On Thu Mar 13, 2025 at 11:47 AM CET, Tamir Duberstein wrote:
On Wed, Mar 12, 2025 at 6:38 PM Benno Lossin benno.lossin@proton.me wrote:
On Wed Mar 12, 2025 at 11:24 PM CET, Tamir Duberstein wrote:
On Wed, Mar 12, 2025 at 5:30 PM Benno Lossin benno.lossin@proton.me wrote:
On Wed Mar 12, 2025 at 10:10 PM CET, Tamir Duberstein wrote:
On Wed, Mar 12, 2025 at 5:04 PM Tamir Duberstein tamird@gmail.com wrote:
On Wed, Mar 12, 2025 at 5:01 PM Benno Lossin benno.lossin@proton.me wrote: > Always enable the features, we have `allow(stable_features)` for this > reason (then you don't have to do this dance with checking if it's > already stable or not :)
It's not so simple. In rustc < 1.84.0 the lints *and* the strict provenance APIs are behind `feature(strict_provenance)`. In rustc >= 1.84.0 the lints are behind `feature(strict_provenance_lints)`. So you need to read the config to learn that you need to enable `feature(strict_provenance_lints)`.
I see... And `strict_provenance_lints` doesn't exist in <1.84? That's a bit of a bummer...
But I guess we could have this config option (in `init/Kconfig`):
config RUSTC_HAS_STRICT_PROVENANCE def_bool RUSTC_VERSION >= 108400and then do this in `lib.rs`:
#![cfg_attr(CONFIG_RUSTC_HAS_STRICT_PROVENANCE, feature(strict_provenance_lints))]Yep! That's exactly what I did, but as I mentioned up-thread, the result is that we only cover the `kernel` crate.
Ah I see, can't we just have the above line in the other crate roots?
The most difficult case is doctests. You'd have to add this to every example AFAICT.
Actually this isn't even the only problem. It seems that `-Astable_features` doesn't affect features enabled on the command line at all:
error[E0725]: the feature `strict_provenance` is not in the list of allowed features --> <crate attribute>:1:9 | 1 | feature(strict_provenance) | ^^^^^^^^^^^^^^^^^
That's because you need to append the feature to `rust_allowed_features` in `scripts/Makefile.build` (AFAIK).
Thanks, that's a helpful pointer, and it solves some problems but not all. The root Makefile contains this bit:
KBUILD_HOSTRUSTFLAGS := $(rust_common_flags) -O -Cstrip=debuginfo \ -Zallow-features= $(HOSTRUSTFLAGS)
which means we can't use the provenance lints against these host targets (including e.g. `rustdoc_test_gen`). We can't remove this -Zallow-features= either because then core fails to compile.
I'm at the point where I think I need more involved help. Want to take a look at my attempt? It's here: https://github.com/tamird/linux/tree/b4/ptr-as-ptr.
With doing `allow(clippy::incompatible_msrv)`, I meant doing that globally, not having a module to re-export the functions :)
I'll take a look tomorrow, you're testing my knowledge of the build system a lot here :)
We're guaranteed to learn something :)
Yep! I managed to get it working, but it is rather janky and experimental. I don't think you should use this in your patch series unless Miguel has commented on it.
Notable things in the diff below: * the hostrustflags don't get the *provenance_casts lints (which is correct, I think, but probably not the way I did it with filter-out) * the crates compiler_builtins, bindings, uapi, build_error, libmacros, ffi, etc do get them, but probably shouldn't?
--- Cheers, Benno
diff --git a/Makefile b/Makefile index 70bdbf2218fc..38a79337cd7b 100644 --- a/Makefile +++ b/Makefile @@ -473,6 +473,8 @@ export rust_common_flags := --edition=2021 \ -Astable_features \ -Dnon_ascii_idents \ -Dunsafe_op_in_unsafe_fn \ + -Wfuzzy_provenance_casts \ + -Wlossy_provenance_casts \ -Wmissing_docs \ -Wrust_2018_idioms \ -Wunreachable_pub \ @@ -493,7 +495,7 @@ KBUILD_HOSTCFLAGS := $(KBUILD_USERHOSTCFLAGS) $(HOST_LFS_CFLAGS) \ $(HOSTCFLAGS) -I $(srctree)/scripts/include KBUILD_HOSTCXXFLAGS := -Wall -O2 $(HOST_LFS_CFLAGS) $(HOSTCXXFLAGS) \ -I $(srctree)/scripts/include -KBUILD_HOSTRUSTFLAGS := $(rust_common_flags) -O -Cstrip=debuginfo \ +KBUILD_HOSTRUSTFLAGS := $(filter-out -Wfuzzy_provenance_casts -Wlossy_provenance_casts,$(rust_common_flags)) -O -Cstrip=debuginfo \ -Zallow-features= $(HOSTRUSTFLAGS) KBUILD_HOSTLDFLAGS := $(HOST_LFS_LDFLAGS) $(HOSTLDFLAGS) KBUILD_HOSTLDLIBS := $(HOST_LFS_LIBS) $(HOSTLDLIBS) diff --git a/init/Kconfig b/init/Kconfig index d0d021b3fa3b..82e28d6f7c3f 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -132,6 +132,9 @@ config CC_HAS_COUNTED_BY config RUSTC_HAS_COERCE_POINTEE def_bool RUSTC_VERSION >= 108400
+config RUSTC_HAS_STABLE_STRICT_PROVENANCE + def_bool RUSTC_VERSION >= 108400 + config PAHOLE_VERSION int default $(shell,$(srctree)/scripts/pahole-version.sh $(PAHOLE)) diff --git a/rust/Makefile b/rust/Makefile index ea3849eb78f6..998b57c6e5f7 100644 --- a/rust/Makefile +++ b/rust/Makefile @@ -436,7 +436,8 @@ $(obj)/helpers/helpers.o: $(src)/helpers/helpers.c $(recordmcount_source) FORCE $(obj)/exports.o: private skip_gendwarfksyms = 1
$(obj)/core.o: private skip_clippy = 1 -$(obj)/core.o: private skip_flags = -Wunreachable_pub +$(obj)/core.o: private skip_flags = -Wunreachable_pub \ + -Wfuzzy_provenance_casts -Wlossy_provenance_casts $(obj)/core.o: private rustc_objcopy = $(foreach sym,$(redirect-intrinsics),--redefine-sym $(sym)=__rust$(sym)) $(obj)/core.o: private rustc_target_flags = $(core-cfgs) $(obj)/core.o: $(RUST_LIB_SRC)/core/src/lib.rs \ diff --git a/rust/bindings/lib.rs b/rust/bindings/lib.rs index 014af0d1fc70..185bf29e44d9 100644 --- a/rust/bindings/lib.rs +++ b/rust/bindings/lib.rs @@ -9,6 +9,14 @@ //! using this crate.
#![no_std] +#![cfg_attr( + not(CONFIG_RUSTC_HAS_STABLE_STRICT_PROVENANCE), + feature(strict_provenance) +)] +#![cfg_attr( + CONFIG_RUSTC_HAS_STABLE_STRICT_PROVENANCE, + feature(strict_provenance_lints) +)] // See https://github.com/rust-lang/rust-bindgen/issues/1651. #![cfg_attr(test, allow(deref_nullptr))] #![cfg_attr(test, allow(unaligned_references))] diff --git a/rust/build_error.rs b/rust/build_error.rs index fa24eeef9929..84e24598857f 100644 --- a/rust/build_error.rs +++ b/rust/build_error.rs @@ -18,6 +18,14 @@ //! [const-context]: https://doc.rust-lang.org/reference/const_eval.html#const-context
#![no_std] +#![cfg_attr( + not(CONFIG_RUSTC_HAS_STABLE_STRICT_PROVENANCE), + feature(strict_provenance) +)] +#![cfg_attr( + CONFIG_RUSTC_HAS_STABLE_STRICT_PROVENANCE, + feature(strict_provenance_lints) +)]
/// Panics if executed in [const context][const-context], or triggers a build error if not. /// diff --git a/rust/compiler_builtins.rs b/rust/compiler_builtins.rs index f14b8d7caf89..0dcb25a644f6 100644 --- a/rust/compiler_builtins.rs +++ b/rust/compiler_builtins.rs @@ -21,6 +21,14 @@
#![allow(internal_features)] #![feature(compiler_builtins)] +#![cfg_attr( + not(CONFIG_RUSTC_HAS_STABLE_STRICT_PROVENANCE), + feature(strict_provenance) +)] +#![cfg_attr( + CONFIG_RUSTC_HAS_STABLE_STRICT_PROVENANCE, + feature(strict_provenance_lints) +)] #![compiler_builtins] #![no_builtins] #![no_std] diff --git a/rust/ffi.rs b/rust/ffi.rs index 584f75b49862..28a5e9a09b70 100644 --- a/rust/ffi.rs +++ b/rust/ffi.rs @@ -8,6 +8,14 @@ //! C ABI. The kernel does not use [`core::ffi`], so it can customise the mapping that deviates from //! the platform default.
+#![cfg_attr( + not(CONFIG_RUSTC_HAS_STABLE_STRICT_PROVENANCE), + feature(strict_provenance) +)] +#![cfg_attr( + CONFIG_RUSTC_HAS_STABLE_STRICT_PROVENANCE, + feature(strict_provenance_lints) +)] #![no_std]
macro_rules! alias { diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index 398242f92a96..6fd4fb2176aa 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -13,6 +13,14 @@
#![no_std] #![feature(arbitrary_self_types)] +#![cfg_attr( + not(CONFIG_RUSTC_HAS_STABLE_STRICT_PROVENANCE), + feature(strict_provenance) +)] +#![cfg_attr( + CONFIG_RUSTC_HAS_STABLE_STRICT_PROVENANCE, + feature(strict_provenance_lints) +)] #![cfg_attr(CONFIG_RUSTC_HAS_COERCE_POINTEE, feature(derive_coerce_pointee))] #![cfg_attr(not(CONFIG_RUSTC_HAS_COERCE_POINTEE), feature(coerce_unsized))] #![cfg_attr(not(CONFIG_RUSTC_HAS_COERCE_POINTEE), feature(dispatch_from_dyn))] diff --git a/rust/macros/lib.rs b/rust/macros/lib.rs index 8c7b786377ee..91450de998d3 100644 --- a/rust/macros/lib.rs +++ b/rust/macros/lib.rs @@ -2,6 +2,15 @@
//! Crate for all kernel procedural macros.
+#![cfg_attr( + not(CONFIG_RUSTC_HAS_STABLE_STRICT_PROVENANCE), + feature(strict_provenance) +)] +#![cfg_attr( + CONFIG_RUSTC_HAS_STABLE_STRICT_PROVENANCE, + feature(strict_provenance_lints) +)] + // When fixdep scans this, it will find this string `CONFIG_RUSTC_VERSION_TEXT` // and thus add a dependency on `include/config/RUSTC_VERSION_TEXT`, which is // touched by Kconfig when the version string from the compiler changes. diff --git a/rust/uapi/lib.rs b/rust/uapi/lib.rs index 13495910271f..84ef3828e0d4 100644 --- a/rust/uapi/lib.rs +++ b/rust/uapi/lib.rs @@ -8,6 +8,14 @@ //! userspace APIs.
#![no_std] +#![cfg_attr( + not(CONFIG_RUSTC_HAS_STABLE_STRICT_PROVENANCE), + feature(strict_provenance) +)] +#![cfg_attr( + CONFIG_RUSTC_HAS_STABLE_STRICT_PROVENANCE, + feature(strict_provenance_lints) +)] // See https://github.com/rust-lang/rust-bindgen/issues/1651. #![cfg_attr(test, allow(deref_nullptr))] #![cfg_attr(test, allow(unaligned_references))] diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 993708d11874..021ee36ae8f2 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -226,7 +226,10 @@ $(obj)/%.lst: $(obj)/%.c FORCE # Compile Rust sources (.rs) # ---------------------------------------------------------------------------
-rust_allowed_features := asm_const,asm_goto,arbitrary_self_types,lint_reasons +# Lints were moved to `strict_provenance_lints` when `strict_provenance` was stabilized. +# +# See https://github.com/rust-lang/rust/commit/56ee492a6e7a917b2b3f888e33dd52a13d3.... +rust_allowed_features := asm_const,asm_goto,arbitrary_self_types,lint_reasons,$(if $(CONFIG_RUSTC_HAS_STABLE_STRICT_PROVENANCE),strict_provenance_lints,strict_provenance)
# `--out-dir` is required to avoid temporaries being created by `rustc` in the # current working directory, which may be not accessible in the out-of-tree