nx2: notes on the 100 MiB ColPaintBuild failure behind the recurring crash

1 files changed, 1 insertions, 0 deletions

diff --git a/NX2_NOTES.md b/NX2_NOTES.md
index a02fb39795..a1f6bc49d0 100644
--- a/NX2_NOTES.md
+++ b/NX2_NOTES.md
@@ -134,6 +134,7 @@ With the patched decoder, games 1/3/4 only leave ~60-110 rare SIMD encodings in
 | 76 | debugger run, crash at 406 s in the same scene load: writes through a null result at pc 0x82b471fc (main+0x2b271fc) | the scene's frame heap "PaintSceneProcHeap.26" (fixed 90 MiB + 0xfc8 parent, head 0x12c9525d18, tail 0x12c9800208) had 2.98 MB left for a 0x302088 allocation (A init main+0x2b37de0 -> main+0x2b27020); about 160 KB short, so some allocation of that scene is bigger than on the console (only 11.7 MB of the heap is nx2:gpu memory); the main thread was waiting in svc 0x34 for job workers | open: log that heap's allocations to find the oversized one |
 | 77 | why the scene heap overflowed (run 6) | the heap size is a constant (mov w1, #0x5a00000 at main+0x2b32070); its fixed contents are 71.3 MiB (main+0x2ab9218) + 1.05 MiB + 1.25 MiB + 3 MiB; in runs 3, 4, 5 and the save test the scene's two 0x514000 GPU pools come from the root heap (next to the 0x2ee000 pool), in run 6 from the scene heap (current heap of the loading thread), 10 MiB it has no room for; which heap a job allocates from depends on the thread running it. The game's npdm asks for cores 0..5 (mask 0x3f, reported as is by GetInfo CoreMask) and Eden folds 4, 5 onto 0, 1, so two cores run two workers each | candidate: report or emulate the real core layout; ruled out: memory layout (12 GB), controllers (one), GPU pool alignment |
 | 78 | six emulated cores (4fbfd5b), run 7 with the gdbstub: same scene-heap overflow at 292 s, the 0x514000 pools again in the scene heap | both overflow runs (6, 7) had the gdbstub on (memory accesses checked, slower JIT); the three runs without it (3, 4, 5) put those pools in the root heap and crashed later on the torn-down object instead, so the debugger itself shifts this timing | open: a six-core run without the gdbstub |
+| 79 | run 8 (six cores, no gdbstub): original crash at 338.6 s, 11 s after the paint scene set up (327 s, pools in the root heap) | C's init (main+0x2ab9120) creates "ColPaintBuild.%u" (main+0x147d3c0 -> main+0x34f3850) sized by [C+0x738], 100 MiB by default (ctor main+0x2ab874c); when that returns null, init returns before setting [C+0x720], and the next state request (main+0x2aba230) crashes the update. So every crash at this load is a memory shortage: 100 MiB (no gdbstub) or 3 MiB in the scene heap (gdbstub). Root heap is 0x19506f000 at 0x1145e10020 | open: why memory is short (reported total memory for Switch 2, frees delayed behind the GPU) |
 
 Run settings used (in `build/bin/user/config/sdl2-config.ini`): `memory_layout_mode=4`
 (12 GB). Debug knobs: `EDEN_NX2_AUTO_STUB`, `EDEN_NX2_IPC_TRACE`, `EDEN_NX2_SVC_TRACE`,