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The `uapi` crate has the same problem > but nothing from it is exported. > > In practice this goes unnoticed because the only functions in `uapi` > are the trivial `Default` implementations generated by `bindgen`, > which rustc inlines across crates. With CONFIG_RUST_DEBUG_ASSERTIONS=3Dy > however, the `Default` implementation for structs can grow past the > automatic cross-crate inlining threshold. The module then references the > copy in `uapi.o`, which is not exported, and the build fails: > > ERROR: modpost: drivers/gpu/nova-drm.ko: symbol '_RNvXsH_Csk9v2ZIpWbWt_= 4uapiNtB5_17drm_nova_info_gpuNtNtCsfr3MPOfBGpN_4core7default7Default7defaul= t' undefined! Hmm, uapi' ideally should just be type exports and produce no code. Default implementation should carry `#[inline]` annotation so they're only codegenned in actual user crate. Rust's `#[derive(Default)]` would alw= ays add that. Can you check if that's bindgen-produced manual Default impl that somehow misses the attribute? Best, Gary > > Fix this by exporting the `uapi` symbols in the same way as `bindings`. > > Fixes: 4e1746656839 ("rust: uapi: Add UAPI crate") > Signed-off-by: Alistair Popple > Assisted-by: LLM > --- > rust/Makefile | 7 ++++++- > rust/exports.c | 1 + > 2 files changed, 7 insertions(+), 1 deletion(-) > > diff --git a/rust/Makefile b/rust/Makefile > index da1a7409d984..083992a5c1c9 100644 > --- a/rust/Makefile > +++ b/rust/Makefile > @@ -27,6 +27,7 @@ always-$(CONFIG_RUST) +=3D exports_bindings_generated.h= exports_kernel_generated.h > =20 > always-$(CONFIG_RUST) +=3D uapi/uapi_generated.rs > obj-$(CONFIG_RUST) +=3D uapi.o > +always-$(CONFIG_RUST) +=3D exports_uapi_generated.h > =20 > ifdef CONFIG_RUST_BUILD_ASSERT_ALLOW > obj-$(CONFIG_RUST) +=3D build_error.o > @@ -575,7 +576,8 @@ $(obj)/exports_core_generated.h: $(obj)/core.o FORCE > # in the crate where they are defined. Other helpers, called from non-in= line > # functions, may not be exported, in principle. However, in general, the= Rust > # compiler does not guarantee codegen will be performed for a non-inline > -# function either. Therefore, we export all symbols from helpers and bin= dings. > +# function either. Therefore, we export all symbols from helpers, bindin= gs and > +# uapi. > # In the future, this may be revisited to reduce the number of exports a= fter > # the compiler is informed about the places codegen is required. > $(obj)/exports_helpers_generated.h: $(obj)/helpers/helpers.o FORCE > @@ -587,6 +589,9 @@ $(obj)/exports_bindings_generated.h: $(obj)/bindings.= o FORCE > $(obj)/exports_kernel_generated.h: $(obj)/kernel.o FORCE > $(call if_changed,exports) > =20 > +$(obj)/exports_uapi_generated.h: $(obj)/uapi.o FORCE > + $(call if_changed,exports) > + > quiet_cmd_rustc_procmacrolibrary =3D $(if $(skip_clippy),RUSTC,$(RUSTC_O= R_CLIPPY_QUIET)) PL $@ > cmd_rustc_procmacrolibrary =3D \ > $(rustc_target_envs) \ > diff --git a/rust/exports.c b/rust/exports.c > index 1b52460b0f4e..434f0b73151f 100644 > --- a/rust/exports.c > +++ b/rust/exports.c > @@ -17,6 +17,7 @@ > =20 > #include "exports_core_generated.h" > #include "exports_bindings_generated.h" > +#include "exports_uapi_generated.h" > #include "exports_kernel_generated.h" > =20 > #ifndef CONFIG_RUST_INLINE_HELPERS > > base-commit: b705c185105762676aa6ec16cf976101df87cc35