    0x00000000004219c1
in top_common (filter=filter at entry=0x41f738 <merge_deltas>) at
toys/posix/ps.c:1349
1349      if (old.count && (!new.count || *otb->slot < *ntb->slot)) {
(gdb) inf loc
otb = 0x0
ntb = 0x0
dt = <optimized out>
recalc = 1
timeout = 0
now = <optimized out>
stats = {730451913, 22228303, 322430278, 37782074954, 2668971, 6366,
2187247, 0, 730451888, 22228303, 322430265, 37782073147,
  2668971, 6366, 2187247, 0}
plist = {{tb = 0xa5ef00, count = 3218, whence = 8115186216}, {tb =
0x644870, count = 3218, whence = 8115185836}}
plold = 0x7fffffffdc70
plnew = 0x7fffffffdc58
old = {tb = 0x644870, count = 3218, whence = <optimized out>}
new = {tb = 0xa5ef00, count = 3218, whence = <optimized out>}
mix = {tb = 0x7ffff6034010, count = 0, whence = <optimized out>}
scratch = "\000\000\000\000\000\000\000\000\060\000\000\000\377\177\000"
pos = <optimized out>
cpufields = {0x437610 "user", 0x436c1e "nice", 0x439ff0 "sys",
0x438c7d "idle", 0x43b2ba "iow", 0x43b2bf "irq",
  0x43b2be "sirq", 0x4373cd "host"}
tock = 2
i = <optimized out>
lines = <optimized out>
topoff = 0
done = 0
(gdb)