Merge tag 'linux-kselftest-kunit-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

Pull kunit updates from Shuah Khan:

 - add support for running Rust documentation tests as KUnit tests

 - make init, str, sync, types doctests compilable/testable

 - add support for attributes API which include speed, modules
   attributes, ability to filter and report attributes

 - add support for marking tests slow using attributes API

 - add attributes API documentation

 - fix a wild-memory-access bug in kunit_filter_suites() and a possible
   memory leak in kunit_filter_suites()

 - add support for counting number of test suites in a module, list
   action to kunit test modules, and test filtering on module tests

* tag 'linux-kselftest-kunit-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest: (25 commits)
  kunit: fix struct kunit_attr header
  kunit: replace KUNIT_TRIGGER_STATIC_STUB maro with KUNIT_STATIC_STUB_REDIRECT
  kunit: Allow kunit test modules to use test filtering
  kunit: Make 'list' action available to kunit test modules
  kunit: Report the count of test suites in a module
  kunit: fix uninitialized variables bug in attributes filtering
  kunit: fix possible memory leak in kunit_filter_suites()
  kunit: fix wild-memory-access bug in kunit_filter_suites()
  kunit: Add documentation of KUnit test attributes
  kunit: add tests for filtering attributes
  kunit: time: Mark test as slow using test attributes
  kunit: memcpy: Mark tests as slow using test attributes
  kunit: tool: Add command line interface to filter and report attributes
  kunit: Add ability to filter attributes
  kunit: Add module attribute
  kunit: Add speed attribute
  kunit: Add test attributes API structure
  MAINTAINERS: add Rust KUnit files to the KUnit entry
  rust: support running Rust documentation tests as KUnit ones
  rust: types: make doctests compilable/testable
  ...

8 files changed, 197 insertions, 15 deletions

diff --git a/rust/kernel/init.rs b/rust/kernel/init.rs
index b4332a4ec1f4..e05563aad2ed 100644
--- a/rust/kernel/init.rs
+++ b/rust/kernel/init.rs
@@ -120,14 +120,24 @@
 //!   `slot` gets called.
 //!
 //! ```rust
-//! use kernel::{prelude::*, init};
+//! # #![allow(unreachable_pub, clippy::disallowed_names)]
+//! use kernel::{prelude::*, init, types::Opaque};
 //! use core::{ptr::addr_of_mut, marker::PhantomPinned, pin::Pin};
 //! # mod bindings {
+//! #     #![allow(non_camel_case_types)]
 //! #     pub struct foo;
 //! #     pub unsafe fn init_foo(_ptr: *mut foo) {}
 //! #     pub unsafe fn destroy_foo(_ptr: *mut foo) {}
 //! #     pub unsafe fn enable_foo(_ptr: *mut foo, _flags: u32) -> i32 { 0 }
 //! # }
+//! # // `Error::from_errno` is `pub(crate)` in the `kernel` crate, thus provide a workaround.
+//! # trait FromErrno {
+//! #     fn from_errno(errno: core::ffi::c_int) -> Error {
+//! #         // Dummy error that can be constructed outside the `kernel` crate.
+//! #         Error::from(core::fmt::Error)
+//! #     }
+//! # }
+//! # impl FromErrno for Error {}
 //! /// # Invariants
 //! ///
 //! /// `foo` is always initialized
@@ -158,7 +168,7 @@
 //!                 if err != 0 {
 //!                     // Enabling has failed, first clean up the foo and then return the error.
 //!                     bindings::destroy_foo(Opaque::raw_get(foo));
-//!                     return Err(Error::from_kernel_errno(err));
+//!                     return Err(Error::from_errno(err));
 //!                 }
 //!
 //!                 // All fields of `RawFoo` have been initialized, since `_p` is a ZST.
@@ -226,8 +236,7 @@ pub mod macros;
 ///
 /// ```rust
 /// # #![allow(clippy::disallowed_names, clippy::new_ret_no_self)]
-/// # use kernel::{init, pin_init, stack_pin_init, init::*, sync::Mutex, new_mutex};
-/// # use macros::pin_data;
+/// # use kernel::{init, macros::pin_data, pin_init, stack_pin_init, init::*, sync::Mutex, new_mutex};
 /// # use core::pin::Pin;
 /// #[pin_data]
 /// struct Foo {
@@ -277,7 +286,7 @@ macro_rules! stack_pin_init {
 ///
 /// # Examples
 ///
-/// ```rust
+/// ```rust,ignore
 /// # #![allow(clippy::disallowed_names, clippy::new_ret_no_self)]
 /// # use kernel::{init, pin_init, stack_try_pin_init, init::*, sync::Mutex, new_mutex};
 /// # use macros::pin_data;
@@ -303,7 +312,7 @@ macro_rules! stack_pin_init {
 /// pr_info!("a: {}", &*foo.a.lock());
 /// ```
 ///
-/// ```rust
+/// ```rust,ignore
 /// # #![allow(clippy::disallowed_names, clippy::new_ret_no_self)]
 /// # use kernel::{init, pin_init, stack_try_pin_init, init::*, sync::Mutex, new_mutex};
 /// # use macros::pin_data;
@@ -513,8 +522,7 @@ macro_rules! stack_try_pin_init {
 /// For instance:
 ///
 /// ```rust
-/// # use kernel::pin_init;
-/// # use macros::pin_data;
+/// # use kernel::{macros::pin_data, pin_init};
 /// # use core::{ptr::addr_of_mut, marker::PhantomPinned};
 /// #[pin_data]
 /// struct Buf {
@@ -841,7 +849,7 @@ macro_rules! init {
 /// # Examples
 ///
 /// ```rust
-/// use kernel::{init::PinInit, error::Error, InPlaceInit};
+/// use kernel::{init::{PinInit, zeroed}, error::Error};
 /// struct BigBuf {
 ///     big: Box<[u8; 1024 * 1024 * 1024]>,
 ///     small: [u8; 1024 * 1024],
diff --git a/rust/kernel/kunit.rs b/rust/kernel/kunit.rs
new file mode 100644
index 000000000000..722655b2d62d
--- /dev/null
+++ b/rust/kernel/kunit.rs
@@ -0,0 +1,163 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! KUnit-based macros for Rust unit tests.
+//!
+//! C header: [`include/kunit/test.h`](../../../../../include/kunit/test.h)
+//!
+//! Reference: <https://docs.kernel.org/dev-tools/kunit/index.html>
+
+use core::{ffi::c_void, fmt};
+
+/// Prints a KUnit error-level message.
+///
+/// Public but hidden since it should only be used from KUnit generated code.
+#[doc(hidden)]
+pub fn err(args: fmt::Arguments<'_>) {
+    // SAFETY: The format string is null-terminated and the `%pA` specifier matches the argument we
+    // are passing.
+    #[cfg(CONFIG_PRINTK)]
+    unsafe {
+        bindings::_printk(
+            b"\x013%pA\0".as_ptr() as _,
+            &args as *const _ as *const c_void,
+        );
+    }
+}
+
+/// Prints a KUnit info-level message.
+///
+/// Public but hidden since it should only be used from KUnit generated code.
+#[doc(hidden)]
+pub fn info(args: fmt::Arguments<'_>) {
+    // SAFETY: The format string is null-terminated and the `%pA` specifier matches the argument we
+    // are passing.
+    #[cfg(CONFIG_PRINTK)]
+    unsafe {
+        bindings::_printk(
+            b"\x016%pA\0".as_ptr() as _,
+            &args as *const _ as *const c_void,
+        );
+    }
+}
+
+/// Asserts that a boolean expression is `true` at runtime.
+///
+/// Public but hidden since it should only be used from generated tests.
+///
+/// Unlike the one in `core`, this one does not panic; instead, it is mapped to the KUnit
+/// facilities. See [`assert!`] for more details.
+#[doc(hidden)]
+#[macro_export]
+macro_rules! kunit_assert {
+    ($name:literal, $file:literal, $diff:expr, $condition:expr $(,)?) => {
+        'out: {
+            // Do nothing if the condition is `true`.
+            if $condition {
+                break 'out;
+            }
+
+            static FILE: &'static $crate::str::CStr = $crate::c_str!($file);
+            static LINE: i32 = core::line!() as i32 - $diff;
+            static CONDITION: &'static $crate::str::CStr = $crate::c_str!(stringify!($condition));
+
+            // SAFETY: FFI call without safety requirements.
+            let kunit_test = unsafe { $crate::bindings::kunit_get_current_test() };
+            if kunit_test.is_null() {
+                // The assertion failed but this task is not running a KUnit test, so we cannot call
+                // KUnit, but at least print an error to the kernel log. This may happen if this
+                // macro is called from an spawned thread in a test (see
+                // `scripts/rustdoc_test_gen.rs`) or if some non-test code calls this macro by
+                // mistake (it is hidden to prevent that).
+                //
+                // This mimics KUnit's failed assertion format.
+                $crate::kunit::err(format_args!(
+                    "    # {}: ASSERTION FAILED at {FILE}:{LINE}\n",
+                    $name
+                ));
+                $crate::kunit::err(format_args!(
+                    "    Expected {CONDITION} to be true, but is false\n"
+                ));
+                $crate::kunit::err(format_args!(
+                    "    Failure not reported to KUnit since this is a non-KUnit task\n"
+                ));
+                break 'out;
+            }
+
+            #[repr(transparent)]
+            struct Location($crate::bindings::kunit_loc);
+
+            #[repr(transparent)]
+            struct UnaryAssert($crate::bindings::kunit_unary_assert);
+
+            // SAFETY: There is only a static instance and in that one the pointer field points to
+            // an immutable C string.
+            unsafe impl Sync for Location {}
+
+            // SAFETY: There is only a static instance and in that one the pointer field points to
+            // an immutable C string.
+            unsafe impl Sync for UnaryAssert {}
+
+            static LOCATION: Location = Location($crate::bindings::kunit_loc {
+                file: FILE.as_char_ptr(),
+                line: LINE,
+            });
+            static ASSERTION: UnaryAssert = UnaryAssert($crate::bindings::kunit_unary_assert {
+                assert: $crate::bindings::kunit_assert {},
+                condition: CONDITION.as_char_ptr(),
+                expected_true: true,
+            });
+
+            // SAFETY:
+            //   - FFI call.
+            //   - The `kunit_test` pointer is valid because we got it from
+            //     `kunit_get_current_test()` and it was not null. This means we are in a KUnit
+            //     test, and that the pointer can be passed to KUnit functions and assertions.
+            //   - The string pointers (`file` and `condition` above) point to null-terminated
+            //     strings since they are `CStr`s.
+            //   - The function pointer (`format`) points to the proper function.
+            //   - The pointers passed will remain valid since they point to `static`s.
+            //   - The format string is allowed to be null.
+            //   - There are, however, problems with this: first of all, this will end up stopping
+            //     the thread, without running destructors. While that is problematic in itself,
+            //     it is considered UB to have what is effectively a forced foreign unwind
+            //     with `extern "C"` ABI. One could observe the stack that is now gone from
+            //     another thread. We should avoid pinning stack variables to prevent library UB,
+            //     too. For the moment, given that test failures are reported immediately before the
+            //     next test runs, that test failures should be fixed and that KUnit is explicitly
+            //     documented as not suitable for production environments, we feel it is reasonable.
+            unsafe {
+                $crate::bindings::__kunit_do_failed_assertion(
+                    kunit_test,
+                    core::ptr::addr_of!(LOCATION.0),
+                    $crate::bindings::kunit_assert_type_KUNIT_ASSERTION,
+                    core::ptr::addr_of!(ASSERTION.0.assert),
+                    Some($crate::bindings::kunit_unary_assert_format),
+                    core::ptr::null(),
+                );
+            }
+
+            // SAFETY: FFI call; the `test` pointer is valid because this hidden macro should only
+            // be called by the generated documentation tests which forward the test pointer given
+            // by KUnit.
+            unsafe {
+                $crate::bindings::__kunit_abort(kunit_test);
+            }
+        }
+    };
+}
+
+/// Asserts that two expressions are equal to each other (using [`PartialEq`]).
+///
+/// Public but hidden since it should only be used from generated tests.
+///
+/// Unlike the one in `core`, this one does not panic; instead, it is mapped to the KUnit
+/// facilities. See [`assert!`] for more details.
+#[doc(hidden)]
+#[macro_export]
+macro_rules! kunit_assert_eq {
+    ($name:literal, $file:literal, $diff:expr, $left:expr, $right:expr $(,)?) => {{
+        // For the moment, we just forward to the expression assert because, for binary asserts,
+        // KUnit supports only a few types (e.g. integers).
+        $crate::kunit_assert!($name, $file, $diff, $left == $right);
+    }};
+}
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index 85b261209977..3642cadc34b1 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -34,6 +34,8 @@ mod build_assert;
 pub mod error;
 pub mod init;
 pub mod ioctl;
+#[cfg(CONFIG_KUNIT)]
+pub mod kunit;
 pub mod prelude;
 pub mod print;
 mod static_assert;
diff --git a/rust/kernel/str.rs b/rust/kernel/str.rs
index c9dd3bf59e34..c41607b2e4fe 100644
--- a/rust/kernel/str.rs
+++ b/rust/kernel/str.rs
@@ -213,6 +213,7 @@ impl fmt::Display for CStr {
     ///
     /// ```
     /// # use kernel::c_str;
+    /// # use kernel::fmt;
     /// # use kernel::str::CStr;
     /// # use kernel::str::CString;
     /// let penguin = c_str!("🐧");
@@ -241,6 +242,7 @@ impl fmt::Debug for CStr {
     ///
     /// ```
     /// # use kernel::c_str;
+    /// # use kernel::fmt;
     /// # use kernel::str::CStr;
     /// # use kernel::str::CString;
     /// let penguin = c_str!("🐧");
@@ -529,7 +531,7 @@ impl fmt::Write for Formatter {
 /// # Examples
 ///
 /// ```
-/// use kernel::str::CString;
+/// use kernel::{str::CString, fmt};
 ///
 /// let s = CString::try_from_fmt(fmt!("{}{}{}", "abc", 10, 20)).unwrap();
 /// assert_eq!(s.as_bytes_with_nul(), "abc1020\0".as_bytes());
diff --git a/rust/kernel/sync/arc.rs b/rust/kernel/sync/arc.rs
index 172f563976a9..3d496391a9bd 100644
--- a/rust/kernel/sync/arc.rs
+++ b/rust/kernel/sync/arc.rs
@@ -73,6 +73,7 @@ mod std_vendor;
 /// assert_eq!(cloned.b, 20);
 ///
 /// // The refcount drops to zero when `cloned` goes out of scope, and the memory is freed.
+/// # Ok::<(), Error>(())
 /// ```
 ///
 /// Using `Arc<T>` as the type of `self`:
@@ -98,6 +99,7 @@ mod std_vendor;
 /// let obj = Arc::try_new(Example { a: 10, b: 20 })?;
 /// obj.use_reference();
 /// obj.take_over();
+/// # Ok::<(), Error>(())
 /// ```
 ///
 /// Coercion from `Arc<Example>` to `Arc<dyn MyTrait>`:
@@ -121,6 +123,7 @@ mod std_vendor;
 ///
 /// // `coerced` has type `Arc<dyn MyTrait>`.
 /// let coerced: Arc<dyn MyTrait> = obj;
+/// # Ok::<(), Error>(())
 /// ```
 pub struct Arc<T: ?Sized> {
     ptr: NonNull<ArcInner<T>>,
@@ -336,7 +339,7 @@ impl<T: ?Sized> From<Pin<UniqueArc<T>>> for Arc<T> {
 /// # Example
 ///
 /// ```
-/// use crate::sync::{Arc, ArcBorrow};
+/// use kernel::sync::{Arc, ArcBorrow};
 ///
 /// struct Example;
 ///
@@ -349,12 +352,13 @@ impl<T: ?Sized> From<Pin<UniqueArc<T>>> for Arc<T> {
 ///
 /// // Assert that both `obj` and `cloned` point to the same underlying object.
 /// assert!(core::ptr::eq(&*obj, &*cloned));
+/// # Ok::<(), Error>(())
 /// ```
 ///
 /// Using `ArcBorrow<T>` as the type of `self`:
 ///
 /// ```
-/// use crate::sync::{Arc, ArcBorrow};
+/// use kernel::sync::{Arc, ArcBorrow};
 ///
 /// struct Example {
 ///     a: u32,
@@ -369,6 +373,7 @@ impl<T: ?Sized> From<Pin<UniqueArc<T>>> for Arc<T> {
 ///
 /// let obj = Arc::try_new(Example { a: 10, b: 20 })?;
 /// obj.as_arc_borrow().use_reference();
+/// # Ok::<(), Error>(())
 /// ```
 pub struct ArcBorrow<'a, T: ?Sized + 'a> {
     inner: NonNull<ArcInner<T>>,
diff --git a/rust/kernel/sync/lock/mutex.rs b/rust/kernel/sync/lock/mutex.rs
index 923472f04af4..09276fedc091 100644
--- a/rust/kernel/sync/lock/mutex.rs
+++ b/rust/kernel/sync/lock/mutex.rs
@@ -63,6 +63,7 @@ macro_rules! new_mutex {
 /// assert_eq!(e.c, 10);
 /// assert_eq!(e.d.lock().a, 20);
 /// assert_eq!(e.d.lock().b, 30);
+/// # Ok::<(), Error>(())
 /// ```
 ///
 /// The following example shows how to use interior mutability to modify the contents of a struct
diff --git a/rust/kernel/sync/lock/spinlock.rs b/rust/kernel/sync/lock/spinlock.rs
index 979b56464a4e..91eb2c9e9123 100644
--- a/rust/kernel/sync/lock/spinlock.rs
+++ b/rust/kernel/sync/lock/spinlock.rs
@@ -61,6 +61,7 @@ macro_rules! new_spinlock {
 /// assert_eq!(e.c, 10);
 /// assert_eq!(e.d.lock().a, 20);
 /// assert_eq!(e.d.lock().b, 30);
+/// # Ok::<(), Error>(())
 /// ```
 ///
 /// The following example shows how to use interior mutability to modify the contents of a struct
diff --git a/rust/kernel/types.rs b/rust/kernel/types.rs
index d479f8da8f38..e33b901ab0a4 100644
--- a/rust/kernel/types.rs
+++ b/rust/kernel/types.rs
@@ -91,7 +91,7 @@ impl ForeignOwnable for () {
 /// In the example below, we have multiple exit paths and we want to log regardless of which one is
 /// taken:
 /// ```
-/// # use kernel::ScopeGuard;
+/// # use kernel::types::ScopeGuard;
 /// fn example1(arg: bool) {
 ///     let _log = ScopeGuard::new(|| pr_info!("example1 completed\n"));
 ///
@@ -109,7 +109,7 @@ impl ForeignOwnable for () {
 /// In the example below, we want to log the same message on all early exits but a different one on
 /// the main exit path:
 /// ```
-/// # use kernel::ScopeGuard;
+/// # use kernel::types::ScopeGuard;
 /// fn example2(arg: bool) {
 ///     let log = ScopeGuard::new(|| pr_info!("example2 returned early\n"));
 ///
@@ -130,7 +130,7 @@ impl ForeignOwnable for () {
 /// In the example below, we need a mutable object (the vector) to be accessible within the log
 /// function, so we wrap it in the [`ScopeGuard`]:
 /// ```
-/// # use kernel::ScopeGuard;
+/// # use kernel::types::ScopeGuard;
 /// fn example3(arg: bool) -> Result {
 ///     let mut vec =
 ///         ScopeGuard::new_with_data(Vec::new(), |v| pr_info!("vec had {} elements\n", v.len()));