- Add try_idle_context() to ContextSwitchPercpu (switch.rs)
Cross-CPU paths (steal_work, migrate_one_context) use try_idle_context()
instead of idle_context() to avoid panic when APs haven't called
context::init() yet. Returns Option<context::Arc> instead of panicking.
- Pin rust-toolchain.toml to nightly-2026-04-11
- Remove build artifacts (kernel, kernel.all, kernel.sym) from git tracking
- This fixes the boot panic that occurred during multi-CPU scheduling
Reverts the prior session's -Z json-target-spec addition
that was breaking the build on nightly-2025-10-03 (the
kernel's rust-toolchain.toml specified toolchain). The
flag did not exist in that nightly; only nightly-2026-04-11
has it. Since the prior toolchain can build custom .json
target specs without any cargo-level gating (just pass
-Zunstable-options through -- separator to rustc),
the cleanest fix is to use rustc's -- directly:
cd SOURCE && cargo rustc -Z build-std=core,alloc ...
--bin kernel --target FILE --release
-- -C link-arg=...
RUSTUP_TOOLCHAIN=nightly-2025-10-03 is explicit so the
Makefile build works regardless of which toolchain the
outer shell has.
Also: restore rust-toolchain.toml to nightly-2025-10-03
(the version pinned in this fork). The 2026-04-01 bump
was a workaround attempt that did not work.
And: add .cargo/config.toml with [unstable]
json-target-spec = true as the new standard way (cargo
PR #16557) of enabling custom .json target specs. This
is harmless on older toolchains that don't have the feature
(cargo ignores unknown config keys).
Discovered via research into the nightly-2026-04-11 vs
nightly-2025-10-03 divergence after the redbear-mini build
failed with 'unknown -Z flag specified: json-target-spec'.
cargo 1.98.0-dev (4d1f98451 2026-05-15) requires
-Zunstable-options to be passed to cargo itself (not just
rustc) to accept a custom target spec. Without it, the
kernel Makefile fails with:
error: error loading target specification: custom targets
are unstable and require `-Zunstable-options`
The Makefile already had -Z build-std, -Zbuild-std-features,
and -Z json-target-spec (which are passed to rustc), but the
top-level cargo invocation needed -Zunstable-options
to accept the target.
This is required by both nightly-2025-10-03 (the kernel fork
rust-toolchain) and nightly-2026-04-01 (the host default). On
the cookbook (redoxer-1.0 toolchain), the error is the same
because -Zunstable-options is a separate cargo-level flag
from the rustc-level -Z flags.
Discovered when attempting to build redbear-mini after the
0.2.5 fork was created from 0.2.4. The Makefile worked on
0.2.4 because the prior kernel cook used a cached build; the
0.2.5 build started fresh and hit the error.
vasilito
Red Bear OS