| Filename | Latest commit message | Latest commit date |
|---|---|---|
25530e7eed
Started as "fix the ASAN leak in schfs_objtest" and the test turned out to be
the messenger. The allocation map was taken through a palloc callback and there
was no way to return it: no schfs_space_release, and a comment in
schfs_space_init reading "caller frees what was taken" for an API the caller
did not have.
Three separate leaks from that one gap:
* The kernel leaked the entire map on every unmount -- up to 2 MB, at 8 KiB
per GiB of volume -- because kmount_unmount flushed, cleared `mounted` and
walked away. This is the one that matters; the others are test-only.
* schfs_space_init stranded a page on its own error path. npages was raised
only after *both* of a pair of allocations succeeded, so a failure on the
second left the first outside the count -- unreachable to any cleanup that
could later exist.
* schfs_objtest leaked 2121728 bytes in 518 allocations, which is what made
the whole SchFS suite exit non-zero regardless of its assertions.
The map now carries its own pfree rather than taking one at release time, so it
can only ever be freed by the allocator that filled it -- the kernel's pages
come from kalloc and a host tool's from calloc, and the two are not
interchangeable. schfs_vol_open and schfs_vol_format release any map the volume
is already holding before building another, which is what stops a re-open
leaking; struct schfs_vol must therefore be zeroed before first use, and the
header now says so.
The test's own leak was the last one found and the simplest: it does
memset(&VOL, 0, sizeof(VOL)) before reopening, which wiped the map's pointers
before vol_open could release them. Eight of those, each now releasing first.
schfs_objtest asserts the balance -- 520 pages taken, 520 given back -- because
a suite that leaks cannot detect a leak: the filesystem's own allocations would
arrive as noise inside the harness's. The next one fails the run instead.
make schfs-check now exits 0. The 31 UBSAN misalignment reports are still
there and are still a Gate 0 item.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VQ7Qx8E1q1M1bbCq8QLHS2
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| .. | ||
| 1.0.md | ||
| foundations.md | ||
| hybrid.md | ||
| init.md | ||
| README.md | ||
| roadmap.md | ||
| schapi.md | ||
| wayland.md | ||
What happens next
Everything in this directory is unbuilt. When a piece of it is finished it leaves — deleted from here, rewritten as a description in ../architecture/. See the rule.
Read 1.0.md first.
It draws a finish line and puts most of the work below on the far side of it. Anything not named there is not being worked on, and the documents in this directory describe more than 1.0 contains.
The three current decisions
Taken together, because they turn out to need the same foundation.
| wayland.md | The GUI stack becomes Wayland. SchWM and SchDE are deleted; Schcom survives and changes its wire format. |
| hybrid.md | The kernel becomes hybrid — drivers move out into userspace processes, starting with the GPU. |
| init.md | PID 1 stops being a process and becomes a role the kernel guarantees is filled. |
And the one they all wait on:
| foundations.md | Descriptor passing, shared memory, sockets in the filesystem. The critical path. |
And the one that says which parts of the above are actually being worked on:
| 1.0.md | The finish line. Four gates, and everything else explicitly deferred. |
Two longer-horizon documents sit behind these: schapi.md, the API layering and the compatibility promise, and roadmap.md, which holds everything still open that is not one of the three above.
The order
Set by 1.0.md, which is the authority. In short:
0. Fix what is already wrong — first
Not a document of its own; it is Gate 0 of 1.0.md, assembled from the What it does not do sections in ../architecture/.
Before any new capability, and the reason is the one that put
netdev_selftest() before the TCP/IP stack: a compositor built on a kernel with
an unexplained hang and a socket layer that reports success for things it did not
do will fail in ways indistinguishable from its own bugs.
1. foundations.md — the critical path
Both the Wayland work and the hybrid work stop here. Descriptor passing and shared memory are the substrate for handing a buffer to a compositor and for handing a device to a driver process. Doing it once for both is the entire reason these are one plan rather than three.
2. init.md — before the desktop, not after
A compositor being brought up for the first time crashes constantly, and something that restarts it and says why is worth far more during that work than at the end of it.
3. wayland.md — with the GPU driver still in the kernel
W1–W3 and a terminal. W4 and W5 are post-1.0.
4. hybrid.md — after 1.0
Deliberately last: designing a userspace driver interface with no driver consuming it produces an interface that is wrong in ways nobody can see. The compositor is the demanding consumer that makes the interface judgeable, so it has to exist first.
In one sentence
Fix what is broken, build the descriptor-passing and shared-memory substrate, make init survivable, put a terminal on the screen — and only then use the compositor as the pressure that shapes the userspace driver interface.
What this plan does not address
Stated here so it is not mistaken for covered:
- No IOMMU, so the hybrid work isolates against bugs and not against a hostile driver.
- No page cache, so
foundations.mddelivers amemfdand not a general answer to shared file mappings. The general answer is still owed. - No dynamic linking, so no Mesa, no accelerated clients, and no third party
shipping a
.sofor anything. - A new compatibility surface between PID 1 and PID 2, created by a plan whose own schapi.md §3 spends a section warning about those.
- The three open networking items —
getsockname, routing, and interrupt-driven receive — are untouched by any of this and still open. They are in roadmap.md.