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 --- rust/syn/error.rs | 469 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 469 insertions(+) create mode 100644 rust/syn/error.rs (limited to 'rust/syn/error.rs') diff --git a/rust/syn/error.rs b/rust/syn/error.rs new file mode 100644 index 000000000..6fa0faf7f --- /dev/null +++ b/rust/syn/error.rs @@ -0,0 +1,469 @@ +// SPDX-License-Identifier: Apache-2.0 OR MIT + +#[cfg(feature = "parsing")] +use crate::buffer::Cursor; +use crate::thread::ThreadBound; +use proc_macro2::{ + Delimiter, Group, Ident, LexError, Literal, Punct, Spacing, Span, TokenStream, TokenTree, +}; +#[cfg(feature = "printing")] +use quote::ToTokens; +use std::fmt::{self, Debug, Display}; +use std::slice; +use std::vec; + +/// The result of a Syn parser. +pub type Result = std::result::Result; + +/// Error returned when a Syn parser cannot parse the input tokens. +/// +/// # Error reporting in proc macros +/// +/// The correct way to report errors back to the compiler from a procedural +/// macro is by emitting an appropriately spanned invocation of +/// [`compile_error!`] in the generated code. This produces a better diagnostic +/// message than simply panicking the macro. +/// +/// [`compile_error!`]: std::compile_error! +/// +/// When parsing macro input, the [`parse_macro_input!`] macro handles the +/// conversion to `compile_error!` automatically. +/// +/// [`parse_macro_input!`]: crate::parse_macro_input! +/// +/// ``` +/// # extern crate proc_macro; +/// # +/// use proc_macro::TokenStream; +/// use syn::parse::{Parse, ParseStream, Result}; +/// use syn::{parse_macro_input, ItemFn}; +/// +/// # const IGNORE: &str = stringify! { +/// #[proc_macro_attribute] +/// # }; +/// pub fn my_attr(args: TokenStream, input: TokenStream) -> TokenStream { +/// let args = parse_macro_input!(args as MyAttrArgs); +/// let input = parse_macro_input!(input as ItemFn); +/// +/// /* ... */ +/// # TokenStream::new() +/// } +/// +/// struct MyAttrArgs { +/// # _k: [(); { stringify! { +/// ... +/// # }; 0 }] +/// } +/// +/// impl Parse for MyAttrArgs { +/// fn parse(input: ParseStream) -> Result { +/// # stringify! { +/// ... +/// # }; +/// # unimplemented!() +/// } +/// } +/// ``` +/// +/// For errors that arise later than the initial parsing stage, the +/// [`.to_compile_error()`] or [`.into_compile_error()`] methods can be used to +/// perform an explicit conversion to `compile_error!`. +/// +/// [`.to_compile_error()`]: Error::to_compile_error +/// [`.into_compile_error()`]: Error::into_compile_error +/// +/// ``` +/// # extern crate proc_macro; +/// # +/// # use proc_macro::TokenStream; +/// # use syn::{parse_macro_input, DeriveInput}; +/// # +/// # const IGNORE: &str = stringify! { +/// #[proc_macro_derive(MyDerive)] +/// # }; +/// pub fn my_derive(input: TokenStream) -> TokenStream { +/// let input = parse_macro_input!(input as DeriveInput); +/// +/// // fn(DeriveInput) -> syn::Result +/// expand::my_derive(input) +/// .unwrap_or_else(syn::Error::into_compile_error) +/// .into() +/// } +/// # +/// # mod expand { +/// # use proc_macro2::TokenStream; +/// # use syn::{DeriveInput, Result}; +/// # +/// # pub fn my_derive(input: DeriveInput) -> Result { +/// # unimplemented!() +/// # } +/// # } +/// ``` +pub struct Error { + messages: Vec, +} + +struct ErrorMessage { + // Span is implemented as an index into a thread-local interner to keep the + // size small. It is not safe to access from a different thread. We want + // errors to be Send and Sync to play nicely with ecosystem crates for error + // handling, so pin the span we're given to its original thread and assume + // it is Span::call_site if accessed from any other thread. + span: ThreadBound, + message: String, +} + +// Cannot use std::ops::Range because that does not implement Copy, +// whereas ThreadBound requires a Copy impl as a way to ensure no Drop impls +// are involved. +struct SpanRange { + start: Span, + end: Span, +} + +#[cfg(test)] +struct _Test +where + Error: Send + Sync; + +impl Error { + /// Usually the [`ParseStream::error`] method will be used instead, which + /// automatically uses the correct span from the current position of the + /// parse stream. + /// + /// Use `Error::new` when the error needs to be triggered on some span other + /// than where the parse stream is currently positioned. + /// + /// [`ParseStream::error`]: crate::parse::ParseBuffer::error + /// + /// # Example + /// + /// ``` + /// use syn::{Error, Ident, LitStr, Result, Token}; + /// use syn::parse::ParseStream; + /// + /// // Parses input that looks like `name = "string"` where the key must be + /// // the identifier `name` and the value may be any string literal. + /// // Returns the string literal. + /// fn parse_name(input: ParseStream) -> Result { + /// let name_token: Ident = input.parse()?; + /// if name_token != "name" { + /// // Trigger an error not on the current position of the stream, + /// // but on the position of the unexpected identifier. + /// return Err(Error::new(name_token.span(), "expected `name`")); + /// } + /// input.parse::()?; + /// let s: LitStr = input.parse()?; + /// Ok(s) + /// } + /// ``` + pub fn new(span: Span, message: T) -> Self { + return new(span, message.to_string()); + + fn new(span: Span, message: String) -> Error { + Error { + messages: vec![ErrorMessage { + span: ThreadBound::new(SpanRange { + start: span, + end: span, + }), + message, + }], + } + } + } + + /// Creates an error with the specified message spanning the given syntax + /// tree node. + /// + /// Unlike the `Error::new` constructor, this constructor takes an argument + /// `tokens` which is a syntax tree node. This allows the resulting `Error` + /// to attempt to span all tokens inside of `tokens`. While you would + /// typically be able to use the `Spanned` trait with the above `Error::new` + /// constructor, implementation limitations today mean that + /// `Error::new_spanned` may provide a higher-quality error message on + /// stable Rust. + /// + /// When in doubt it's recommended to stick to `Error::new` (or + /// `ParseStream::error`)! + #[cfg(feature = "printing")] + #[cfg_attr(docsrs, doc(cfg(feature = "printing")))] + pub fn new_spanned(tokens: T, message: U) -> Self { + return new_spanned(tokens.into_token_stream(), message.to_string()); + + fn new_spanned(tokens: TokenStream, message: String) -> Error { + let mut iter = tokens.into_iter(); + let start = iter.next().map_or_else(Span::call_site, |t| t.span()); + let end = iter.last().map_or(start, |t| t.span()); + Error { + messages: vec![ErrorMessage { + span: ThreadBound::new(SpanRange { start, end }), + message, + }], + } + } + } + + /// The source location of the error. + /// + /// Spans are not thread-safe so this function returns `Span::call_site()` + /// if called from a different thread than the one on which the `Error` was + /// originally created. + pub fn span(&self) -> Span { + let SpanRange { start, end } = match self.messages[0].span.get() { + Some(span) => *span, + None => return Span::call_site(), + }; + start.join(end).unwrap_or(start) + } + + /// Render the error as an invocation of [`compile_error!`]. + /// + /// The [`parse_macro_input!`] macro provides a convenient way to invoke + /// this method correctly in a procedural macro. + /// + /// [`compile_error!`]: std::compile_error! + /// [`parse_macro_input!`]: crate::parse_macro_input! + pub fn to_compile_error(&self) -> TokenStream { + self.messages + .iter() + .map(ErrorMessage::to_compile_error) + .collect() + } + + /// Render the error as an invocation of [`compile_error!`]. + /// + /// [`compile_error!`]: std::compile_error! + /// + /// # Example + /// + /// ``` + /// # extern crate proc_macro; + /// # + /// use proc_macro::TokenStream; + /// use syn::{parse_macro_input, DeriveInput, Error}; + /// + /// # const _: &str = stringify! { + /// #[proc_macro_derive(MyTrait)] + /// # }; + /// pub fn derive_my_trait(input: TokenStream) -> TokenStream { + /// let input = parse_macro_input!(input as DeriveInput); + /// my_trait::expand(input) + /// .unwrap_or_else(Error::into_compile_error) + /// .into() + /// } + /// + /// mod my_trait { + /// use proc_macro2::TokenStream; + /// use syn::{DeriveInput, Result}; + /// + /// pub(crate) fn expand(input: DeriveInput) -> Result { + /// /* ... */ + /// # unimplemented!() + /// } + /// } + /// ``` + pub fn into_compile_error(self) -> TokenStream { + self.to_compile_error() + } + + /// Add another error message to self such that when `to_compile_error()` is + /// called, both errors will be emitted together. + pub fn combine(&mut self, another: Error) { + self.messages.extend(another.messages); + } +} + +impl ErrorMessage { + fn to_compile_error(&self) -> TokenStream { + let (start, end) = match self.span.get() { + Some(range) => (range.start, range.end), + None => (Span::call_site(), Span::call_site()), + }; + + // ::core::compile_error!($message) + TokenStream::from_iter([ + TokenTree::Punct({ + let mut punct = Punct::new(':', Spacing::Joint); + punct.set_span(start); + punct + }), + TokenTree::Punct({ + let mut punct = Punct::new(':', Spacing::Alone); + punct.set_span(start); + punct + }), + TokenTree::Ident(Ident::new("core", start)), + TokenTree::Punct({ + let mut punct = Punct::new(':', Spacing::Joint); + punct.set_span(start); + punct + }), + TokenTree::Punct({ + let mut punct = Punct::new(':', Spacing::Alone); + punct.set_span(start); + punct + }), + TokenTree::Ident(Ident::new("compile_error", start)), + TokenTree::Punct({ + let mut punct = Punct::new('!', Spacing::Alone); + punct.set_span(start); + punct + }), + TokenTree::Group({ + let mut group = Group::new(Delimiter::Brace, { + TokenStream::from_iter([TokenTree::Literal({ + let mut string = Literal::string(&self.message); + string.set_span(end); + string + })]) + }); + group.set_span(end); + group + }), + ]) + } +} + +#[cfg(feature = "parsing")] +pub(crate) fn new_at(scope: Span, cursor: Cursor, message: T) -> Error { + if cursor.eof() { + Error::new(scope, format!("unexpected end of input, {}", message)) + } else { + let span = crate::buffer::open_span_of_group(cursor); + Error::new(span, message) + } +} + +#[cfg(all(feature = "parsing", any(feature = "full", feature = "derive")))] +pub(crate) fn new2(start: Span, end: Span, message: T) -> Error { + return new2(start, end, message.to_string()); + + fn new2(start: Span, end: Span, message: String) -> Error { + Error { + messages: vec![ErrorMessage { + span: ThreadBound::new(SpanRange { start, end }), + message, + }], + } + } +} + +impl Debug for Error { + fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result { + if self.messages.len() == 1 { + formatter + .debug_tuple("Error") + .field(&self.messages[0]) + .finish() + } else { + formatter + .debug_tuple("Error") + .field(&self.messages) + .finish() + } + } +} + +impl Debug for ErrorMessage { + fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result { + Debug::fmt(&self.message, formatter) + } +} + +impl Display for Error { + fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result { + formatter.write_str(&self.messages[0].message) + } +} + +impl Clone for Error { + fn clone(&self) -> Self { + Error { + messages: self.messages.clone(), + } + } +} + +impl Clone for ErrorMessage { + fn clone(&self) -> Self { + ErrorMessage { + span: self.span, + message: self.message.clone(), + } + } +} + +impl Clone for SpanRange { + fn clone(&self) -> Self { + *self + } +} + +impl Copy for SpanRange {} + +impl std::error::Error for Error {} + +impl From for Error { + fn from(err: LexError) -> Self { + Error::new(err.span(), err) + } +} + +impl IntoIterator for Error { + type Item = Error; + type IntoIter = IntoIter; + + fn into_iter(self) -> Self::IntoIter { + IntoIter { + messages: self.messages.into_iter(), + } + } +} + +pub struct IntoIter { + messages: vec::IntoIter, +} + +impl Iterator for IntoIter { + type Item = Error; + + fn next(&mut self) -> Option { + Some(Error { + messages: vec![self.messages.next()?], + }) + } +} + +impl<'a> IntoIterator for &'a Error { + type Item = Error; + type IntoIter = Iter<'a>; + + fn into_iter(self) -> Self::IntoIter { + Iter { + messages: self.messages.iter(), + } + } +} + +pub struct Iter<'a> { + messages: slice::Iter<'a, ErrorMessage>, +} + +impl<'a> Iterator for Iter<'a> { + type Item = Error; + + fn next(&mut self) -> Option { + Some(Error { + messages: vec![self.messages.next()?.clone()], + }) + } +} + +impl Extend for Error { + fn extend>(&mut self, iter: T) { + for err in iter { + self.combine(err); + } + } +} -- cgit v1.3.1