2 Commits

Author	SHA1	Message	Date
enricobuehler	f68f6bc590	fix(linux): zerocopy worker survives the host binary being replaced on disk ... A pacman canary upgrade under a running host (0.5284→0.5338, 09:24 today) unlinked /usr/bin/punktfunk-host; current_exe() then readlinked to "<path> (deleted)", every worker spawn failed ENOENT, and each session silently fell back to the CPU linear-copy capture — observed as the box "regressing" to ~90 fps at 5-7 MP until a service restart. - RemoteImporter::spawn now pins a read fd to /proc/self/exe (once, kept for the process lifetime) and execs the worker via /proc/self/fd/<n>. The magic link names the running image's inode, not its path, so the spawn survives replacement/deletion — and the worker is always byte-for-byte the host's own build, so a mid-upgrade spawn can't hit a worker-protocol skew either. If the fd draws number 3 (the worker's socket slot — the pre-exec dup2 would clobber it) it is re-numbered; if /proc is unavailable the old path-based spawn remains as fallback. - argv[0] is set to "punktfunk-host" and the worker prctl-renames its comm to "pf-zerocopy" — exec-by-fd-path would otherwise show a bare fd number in ps and top. - zerocopy-probe now also spawns the worker (handshake + modifier query), so the probe catches spawn-level breakage, not just FFI/GPU bring-up. Verified end-to-end on the dev box: probe with the binary unlinked mid-run (/proc/self/exe → "(deleted)") still spawns the worker and reports all 13 modifiers. New unit tests cover the pinned spawn and the deleted-file exec; the latter retries ETXTBSY (fs::copy's write fd leaks into other tests' forked children until their execs clear it — a copy-then-exec harness artifact, not a production concern). Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>	2026-07-10 11:34:13 +02:00
enricobuehler	1d17524151	feat(host): isolate the zero-copy GPU import in a worker process ... The tiled EGL/GL→CUDA import crashed the whole host (SIGSEGV inside libnvidia-eglcore via cuGraphicsMapResources) when the compositor invalidated an imported dmabuf mid-map — reproduced on the Bazzite F44 Game→Desktop switch (design/zerocopy-hardening-handoff.md). A driver SIGSEGV is uncatchable in-process, so the whole EglImporter (tiled EGL/GL→CUDA and LINEAR Vulkan→CUDA) now runs in a per-capture `zerocopy-worker` subprocess: dmabuf fds go over a SEQPACKET socketpair (SCM_RIGHTS, sent once per buffer keyed by dmabuf st_ino; NeedFd resend self-heals cache desync), frames come back as CUDA-IPC pooled device buffers (still zero-copy, +one socket RTT/frame). Worker death poisons the capturer so the existing capture-loss rebuild runs — the host survives; 3 consecutive deaths latch the GPU import off (CPU/SHM path). PUNKTFUNK_ZEROCOPY_INPROC=1 keeps the old in-process import for debugging/A-B. Also fixed along the way: a failed *tiled* import no longer falls through to the CPU mmap de-pad (which scrambled tiled bytes; LINEAR keeps the fallback); Nv12Blit dropped its GL textures while still CUDA-registered (unregister now runs first); GlBlit had no Drop at all (GL objects leaked per size change); VkBridge's per-fd src cache is now invalidated on renegotiation/eviction instead of never. Design: design/zerocopy-worker-isolation.md. Unit tests: 14 new (protocol fd-passing, worker dispatch, client handshake/death/NeedFd, death latch). On-glass validated on the RTX 5070 Ti/GNOME box (.21): the worker path streams at p50 1.30 ms (NV12, 1800 frames 0-mismatched, parity with the in-process path), and a kill -9 of the worker mid-stream is survived by the host and recovered — poison -> capture lost, rebuilding pipeline in place -> a fresh worker in ~185 ms -> streaming resumes (2385 frames, 0 mismatched). A real KWin compositor-crash repro is still pending (a worker kill -9 is strictly harsher, so it corroborates). Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>	2026-07-06 10:33:43 +00:00