(Cc: Mark)
On Wed Aug 12, 2026 at 6:33 PM CEST, Miguel Ojeda wrote:
> On Tue, Aug 11, 2026 at 8:41 AM Alvin Sun <[email protected]> wrote:
>>
>> The series moves `THIS_MODULE` into the `ModuleMetadata` as a const, threads
>> it
>> through `#[vtable]` to set `fops.owner` in DRM/miscdevice, and updates
>> configfs
>> and rnull to use `this_module::<LocalModule>()`.
>
> Applied to `rust-next` -- thanks everyone!
This series has a semantic conflict with both the driver-core and the drm-rust
tree:
@Mark: When you merge driver-core-next after rust-next (which I think is the
case) then you need to include the diff in [1] into the merge.
In drm-rust-next the build fails with:
error[E0425]: cannot find type `LocalModule` in the crate root
--> rust/kernel/drm/gem/shmem.rs:628:5
|
628 | #[vtable]
| ^^^^^^^^^ not found in the crate root
|
= note: this error originates in the attribute macro `vtable` (in
Nightly builds, run with -Z macro-backtrace for more info)
which is because the kunit test in rust/kernel/drm/gem/shmem.rs uses the
#[vtable] macro.
This should be fixed up with a patch on top of this series in rust-next.
I came up with to potential solutions [2] and [3]. I think with the new build
system we want [3], but I'm not entirely sure this works correctly with the
current build system in all cases (at least it did survive my tests).
Alternatively, we could just open-code a dummy module as in [2] for now.
[1] driver-core-next merge fixup
diff --git a/rust/kernel/serdev.rs b/rust/kernel/serdev.rs
index a4927452016e..17ca504b7f8d 100644
--- a/rust/kernel/serdev.rs
+++ b/rust/kernel/serdev.rs
@@ -87,7 +87,7 @@ unsafe fn register(
}
// SAFETY: `sdrv` is guaranteed to be a valid `DriverType`.
- to_result(unsafe {
bindings::__serdev_device_driver_register(sdrv.get(), module.0) })
+ to_result(unsafe {
bindings::__serdev_device_driver_register(sdrv.get(), module.as_ptr()) })
}
unsafe fn unregister(sdrv: &Opaque<Self::DriverType>) {
[2] Open-coded dummy module
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index c04e6c5aa7e0..274924cfcc05 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -157,6 +157,15 @@
/// Prefix to appear before log messages printed from within the `kernel`
crate.
const __LOG_PREFIX: &[u8] = b"rust_kernel\0";
+/// Dummy module type for `#[vtable]` impl blocks within the kernel crate
(e.g. kunit tests).
+struct LocalModule;
+
+impl ModuleMetadata for LocalModule {
+ const NAME: &'static str::CStr = c"rust_kernel";
+ // SAFETY: `try_module_get`/`module_put` handle null module pointers
gracefully.
+ const THIS_MODULE: ThisModule = unsafe {
ThisModule::from_ptr(core::ptr::null_mut()) };
+}
+
#[cfg(not(testlib))]
#[panic_handler]
fn panic(info: &core::panic::PanicInfo<'_>) -> ! {
[3] Allow module!() for kernel crate
diff --git a/rust/Makefile b/rust/Makefile
index 48adcd9b7851..4f6bf1b4d194 100644
--- a/rust/Makefile
+++ b/rust/Makefile
@@ -279,6 +279,7 @@ rustdoc-pin_init: $(src)/pin-init/src/lib.rs
rustdoc-pin_init_internal \
+$(call if_changed,rustdoc)
rustdoc-kernel: private is-kernel-object := y
+rustdoc-kernel: private rustc_target_envs = RUST_MODFILE=kernel/lib.rs
rustdoc-kernel: private rustc_target_flags = --extern ffi --extern pin_init \
--extern build_error --extern macros \
--extern bindings --extern uapi \
@@ -351,6 +352,7 @@ rusttestlib-pin_init: $(src)/pin-init/src/lib.rs
rusttestlib-macros \
rusttestlib-pin_init_internal $(obj)/$(libpin_init_internal_name) FORCE
+$(call if_changed,rustc_test_library)
+rusttestlib-kernel: private rustc_target_envs = RUST_MODFILE=kernel/lib.rs
rusttestlib-kernel: private rustc_target_flags = --extern ffi \
--extern build_error --extern macros --extern pin_init \
--extern bindings --extern uapi \
@@ -386,6 +388,7 @@ quiet_cmd_rustdoc_test_kernel = RUSTDOC TK $<
rm -rf $(objtree)/$(obj)/test/doctests/kernel; \
mkdir -p $(objtree)/$(obj)/test/doctests/kernel; \
$(rustc_target_envs) \
+ RUST_MODFILE=kernel/lib.rs \
OBJTREE=$(abspath $(objtree)) \
$(RUSTDOC) --test $(filter-out --remap-path-scope=%,$(rust_flags)) \
-L$(objtree)/$(obj) --extern ffi --extern pin_init \
@@ -788,6 +791,7 @@ $(obj)/uapi.o: $(src)/uapi/lib.rs \
$(obj)/uapi/uapi_generated.rs FORCE
+$(call if_changed_rule,rustc_library)
+$(obj)/kernel.o: private rustc_target_envs = RUST_MODFILE=kernel/lib.rs
$(obj)/kernel.o: private rustc_target_flags = --extern ffi --extern pin_init \
--extern build_error --extern macros --extern bindings --extern uapi \
--extern zerocopy --extern zerocopy_derive
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index c04e6c5aa7e0..7df9159788ad 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -154,8 +154,21 @@
};
pub use uapi;
-/// Prefix to appear before log messages printed from within the `kernel`
crate.
-const __LOG_PREFIX: &[u8] = b"rust_kernel\0";
+struct KernelCrateModule;
+
+impl Module for KernelCrateModule {
+ fn init(_module: &'static ThisModule) -> error::Result<Self> {
+ Ok(Self)
+ }
+}
+
+macros::module! {
+ type: KernelCrateModule,
+ name: "rust_kernel",
+ authors: ["Rust for Linux Contributors"],
+ description: "The kernel crate",
+ license: "GPL",
+}
#[cfg(not(testlib))]
#[panic_handler]
