The watchpoint plus Canary's source settle it. At the write, the guest context
(rsi, per x64_emitter.cc:881) holds 0x8226EAE0, inside sub_8226EAB8. That
function is a generic list-node insert: it reads the count at 8(r30), guards
against 0x3FFFFFFF overflow, does addi r11,r11,1 / stw r11,8(r30), then links the
node. It has 16 callers, so it is a shared container helper.
That explains why two static searches missed it. The trigger container at
phase+272 EMBEDS an inner list object at +12 -- which is why the push does
'addi r31, r30, 12' -- and the inner object keeps its count at its own +8. So
272 + 12 + 8 = 292 = the watched word, and the instruction is stw r11, 8(r30)
with r30 = phase+284. Searching for 'stw rN, 20(rM)' could never have found it.
Also resolves the earlier open item on +12: it is the embedded list object, not
a list head pointer, which is why it read 0x000A0009 instead of an address.
Method note kept: the static hunt assumed the field's offset in the OUTER object
would appear in the writing instruction. A watchpoint is indifferent to the
addressing form, which is why it was the right tool after two failed offset
searches.
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