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* r481c sema_push_raw: lower the call-site threshold to 512 bytes so launch ↵Arthur Hanson Rasmusson10 hours
| | | | pushes (872/888B) dump; runtime-enable before the client run to avoid boot noise
* r481b sema_push_raw walk fix: handle op!=1 method groups (data runs, scans) ↵Arthur Hanson Rasmusson10 hours
| | | | and bound to launch-sized pushes (512..8192 bytes) so the launch method stream dumps cleanly
* r481 sema_push_raw diagnostic: dump the decoded method stream of the first N ↵Arthur Hanson Rasmusson10 hours
| | | | large GR-class pushes (default 0 off, no behaviour change) so the launch push's acquire/release method groups are visible verbatim; needed to prove which ordering mechanism the driver relies on for async-stream H2D -> kernel dependencies (streams_events st2 vadd copy-in ran ~115 ms before its stream's H2D soft copies)
* r471 the counter-publish clamp: never advance the guest's completion word ↵Arthur Hanson Rasmusson11 hours
| | | | past a push whose content was still unwritten when its entry was consumed. The r477 failing probe run showed the reuse hazard directly: the channel registered with a residual USERD put (4) and ring slots 1-3 all-zero; the pump consumed them (the r470 hold only delays) and the end-of-pass publish then wrote val=2 while the client's own counter was still 1 - the D2H wait was satisfied before the copy ran and the readback drained a reused staging buffer holding the PREVIOUS copy's bytes (h_c[2] = c0's data). New per-channel gr_bad_put (lowest all-zero GR slot + 1, persisted in the pump write-back): set when a zero-content GR entry is held/consumed, cleared when a decode reads non-zero content (the rewinds re-read entries constantly, so it heals within passes); svc_counter_publish clamps val to it with a bounded pub-clamp witness.
* r470 the narrow streams_events stale-ring fix: an ALL-ZERO push page (ring ↵Arthur Hanson Rasmusson12 hours
| | | | entry written - previous session's or the client's own slot reuse - but the push content not yet landed) is held by the m164 GR no-capture window instead of being consumed as a no-op, so the end-of-pass counter publish cannot advance the guest's completion word before the real push is read (streams_events: h_c[2] = c0 because the c2 D2H completion was published 4.5 s before its copy ran). Deliberately narrower than the reverted r469 plausibility verdict: compute-class GR pushes legitimately fail the CE-shaped method matcher, so only an entirely zero page counts as unwritten (r469's broad hold delayed GR config pushes and triggered the engine-fetch-NONE wedge on the first client).
* Revert "r469 THE streams_events staging-reuse corruption root cause: a GR ↵Arthur Hanson Rasmusson12 hours
| | | | | | entry whose push content is implausible (unwritten / previous-epoch page, no QMD word seen) was consumed as a no-op and the end-of-pass counter publish then advanced the guest's completion word while the real push had never been read - the client drained a staging buffer that still held the PREVIOUS copy's bytes (probe run: BUF s=2 got=c0's 0,0.75,1.5.. instead of c2's 3.0,5.25,7.5..; log: 'pub-adv h=0x5c000062 val=4 cur=1' at 210741.947, 4.5 s before the c2 D2H copy executed at 210746.371, with the ring slots decoded as zero-content pushes at 210736). The implausible-content read now feeds the m164 GR no-capture hold (bounded gsp_sema_gr_nocap_hold_ms window, rehold forces a fresh capture): the entry stays unconsumed, the publish gate (last_get != put) suppresses the early completion, and the retry reads the client's real push once it lands. Plausible fallback reads (validated pin / displaced pair) clear the flag." This reverts commit 349ee341539a0c1e9e3be11563251589eb42f8a8.
* r469 THE streams_events staging-reuse corruption root cause: a GR entry ↵Arthur Hanson Rasmusson12 hours
| | | | whose push content is implausible (unwritten / previous-epoch page, no QMD word seen) was consumed as a no-op and the end-of-pass counter publish then advanced the guest's completion word while the real push had never been read - the client drained a staging buffer that still held the PREVIOUS copy's bytes (probe run: BUF s=2 got=c0's 0,0.75,1.5.. instead of c2's 3.0,5.25,7.5..; log: 'pub-adv h=0x5c000062 val=4 cur=1' at 210741.947, 4.5 s before the c2 D2H copy executed at 210746.371, with the ring slots decoded as zero-content pushes at 210736). The implausible-content read now feeds the m164 GR no-capture hold (bounded gsp_sema_gr_nocap_hold_ms window, rehold forces a fresh capture): the entry stays unconsumed, the publish gate (last_get != put) suppresses the early completion, and the retry reads the client's real push once it lands. Plausible fallback reads (validated pin / displaced pair) clear the flag.
* r459 THE mid-boot degradation root cause: the 8-slot VA-space table filled ↵Arthur Hanson Rasmusson14 hours
| | | | | | | | | | | | | | | | | | | | | | | | | | with dead clients' registrations and every new client after the 8th got no slot Evidence (r466 boot, one battery): 23 distinct 'VA space 0x... page directory ... entries=4' registrations and ZERO 'VA space ... dropped' lines. The guest driver does not always tear a client's VA space down (client exit, crash, or a switch the RM emulation does not forward), so after eight registrations svc.vas[] had no free slot: gsp_sema_service_vaspace_add silently refused the new directory (the 'if (vs)' guard), svc_walk_vaspaces kept walking only the dead clients' directories, and every walk of the new client's VAs failed -> its CE copies returned rc=-2 forever ('sema-optrace ... rc=-2' x8151 in the r466 log; the 10th+ client of the boot: streams2 bad=32737, streams_events no output, smiley hung, and the same class on r463/r465). This is the 'no launch stalls / no mid-boot degradation' blocker. Fix: - svc_vaspace_add evicts the least-recently-registered entry when the table is full instead of refusing (logged), and stamps every registration; - svc_walk_vaspaces orders the snapshot by registration stamp, newest first, so a live client's directory is the authority and a stale one (whose guest memory the driver has since reused) can only answer when the live directory cannot.
* r458 THE memset2d root cause: the CE copy decode read only LINE_LENGTH_IN ↵Arthur Hanson Rasmusson16 hours
| | | | | | | | | | | | | | | | | | | | | | | | | | and ignored the LINE_COUNT value the driver encodes in the SAME count=2 method group at 0x418 Raw push evidence (sema-op2d-raw, new bounded diagnostic): raw 17000520 7c7f0204 ... 20018104 00001000 20018105 00001000 20028106 00001000 00000100 20048100 7d7e 40c00000 The group at 0x418 carries count=2: v0 = LINE_LENGTH_IN (4096), v1 = LINE_COUNT (0x100 = 256 rows). The CE decode stored only v0, so st.line_count stayed 0, the 2D-copy builder took the single-row path (m->bytes = 4096) and a 4 MB cudaMemcpy2D delivered exactly ONE page per 1 MB block. memset2d_probe (new per-phase client) shows the exact shape: per-MB ok=4096 / bad=1044480 in all three phases, total 12,505,200 of 12,582,912 - deterministic across boots (r453/r454/r459 identical). The GRCE variant has always decoded the count=2 form (gr_line_count = v1); the CE path did not. Fix: CE_M_LINE_LENGTH_IN stores v1 into st.line_count when count >= 2, so the existing r420c contiguous-run logic (pitch == line => flat run of rows*line) finally sees the row count. The same decode feeds the fill path (cudaMemset2D). Also adds the bounded sema-op2d-raw witness (raw method stream of every pitch-shaped copy push) that produced the evidence, and a per-phase memset2d_probe client under tools/cuda-ab/.
* r457 free the copy staging snapshot only on consumption/slot-reuse/skip/TTL ↵Arthur Hanson Rasmusson18 hours
| | | | | | | | | | | | | | | | | | | | | | | | | | | (not on opdef_clear) The r456 change kept the snapshot alive across opdef APPLY, but the r457 mode-C run proved a second freer: svc_opdef_clear's FINISH path (entry consume via svc_replay_note) freed the b1 H2D's snapshot while the copy was still owed. The pin-batch rewind then REPLAYED the entry, the re-capture read the driver's REFILLED staging and the deferred execution wrote b2's bytes into db1. Evidence (r457, mode C, owner 0x5c00005c/1/0627e693d05aab3f): 191607.816388 copy snapshot captured dst=0x72e318c20000 src=0x72e31c400000 first4=00000000 3e800000 3f000000 3f400000 (b1) 191608.798838 copy snapshot captured <same key> first4=00000000 3d800000 3e000000 3e400000 (b2 - refilled staging) 191611.404931 sema-bigcopy dst_va=0x72e318c20000 src_va=0x72e31c400000 dst16_after=000000000000803d0000003e0000403e (b2 landed in db1) The op never succeeded (rc=-2 every pass), so the only free that could have dropped the first snapshot is the opdef_clear owner free. New lifecycle: capture once -> free on the copy's own successful consumption -> free on ring-slot reuse with a new push hash -> free when a re-decode skips an already-done op -> 30 s TTL. svc_copy_snap_free_owner keeps its rationale but is no longer called (the r444 cross-entry poisoning stays closed by the owner key + eviction).
* r456 keep the copy staging snapshot alive across opdef retries (the r455 ↵Arthur Hanson Rasmusson18 hours
| | | | | | | | | | | | | | | | | | | | | | | | | | operand-shift root cause) The fail4 pipeline-order snapshot (captured when a device-dst H2D copy is held for its operand pins) was freed by svc_opdef_clear on the APPLY path on every re-decode pass of the held entry. The retried copy therefore re-captured from the driver's REFILLED ping-pong staging: the a1 H2D of the r455 streams2_probe D run executed ~3 s after its push carrying a2's bytes (snapshot first4 flipped 00000000 3f000000.. -> 00000000 3e000000.. across retries; sema-bigcopy dst16_after=000000000000003e0000803e0000c03e proves the a2 pattern landed in da1's page; the vadd computed a2+b1 and the readback faithfully delivered it - there is no separate read-side landing bug for this class). - svc_opdef_clear: keep the snapshot on the APPLY path (the pass's own op execution, which consumes the snapshot on success, follows the apply); every genuine consume path (FINISH/FLUSH/DROP/STALE/COUNTED/ SWEEP/STOP) and the TTL still free it. - svc_copy_snap_capture: evict same-ring-slot snapshots with a different push hash (slot reuse) so the surviving snapshot can never serve a fresh push. - svc_run_ops: an op skipped via ops_done drops any snapshot a later re-decode re-captured for it (the leak the r444 APPLY-free used to sweep).
* r444 copy-snapshot ownership: key the fail4 held-copy staging snapshot by ↵Arthur Hanson Rasmusson25 hours
| | | | | | | | | | | | | | | | | | | | | (channel, ring entry, push-content hash), not (dst,src,total) alone The wedge_ab deterministic reproducer (bad = mutated-element count) root cause: a held CE copy's source snapshot was captured for one ring entry, left behind when that entry's copy executed through a path that never consumed it (hardware-primary forwarded copy, or a post-execution re-decode whose copy was re-held), and then consumed by a LATER entry's copy that happens to share the (dst,src,total) triple - the client's cudaMemcpy released early with the PREVIOUS step's bytes in the device buffer, and the next GR launch computed on stale inputs (r441/r442/r443 evidence: step N read step N-1 content; sema-bigcopy src16 shows the fresh live source at execution time while dst16_after shows the old snapshot's bytes). Owner identity is (ch->h_object, entry_idx, svc_pass_hash); the pass hash separates a ring slot reused by a fresh push from the entry that captured the snapshot. svc_opdef_clear() additionally frees any snapshot still owned by a consumed entry, so no snapshot can outlive its entry.
* sema: r420d bounded 2D-copy geometry witness (sema-op2d)Arthur Hanson Rasmusson33 hours
| | | | | | | Every copy op logs dst/src/bytes/rows/dpitch/spitch beside the decoded line_length/line_count/pitches, so the memset2d readback forensics can tell 'one row per push' from 'N rows in one op' and whether the pitch methods arrived. Bounded by the existing opadd budget.
* sema: r420c 2D fills/copies with pitch == row length cover all rowsArthur Hanson Rasmusson34 hours
| | | | | | | | | | | | | | | | | | victory_memset2d failed deterministically (bad ~= 12.5M of 12.58M) because its pitched operations carry PITCH == LINE_LENGTH (cudaMallocPitch returned pitch 4096 for width 4096) and the r402 2D decode only entered row mode when a pitch was WIDER than the row. The flat path then ran ONE row (LINE_LENGTH bytes) per op, so every cudaMemcpy2D readback and H2D upload delivered only its first row and every cudaMemset2D-sized region beyond it kept stale content - the 'deterministic readback loss' (45K of 12.58M correct ~= the rows the single runs happened to cover). LINE_COUNT is now authoritative for the flat case too: pitch == row length (or no pitch method) means CONTIGUOUS rows, so the single run covers rows*line bytes (element-exact when the line divides evenly, else byte exact). A pitch wider than the row keeps the r402 row-wise mode; 1D ops are unchanged. Both the fill (cudaMemset2D/fill) and the copy (cudaMemcpy2D) decode are fixed.
* gr: r420b author the guest QMD release on every outcome when release0 is ↵Arthur Hanson Rasmusson34 hours
| | | | | | | | | | | | | | | | | | | redirected With gsp_phys_rmcall_gr_rel_mod=1 (release0 -> module semaphore, the ordering fix for the engine-release-before-copy-out race) the engine never writes the guest's own QMD release word, so the host must author it on EVERY backend outcome. The hold's success/fail edges do; a launch with no deferred release records (no hold engaged) fell through and its client hung on a word nothing would ever write - the r414 saxpy f0 cur=5 stall. The backend now reports qmd_rel_redirected in the copy result whenever it points release0 at the module semaphore (rel_mod, or no targetable guest release page). svc_fwd_gr_work folds that into the existing gr_rel_unobserved latch, which makes the bounded outcome check author the word on done (success or failure) - the same forward-only write the hold edges perform. rel_mod=0 paths are unchanged (the engine still authors the word and the latch is only set on an unresolved release page).
* gr/sema: r420 pause completion deadlines under the backend wedge-quiet holdArthur Hanson Rasmusson34 hours
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The r419 soak reproduced the user's mid-boot degradation with the wedge fix in tree: victory_matmul printed bad=65536 while its launch was held by the booter's WEDGE-QUIET window - the client was released ~115 s before the post-hold accept. Root cause: two sema-service deadlines are shorter than the deliberate quiet hold and fire under it, authoring the launch's completion release (and applying its recorded releases) while the engine has not run and the copy-out has not happened: - the 12 s GR release hold (SVC_FWD_GR_HOLD_TIMEOUT_MS) expiry (GR-STALL-fwd-hold ... releases + QMD word software-applied), and - the 3 s per-launch consumption bound (gsp_phys_gr_hold_max_ms) firing the busy-defer consume-with-software-release path, whose inline apply authors the capture's QMD release (GR-REL-AUTHOR src=hold). Evidence (r419 live): push be94 captured 131333.687, WEDGE-QUIET holds 40 s + 80 s until 131345.598, accept 131346.552 - while the sema hold expired at 131230.978 (GR-STALL-fwd-hold waited_ms=12032) and the inline apply authored va=0x204027f7c pay=6 at 131341.734 (h=0x5c00001f). The client's verify completed on the authored word and read stale data. Fix: the booter publishes gsp_phys_gr_quiet_hold_active() exactly around the quiet msleep (bounded by construction). The sema service pauses under it: svc_fwd_hold_expired() pushes the GR deadline (bounded by a 600 s defence-in-depth cap, announced once per hold as GR-HOLD-PAUSE); svc_gr_hold_bound_expired() pushes the per-launch bound (GR-HOLD-BOUND-PAUSE); and the busy-defer one-shot window re-holds while the flag is set so the consume-with-sw-release path cannot run during a quiet hold. The held launch is then forwarded and copied out after the hold, and its completion is authored only on the hold's done edge - after the data write-back.
* sema: r408 acquire-wait gate defaults ON (the r408 streams2d readback race) ↵Arthur Hanson Rasmusson41 hours
| | | | | | | | | | | | | | + explicit param desc With the gate off (the mission cycle recipe omitted sema_wait_gate=1), the c2 readback's C56F ACQ_CIRC_GEQ pay=4 ran at 106617.279 with cur=2 - before the c2-add launch was even submitted (106617.411) - and read the not-yet-produced buffer (all zeros). With the gate on the same readback holds until the scale channel's progress counter reaches 4 (sema-wait: hold ... cur=2 waited_ms=353 -> pass ... cur=4) and the ordering is correct. The holds are bounded (sema_wait_hold_ms, default 4000) and fail open loudly, so the pre-r336 pass-through remains available with sema_wait_gate=0 for an A/B.
* sema: r407 drop-stale must not deliver a held entry's releases on a rewind ↵Arthur Hanson Rasmusson42 hours
| | | | | | | | | | | | | | | | | | | (only consumed entries are stale) The r406 inplace_scale repro root cause: the H2D copy's operand translation was unresolved (memcopy rc=-2) and the entry was held with its release withheld (correct); a pin-batch rewind then re-opened lower indices (83) while the held entry (91) sat ahead, and the unconditional svc_opdef_drop_stale treated 91 as an already-consumed entry and applied its withheld release at 104955.751. The copy itself only executed at 104957.418 - the client raced past its blocking cudaMemcpy, launched, the launch's copy-in read the stale buffer (previous run's data) and the copy landed after the launch's copy-out: wrong results with a healthy-looking 32/1032 changed and no classifier firing. An entry is only 'passed' if the ring consumed it (slot_done_epoch); gate the stale drop on svc_replay_seen so a rewind can never deliver a still-held entry's release early.
* sema: r402 pitched (2D) fills/copies + copy-dst divergence witnessArthur Hanson Rasmusson45 hours
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Two additions for the memset2d/memcpy_roundtrip and readback classes: 1. Pitched transfers. The CE decoder now captures LINE_COUNT (0x41c), PITCH_IN (0x410) and PITCH_OUT (0x414); a fill/copy whose LINE_COUNT is > 1 and whose destination pitch exceeds the row length builds a row-wise op (svc_fill/svc_copy are thin wrappers around the existing 1D bodies, advancing dst by dpitch and src by spitch per row). Each row keeps the whole per-page resolution/ledger/guard machinery, and a failed row's retry re-runs already-written rows with the same pattern (idempotent). A flat transfer carries pitch == row length (or no pitch method) and keeps the historical single-run path unchanged. Bounded 'sema-2d' row names every 2D op build. Note: the current victory_memset2d traffic reaches the engine as GR kernels plus per-row 4 KB CE copies, so this capability does not yet trigger for that client - it is the correct decoder for the CE-class 2D shape (driver channel_utils.c memset2d emits LINE_COUNT/PITCH). 2. DST-DIVERGE witness: when a copy destination resolves from the write ledger, a read-only resolver probe cross-checks the answer and logs (bounded, gsp_sema_dbg) when the writer's page differs from the live resolver's - the 'writer follows the ledger while the reader holds another page' shape behind the failed D2H staging class (streams2 c1 zeros, smiley pass failures). Zero rows fired on r403, so the ledger is not the active divergence for that boot; the witness stays for the next failing capture.
* sema: r401 acquire-wait hold bound + session-wide exactly-once capture memoryArthur Hanson Rasmusson46 hours
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Two fixes for the streams2 / multi-stream ordering class, both verified on fresh boot r401 with the acquire gate enabled: 1. sema_wait_hold_ms (new module param, default 4000 ms) replaces the hardcoded 100 ms acquire-wait bound in svc_run_ops. The old bound is shorter than one emulated GR launch completion (0.5-1.6 s observed), so a D2H readback's ACQ_CIRC_GEQ on the producer channel's progress counter (op=3 pay=4 on 0x20400ffd0) gave up and ran BEFORE the scale launch wrote d_c2; the client then verified pre-scale data (bad=32767). r401 log: the same entry now holds ~1.2 s across cur=1->4 and runs after GUEST GR LAUNCH OK (copy-back optrace 92315.594824 with dst16_after = the post-scale bytes). Fail-open is preserved: a genuinely unsatisfiable acquire still expires, just late enough that the dependency's work has landed (late-but-correct over early-and-wrong). 2. svc_gr_seen: a session-scoped open-addressed (push_va, hash) table behind svc_gr_cand_push_seen(). The 4-slot candidate ring + 8-VA history evicted a real capture within ~12 later captures, so a true replay of an already-forwarded launch was re-captured and re-executed (r399: the same nine launch pushes re-submitted every ~10-11 s for minutes). Cleared in svc_session_flush because a new client's identical-content pushes restart their release counters - a boot-scoped table would silently drop them (LAUNCH-SKIP). Also adds tools/cuda-ab/streams2d.cu: streams2 with per-array/per-4KB-block diff reporting plus the device pointer dump, which localised the remaining failure to the D2H staging write path (our staging-page resolution vs the guest's view).
* sema: r398 size the inline-once table to 8192 slots (256 KB)Arthur Hanson Rasmusson47 hours
| | | | | | | | r398 evidence: the memset's inline write executed twice for the same push (85634.101649 first, 85642.940808 replay 70 us before the D2H readback, zeroing the accumulator). 76 inline writes happened between the two - the 64-slot table had evicted the key. 8192 slots give a ~100x margin over the busiest observed burst.
* sema: r391f take 2 - once-only GRCE inline writes keyed by (push_va, push ↵Arthur Hanson Rasmusson48 hours
| | | | | | | | | | | | | | | | hash, dst, bytes) The first take gated on !replay, which broke pushes whose first pass was untrusted (their bytes are only authored on the later trusted pass) and hung the second client of the boot. Key the inline write by (push_va, push content hash, dst, bytes): a replay of the same push is a genuine duplicate and is skipped, a new push (its release payload makes the hash unique) always runs. Table is session-scoped (cleared by svc_session_flush), 64 slots. Root cause retained: victory_reduce's cudaMemset(d_sum,0,8) is a GRCE LOAD_INLINE_DATA write; every re-decode of that push re-ran it and re-zeroed the accumulator after the launch's copy-out (the sum=0 class).
* sema: r391f once-only GRCE inline writes - the sum=0 class root causeArthur Hanson Rasmusson48 hours
| | | | | | | | | | | | | | | | | | A REPLAYED ring entry must not re-run its LOAD_INLINE_DATA writes. The fill/copy ops were already gated by allow_ops (cleared for entry_replay), but the inline-write gate was 'trusted || allow_ops' and a replay is trusted by construction, so every re-decode of an already-processed push re-wrote its inline bytes into the vidmem shadow. victory_reduce's cudaMemset(d_sum, 0, 8) is exactly such an inline write. Observed on r396: 'sema-grce: inline write dst=0x7845ef000000 -> pa=0x7c00000 ap=vidmem bytes=8 data8=0000000000000000' fired 86 us before the D2H readback of the same VA - zeroing the accumulator the launch had just written (OUT-PAGE-POST val8=0000008000080000 = the correct sum) so the client read zeros (sum=0, bad=1). The same replay rewrote the page repeatedly (482 inline writes/boot). The r383 replay-capture path only needs to CAPTURE the launch; the inline bytes were authored on the first (non-replay) pass.
* sema/boot: r391e print the shadow base pointer in the copy-out and bigcopy ↵Arthur Hanson Rasmusson2 days
| | | | | | | | | | witnesses Rule in/out a stale or duplicate vgpu->bars[1] shadow between the launch copy-out (svc_fwd_req.vgpu) and the D2H reader (svc_copy's vgpu): the sum=0 runs show the write landing (OUT-PAGE-POST val8 = the sum) and the reader of the same ledger page reading zeros 8 ms later with no logged writer in between. Diagnostic only.
* sema/boot: r391c OUT-PAGE-WIT resolution witness for the sum=0 readback classArthur Hanson Rasmusson2 days
| | | | | | | | | | The GR copy-out now prints, per changed page, the landing-table resolution of the VA (the exact source the D2H reader's ledger-first branch uses) and its first 8 bytes beside the write target hpa - a launch/readback disagreement (write landed on another page/aperture than the reader resolves) becomes one line instead of a forensics session. Diagnostic only (bounded by the existing copywit budget).
* sema: r391b fix svc_op_translate polarity in the per-page fill resolverArthur Hanson Rasmusson2 days
| | | | | | | | | svc_op_translate returns 0 on success; the new svc_fill_dst_page_pa tested it without negation, so every page answerable only by the walk/scan returned -ENOENT and the fill truncated (r391 boot: FILL-TRUNC for the page-table writes at va=0x...a00200 -> the client stalled at init). Also demand the unresolved page through the pin channel before failing (stalled VA row -> the userspace stream pushes it to the guest scanner).
* sema: r391 per-page destination resolution for virtual fills - the r390 ↵Arthur Hanson Rasmusson2 days
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | guest panic root cause The 383620-byte context-init zero fill (FILL-NOREMAP class) resolved only its FIRST page through the pin (va=0x7c36c7400000 -> pa=0x131b63000, the pin stream's first run = 29 pages) and then wrote the whole 375 KiB contiguously past it. The pin stream shows the VA's pages are independent guest allocations with split runs (0x131b63000 / 0x131a80000 / 0x128340000), so the contiguous write covered unrelated memory - on r390 exactly the guest kernel's page-table pages 0x131ba1000/0x131ba2000/0x131bab000. The direct map grew three 4 KiB holes and the guest died with 'Fatal exception in interrupt' (unmap_page_range / cpuacct_account_field / psi_task_change faults on physmap addresses). svc_copy has always translated virtual operands per 4 KB page ('a linear PA walk past the first page reads the wrong memory'); svc_fill never did. New svc_fill_dst_page_pa() resolves every page of a virtual fill through the same authority order (fresh pin wins and repairs the landing table, then the landing table, then the resolver chain); the SYS write loop clamps each chunk to the page boundary and writes at that page's own landing; a page with no resolution fails the fill loudly (FILL-TRUNC) instead of writing through a contiguous guess. The >= 64 KiB landing-table pre-store now records only the contiguous VID (shadow) case; SYS landings are stored per page as they are written. Also extends the r384 page-table-shape refusal to every page of a virtual zero fill (the r390 fill's first page was the client's buffer, so the first-page-only check could not see the PTE pages it later covered). Evidence: /tmp/opencode/r390-live.log (FILL-EXEC + sema-opadd lines), /tmp/opencode/r390-guestram.raw (three zeroed PTE pages, CR3 walk), pin log 12-pin_gr_stream-r390.log line 789 (the split runs).
* sema: r384b narrow the fill pin-demand hold to SYS (guest RAM) resolutions + ↵Arthur Hanson Rasmusson2 days
| | | | | | | | | | | | | | | FILL-EXEC witness - The r384 boot held a large fill whose walk resolution was VID (the emulated vidmem shadow) - the hold was pointless overhead there and the re-decode re-resolves (the resolver is non-deterministic), so the hold now applies only when the fill would land in guest RAM (SYS aperture), the class that zeroed the guest's page-table pages. Shadow resolutions stay immediate. - FILL-EXEC witness (bounded 64/boot): va, pa, aperture, provenance and pattern of every >= 4 KiB virtual fill execution - the decisive line for the boot-corruption forensics; the large zero fills were invisible until now.
* sema: r384 fill-destination guards - pin-demand hold for large unproven ↵Arthur Hanson Rasmusson2 days
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | fills + page-table-shape refusal for zero fills (the boot-corruption lottery root-caused to zero writes landing on guest page-table pages) Forensics from the r383 boot (guest panic at t=216 during victory_strided): the guest kernel's direct map had TWO 2 MiB holes (phys 0x105000000 and 0x131800000) because their PTE pages at gpa 0x12d3c2000/0x3000 - two adjacent 4 KiB page-table pages - were found all-zero. Kernel objects (the kprobe nodes UVM registers at module load) lived in those regions; the first access after the zeroing faulted (Oops #1 get_kprobe from uvm_init_entry), cascading to the t=230 panic. The zeroing is an 8 KiB all-zero write, the exact shape of the guest's window page-table clear (LINE_LENGTH=8192, value=0), and the emulation's virtual fill resolver is demonstrably non-deterministic: four executions of that same 8 KiB fill resolved to four different guest pages (0x126af8000, 0x12d8e4000, 0x12f20c000, 0x1187fb000 - every one refused by the below-floor guard). The below-floor guard covers window VAs only; a >= 1 TiB VA fill that resolves through the walk/scan had no guard at all. Two nets in svc_fill, both default-on (sema_fill_guard=1) and both fail-open/histed: - net 1: a >= 64 KiB virtual fill whose only authority is the walk/scan (no pin, no landing-table entry) is held through a bounded 800 ms window (sema_fill_guard_ms) while its VA is demanded through the pin channel (the userspace pin stream injects the guest-pagemap truth), so the retried decode resolves through a real pin. Mirrors the m169/r378 copy guards; releases with the historical behaviour after the bound. - net 2: a ZERO fill about to land in guest RAM on a page whose first 64 qwords are all present+NX+in-range PTEs is REFUSED loudly (FILL-PT-REFUSED) - a page table page is never a legitimate zero-fill destination. Pin-backed resolutions are exempt (guest pagemap truth). New witnesses: FILL-HOLD (held fills) and FILL-PT-REFUSED (refused page-table targets), both bounded.
* sema/boot: r383 kill the blanket bounce copy-out (alias+staleness write ↵Arthur Hanson Rasmusson2 days
| | | | | | | | | surface) + write guards; REPLAY-CAPTURE closes the silent launch-drop hole; CE operand misses feed the pin-demand channel - bounce copy-out now records staged_hpa[bi] per launch and skips: (a) recs whose hpa != staged slot content (alias/leftover), (b) pages the engine did not change (~955 of 968 per boot launch); the remaining changed pages re-validate via gsp_sema_gr_write_guard before the 4 KiB memcpy. Removes the blanket 968-page write-back that was the remaining boot-corruption lottery vector (guest slab freelist clobbered by a foreign page write). - new bounded WGUARD-SKIP guards: gr_write_guard (pin-first re-resolution) on copy-out, release-word zero/restore (rel_va plumbed through the submit), stale-recover-zero, counter release; svc_write_guard pin-agreement on 4/8-byte SYS/FB service writes; svc_copy SYS-dst hold on a fresh-pin contradiction. - svc_qmd_accum replay hole: a trusted replay of an unseen push now captures (REPLAY-CAPTURE) instead of silently dropping; known push -> LAUNCH-SKIP witness; capture history ring prevents double-capture. - svc_op_translate miss path emits the stalled-VA demand signal for CE operands.
* sema: r377 pin-demand for unresolved launch operand pages - every dropped ↵Arthur Hanson Rasmusson2 days
| | | | data-fill page is logged as a stalled VA (the userspace pin stream watches dmesg for that line and pushes the VA to the in-guest scanner's demand file), so the bounded launch hold can resume on real pins instead of waiting out its bound (the r345 wedge)
* sema: r376 pin-agreement on the copy ledger-first branches - a fresh ↵Arthur Hanson Rasmusson2 days
| | | | disagreeing pin beats a recorded landing on both dst (write) and src (read) at top level and per page, repairing the entry; closes the stale-entry write (guest-corruption) and read (wrong-result) classes
* sema: r375b drop the resolver-answer ledger store - a stale resolver page ↵Arthur Hanson Rasmusson2 days
| | | | recorded as the write authority poisons every later write of the VA (r375 boot slab GPF in kmem_cache_alloc at guest t=77s before any client); the table is fed by writes and fresh pins only
* sema: r375 read-after-write authority - the landing table wins for device-VA ↵Arthur Hanson Rasmusson2 days
| | | | copy sources (top-level and per page), and a resolver answer is recorded so launch/read paths converge; the engine output can no longer be read through a different page/aperture than it was written
* sema: two-path identity check for the FB shadow hpa (__va(hpa) vs base+pa) - ↵Arthur Hanson Rasmusson2 days
| | | | the sum=0 class shows the engine output written through one path and read through the other
* sema: page-note resolution diagnostic (va/pa/ap/branch) for the launch-page ↵Arthur Hanson Rasmusson2 days
| | | | vs readback disagreement (sum=0 class); budget 512
* sema: pin-wins wave - a fresh pin re-homes the landing table ↵Arthur Hanson Rasmusson2 days
| | | | | | | | | | | | | | | | (svc_handle_map_add) and wins over the ledger in svc_gr_page_note, svc_gr_data_fill and svc_fill; gate the displaced-pin fan-out on a current pin match Root cause class (sub-agent audit + r371 log forensics): the landing table (ledger) moved only on host writes, so a VA re-pinned to a NEW page (CUDA reuses VA ranges across processes) kept resolving to the OLD, freed page. Every later write through that entry landed on memory the guest kernel had since reused - the r371 mail client's guest oops (NULL page array in nv_free_system_pages, 8 zero bytes) is this class. Fixes: (1) svc_handle_ map_add repairs a disagreeing ledger entry from the fresh pin (PIN-REPAIR); (2) svc_gr_page_note and svc_gr_data_fill keep a live pin over the ledger (PIN-WINS); (3) svc_fill checks the pin before the ledger fallback; (4) the pool alt fan-out writes the displaced page only while the current pin still names it (alt_skip). New diag: pinrep= alt_skip=.
* sema: store the landing table for every launch page in svc_gr_page_note - ↵Arthur Hanson Rasmusson2 days
| | | | indirect/bank operands (the kernel output buffer) resolved there while the client D2H readback used an older ledger landing, read stale zeros and the kernel looked wrong (victory_reduce sum=0 with the correct sum proven in the bounce page)
* sema: refuse below-floor fills that resolve outside vidmem (LOWFILL-REFUSED) ↵Arthur Hanson Rasmusson2 days
| | | | - the 0x204020000 engine-window clear resolved to a different guest-RAM page on every execution and zeroed 8 KB of guest kernel memory (gmain NULL deref in __fdget, task_struct corruption)
* sema: opdef and GR hold bounds are never re-armed while active - the ↵Arthur Hanson Rasmusson2 days
| | | | arm-on-VA-change rule moved the deadline on every held entry (streams2 wedge: opdef=955/13/0, drain held climbing, expired 0); entries held while a bound is active ride it and flush together
* sema: TABLE-COPY witness - dump carried bytes of page-table page/entry ↵Arthur Hanson Rasmusson2 days
| | | | copies (bounded) so zero-walking tables trace to their building copy or prove the source was zero
* sema: CE fill byte-exact semantics per the driver's own memset push - ↵Arthur Hanson Rasmusson2 days
| | | | LINE_LENGTH_IN is the size in BYTES (count=line_length/elem; the old count=line_length wrote elem x too much), value from DST_X mapping (CONST_A/CONST_B), r367
* sema: keep count=1 remapconst parts as flags only (NOT have_remap) - r365 ↵Arthur Hanson Rasmusson2 days
| | | | proved below-floor window fills executing via unproven resolution zeroed guest RAM (slab GPF -> guest panic); add LOWFILL-WIT resolution witness for below-floor fills
* sema: decode count=1 SET_REMAP_CONST A/B/COMPONENTS (the CE page-table fill ↵Arthur Hanson Rasmusson2 days
| | | | constants) + opt-in vidmem-window fill execution (gsp_sema_winfill, off) + FILL-RAW raw-push diagnostic; remapconst log budget 256
* sema: opdef absolute per-launch hold bound (GRFIX lesson) + physical ↵Arthur Hanson Rasmusson2 days
| | | | | | | | | | | | | | | | guest-RAM fill branch + diagnostics The opdef hold used a slot-keyed deadline that a pin-batch rewind re-arms on every replay (observed opdef=3301/32/0 with the guest wedged); the bound is now keyed to the launch push VA and written back through the pump snapshot, like the GR hold bound (r213). The fill op builder also accepts physical SYS destinations below the VA floor (guest-RAM page-table clears; bounded by SEMA_PA_MAX). The vidmem-window zero-fill experiment (r362) was reverted: executing those fills with elem=1 wrote 4-byte partial zeros and broke results (no drops but sum=0); the window fills need their true element size and value semantics decoded first (see handoff).
* sema: revert the capture-site launch hold (opdef holds accumulated without ↵Arthur Hanson Rasmusson2 days
| | | | expiry and wedged client init; keep the content-hash witness and the bound-expiry retry-forward)
* gr/sema: content-hash witness for the once-only op gate (rewritten fills now ↵Arthur Hanson Rasmusson3 days
| | | | run - stale GPU page tables class); launch hold without capture trust + bound-expiry retry-forward (no silent launch drop); guarded zero-fill for client device VAs; walk/rehold diagnostics
* gr: record the launch's resolved operand pages in the ledger - fixes the D2H ↵Arthur Hanson Rasmusson3 days
| | | | readback reading a stale page (victory_reduce sum=0 class); add GMMU walk trace + fwd-hpa diagnostics
* gr: single scheduling edge (pcas default 0) - fixes double engine execution; ↵Arthur Hanson Rasmusson3 days
| | | | retire-wait tracked-total fix; sema acquire wait gate per-entry + C56F op semantics (opt-in); fill-shape decode diagnostic
* vgsp: C56F acquire wait gate as an opt-in experiment (default off)Arthur Hanson Rasmusson3 days
| | | | | | | | | | | | | | | | | | | | | | The streams2 readback-before-scale class is root-caused: core CUDA starts compute-channel pushes with a C56F SEM_EXECUTE acquire (ACQ_CIRC_GEQ on a tracking semaphore; e.g. the D2H readback push waits on 0x20400fef0 >= its sequence number) and the decoder ignored it, so the copy ran ahead of the scale launch it waits for. The gate implemented here (decode the acquire; svc_run_ops holds the push's work until the semaphore satisfies, with the driver's release(N)+acquire(N) same-push pattern treated as satisfied; op-pending bounded hold; kill switch at 2048 holds; diagnostics sema-wait held rows with a per-session budget) OVER-HOLDS on boots where a channel's first pushes wait on counter values only their own withheld release would install (wait counts reach thousands, the client stalls; r337/r338/r339). The tracking-semaphore value semantics (what the guest word should read vs the driver's sequence numbers) need a dedicated pass before this can be enabled. Default OFF so behaviour is the pre-r336 one; enable per-boot with sema_wait_gate=1 for the experiment. Everything else (pin-wins, vector_add, the battery) is unaffected.
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