From 034dd340b08be1f2f0477ad16131d609f9dbd53c Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 30 Aug 2026 09:22:00 -0700 Subject: Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing fixes from Steven Rostedt: - Fix error output of boot instance creation failure Currently if a boot instance creation fails, instead of printing out the name of the instance that failed, it prints "(null)". That is because it prints "cur_str" that had already been processed by strsep(). Print the saved name instead. While at it, print the error code of the failure. - Fix use-after-free for same named historgrams Histograms can be named so that they can be used in multiple events. But if the named histogram has a variable attached, the second event that uses the named histogram which duplicates it and needs to free the original after duplication leaves the old variable in place and still visible. If another histogram uses than variable, it will use the stale one which will try to reference the freed duplicate histogram and crash the kernel. Free the duplicate variables along with the duplicated histogram data. - Check return value of kthread_run() in event self test The events self tests uses a kthread for testing but does not check if it succeeded in creating a kthread. If the kthread creation were to fail, the code will still try to call kthread_stop() on the error returned. - Fix race between reading trace_pipe and updating subbuffer size If a user is reading the trace_pipe file at the same time they update the ring buffer sub-buffer size, can cause the trace_pipe read to read stale data. Add trace_access_lock() around updating the ring buffer sub-buffer size. - Fix eventfs_inode on failure path in creation of the events directory In the creation of the "events" directory, if after allocating the eventfs_inode a failure is detected, it calls cleanup_ei() which calls free_ei(). The free_ei() will test if eventfs_inode being freed has no children. It is a bug if it does. But on the failure case of the creation of the "events" directory, the children lists have not yet been initialized and the free will trigger a warning because list_empty() on an uninitialized list returns false. Move the initialization into init_ei() where it makes more sense and makes sure that a created eventfs_inode has its lists initialized upon creation. - Check return value of kthread_run() in ftrace direct sample code The sample code that shows how to use the ftrace direct calls does not test the return of kthread_run() to see if it succeeds. Return a failure if the kthread_run() doesn't succeed. - Clear user events state on fork in case of alloc failure On fork, the child gets a pointer to the parent's user events state. It makes a copy of it then updates the child's pointer to it. But if the allocation fails, the duplication function leaves the child with a pointer to its parent's descriptor. When the child cleans up its data, it will free the parent's descriptor while the parent is still using it. In the duplication function, set the child's user_event_mm to NULL before testing if the allocation succeeded, and when it exits it will not free the parent's descriptor. - Fix retry exhaustion in simple ring buffer reader swap simple_ring_buffer_swap_reader_page() starts with retry set to 8 and post-decrements it only after a failed link replacement. On the final attempt, a successful replacement leaves retry at zero, while a failed replacement leaves it at -1. But the check for success expects the retry value to be non-zero and exits with an error on zero. This is the opposite result. Fix it. - Fail nicely when the remote swap_reader_page() returns an error Currently, if the swap_reader_page() of a remote buffer fails, it triggers a WARN_ON_ONCE() and continues normally. Instead, have it exit with an error and a pr_warn() print instead of a full WARNING. * tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: ring-buffer: Stop remote reader update when page swap fails tracing: Fix retry exhaustion in simple ring buffer reader swap tracing/user_events: Clear copied tracing state before fork duplication samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify eventfs: Initialize ei->children and ei->list in init_ei() tracing: Fix use-after-free in trace_pipe read on sub-buffer order change tracing: Fix crash passing ERR_PTR to kthread_stop() tracing: Fix use-after-free with same-name named triggers tracing: Fix logged instance name on creation failure --- scripts/rustdoc_test_gen.rs | 291 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 291 insertions(+) create mode 100644 scripts/rustdoc_test_gen.rs (limited to 'scripts/rustdoc_test_gen.rs') diff --git a/scripts/rustdoc_test_gen.rs b/scripts/rustdoc_test_gen.rs new file mode 100644 index 000000000..d087c0d9f --- /dev/null +++ b/scripts/rustdoc_test_gen.rs @@ -0,0 +1,291 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Generates KUnit tests from saved `rustdoc`-generated tests. +//! +//! KUnit passes a context (`struct kunit *`) to each test, which should be forwarded to the other +//! KUnit functions and macros. +//! +//! However, we want to keep this as an implementation detail because: +//! +//! - Test code should not care about the implementation. +//! +//! - Documentation looks worse if it needs to carry extra details unrelated to the piece +//! being described. +//! +//! - Test code should be able to define functions and call them, without having to carry +//! the context. +//! +//! - Later on, we may want to be able to test non-kernel code (e.g. `core` or third-party +//! crates) which likely use the standard library `assert*!` macros. +//! +//! For this reason, instead of the passed context, `kunit_get_current_test()` is used instead +//! (i.e. `current->kunit_test`). +//! +//! Note that this means other threads/tasks potentially spawned by a given test, if failing, will +//! report the failure in the kernel log but will not fail the actual test. Saving the pointer in +//! e.g. a `static` per test does not fully solve the issue either, because currently KUnit does +//! not support assertions (only expectations) from other tasks. Thus leave that feature for +//! the future, which simplifies the code here too. We could also simply not allow `assert`s in +//! other tasks, but that seems overly constraining, and we do want to support them, eventually. + +use std::{ + fs, + fs::File, + io::{ + BufWriter, + Read, + Write, // + }, + path::{ + Path, + PathBuf, // + }, // +}; + +/// Find the real path to the original file based on the `file` portion of the test name. +/// +/// `rustdoc` generated `file`s look like `sync_locked_by_rs`. Underscores (except the last one) +/// may represent an actual underscore in a directory/file, or a path separator. Thus the actual +/// file might be `sync_locked_by.rs`, `sync/locked_by.rs`, `sync_locked/by.rs` or +/// `sync/locked/by.rs`. This function walks the file system to determine which is the real one. +/// +/// This does require that ambiguities do not exist, but that seems fair, especially since this is +/// all supposed to be temporary until `rustdoc` gives us proper metadata to build this. If such +/// ambiguities are detected, they are diagnosed and the script panics. +fn find_real_path<'a>(srctree: &Path, valid_paths: &'a mut Vec, file: &str) -> &'a str { + valid_paths.clear(); + + let potential_components: Vec<&str> = file.strip_suffix("_rs").unwrap().split('_').collect(); + + find_candidates(srctree, valid_paths, Path::new(""), &potential_components); + fn find_candidates( + srctree: &Path, + valid_paths: &mut Vec, + prefix: &Path, + potential_components: &[&str], + ) { + // The base case: check whether all the potential components left, joined by underscores, + // is a file. + let joined_potential_components = potential_components.join("_") + ".rs"; + if srctree + .join("rust/kernel") + .join(prefix) + .join(&joined_potential_components) + .is_file() + { + // Avoid `srctree` here in order to keep paths relative to it in the KTAP output. + valid_paths.push( + Path::new("rust/kernel") + .join(prefix) + .join(joined_potential_components), + ); + } + + // In addition, check whether each component prefix, joined by underscores, is a directory. + // If not, there is no need to check for combinations with that prefix. + for i in 1..potential_components.len() { + let (components_prefix, components_rest) = potential_components.split_at(i); + let prefix = prefix.join(components_prefix.join("_")); + if srctree.join("rust/kernel").join(&prefix).is_dir() { + find_candidates(srctree, valid_paths, &prefix, components_rest); + } + } + } + + match valid_paths.as_slice() { + [] => panic!( + "No path candidates found for `{file}`. This is likely a bug in the build system, or \ + some files went away while compiling." + ), + [valid_path] => valid_path.to_str().unwrap(), + valid_paths => { + use std::fmt::Write; + + let mut candidates = String::new(); + for path in valid_paths { + writeln!(&mut candidates, " {path:?}").unwrap(); + } + panic!( + "Several path candidates found for `{file}`, please resolve the ambiguity by \ + renaming a file or folder. Candidates:\n{candidates}", + ); + } + } +} + +fn main() { + let srctree = std::env::var("srctree").unwrap(); + let srctree = Path::new(&srctree); + + let mut paths = fs::read_dir("rust/test/doctests/kernel") + .unwrap() + .map(|entry| entry.unwrap().path()) + .collect::>(); + + // Sort paths. + paths.sort(); + + let mut rust_tests = String::new(); + let mut c_test_declarations = String::new(); + let mut c_test_cases = String::new(); + let mut body = String::new(); + let mut last_file = String::new(); + let mut number = 0; + let mut valid_paths: Vec = Vec::new(); + let mut real_path: &str = ""; + for path in paths { + // The `name` follows the `{file}_{line}_{number}` pattern (see description in + // `scripts/rustdoc_test_builder.rs`). Discard the `number`. + let name = path.file_name().unwrap().to_str().unwrap().to_string(); + + // Extract the `file` and the `line`, discarding the `number`. + let (file, line) = name.rsplit_once('_').unwrap().0.rsplit_once('_').unwrap(); + + // Generate an ID sequence ("test number") for each one in the file. + if file == last_file { + number += 1; + } else { + number = 0; + last_file = file.to_string(); + + // Figure out the real path, only once per file. + real_path = find_real_path(srctree, &mut valid_paths, file); + } + + // Generate a KUnit name (i.e. test name and C symbol) for this test. + // + // We avoid the line number, like `rustdoc` does, to make things slightly more stable for + // bisection purposes. However, to aid developers in mapping back what test failed, we will + // print a diagnostics line in the KTAP report. + let kunit_name = format!("rust_doctest_kernel_{file}_{number}"); + + // Read the test's text contents to dump it below. + body.clear(); + File::open(path).unwrap().read_to_string(&mut body).unwrap(); + + // Calculate how many lines before `main` function (including the `main` function line). + let body_offset = body + .lines() + .take_while(|line| !line.contains("fn main() {")) + .count() + + 1; + + use std::fmt::Write; + write!( + rust_tests, + r#"/// Generated `{name}` KUnit test case from a Rust documentation test. +#[no_mangle] +pub extern "C" fn {kunit_name}(__kunit_test: *mut ::kernel::bindings::kunit) {{ + /// Overrides the usual [`assert!`] macro with one that calls KUnit instead. + #[allow(unused)] + macro_rules! assert {{ + ($cond:expr $(,)?) => {{{{ + ::kernel::kunit_assert!( + "{kunit_name}", c"{real_path}", __DOCTEST_ANCHOR - {line}, $cond + ); + }}}} + }} + + /// Overrides the usual [`assert_eq!`] macro with one that calls KUnit instead. + #[allow(unused)] + macro_rules! assert_eq {{ + ($left:expr, $right:expr $(,)?) => {{{{ + ::kernel::kunit_assert_eq!( + "{kunit_name}", c"{real_path}", __DOCTEST_ANCHOR - {line}, $left, $right + ); + }}}} + }} + + // Many tests need the prelude, so provide it by default. + #[allow(unused)] + use ::kernel::prelude::*; + + // Unconditionally print the location of the original doctest (i.e. rather than the location in + // the generated file) so that developers can easily map the test back to the source code. + // + // This information is also printed when assertions fail, but this helps in the successful cases + // when the user is running KUnit manually, or when passing `--raw_output` to `kunit.py`. + // + // This follows the syntax for declaring test metadata in the proposed KTAP v2 spec, which may + // be used for the proposed KUnit test attributes API. Thus hopefully this will make migration + // easier later on. + ::kernel::kunit::info(fmt!(" # {kunit_name}.location: {real_path}:{line}\n")); + + /// The anchor where the test code body starts. + #[allow(unused)] + static __DOCTEST_ANCHOR: i32 = ::core::line!() as i32 + {body_offset} + 2; + {{ + #![allow(unreachable_pub, clippy::disallowed_names)] + {body} + main(); + }} +}} + +"# + ) + .unwrap(); + + write!(c_test_declarations, "void {kunit_name}(struct kunit *);\n").unwrap(); + write!(c_test_cases, " KUNIT_CASE({kunit_name}),\n").unwrap(); + } + + let rust_tests = rust_tests.trim(); + let c_test_declarations = c_test_declarations.trim(); + let c_test_cases = c_test_cases.trim(); + + write!( + BufWriter::new(File::create("rust/doctests_kernel_generated.rs").unwrap()), + r#"//! `kernel` crate documentation tests. + +const __LOG_PREFIX: &[u8] = b"rust_doctests_kernel\0"; + +/// Dummy module type for doctest context. +struct LocalModule; + +use kernel::{{ + str::CStr, + ModuleMetadata, + ThisModule, // +}}; +use core::ptr::null_mut; + +impl ModuleMetadata for LocalModule {{ + const NAME: &'static CStr = c"rust_doctests_kernel"; + const THIS_MODULE: ThisModule = {{ + // SAFETY: `try_module_get`/`module_put` handle null module pointers gracefully. + unsafe {{ ThisModule::from_ptr(null_mut()) }} + }}; +}} + +{rust_tests} +"# + ) + .unwrap(); + + write!( + BufWriter::new(File::create("rust/doctests_kernel_generated_kunit.c").unwrap()), + r#"/* + * `kernel` crate documentation tests. + */ + +#include + +{c_test_declarations} + +static struct kunit_case test_cases[] = {{ + {c_test_cases} + {{ }} +}}; + +static struct kunit_suite test_suite = {{ + .name = "rust_doctests_kernel", + .test_cases = test_cases, +}}; + +kunit_test_suite(test_suite); + +MODULE_LICENSE("GPL"); +"# + ) + .unwrap(); +} -- cgit v1.3.1