From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- rust/syn/ext.rs | 138 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 138 insertions(+) create mode 100644 rust/syn/ext.rs (limited to 'rust/syn/ext.rs') diff --git a/rust/syn/ext.rs b/rust/syn/ext.rs new file mode 100644 index 000000000..a9be9af42 --- /dev/null +++ b/rust/syn/ext.rs @@ -0,0 +1,138 @@ +// SPDX-License-Identifier: Apache-2.0 OR MIT + +//! Extension traits to provide parsing methods on foreign types. + +use crate::buffer::Cursor; +use crate::error::Result; +use crate::parse::ParseStream; +use crate::parse::Peek; +use crate::sealed::lookahead; +use crate::token::CustomToken; +use proc_macro2::Ident; + +/// Additional methods for `Ident` not provided by proc-macro2 or libproc_macro. +/// +/// This trait is sealed and cannot be implemented for types outside of Syn. It +/// is implemented only for `proc_macro2::Ident`. +pub trait IdentExt: Sized + private::Sealed { + /// Parses any identifier including keywords. + /// + /// This is useful when parsing macro input which allows Rust keywords as + /// identifiers. + /// + /// # Example + /// + /// ``` + /// use syn::{Error, Ident, Result, Token}; + /// use syn::ext::IdentExt; + /// use syn::parse::ParseStream; + /// + /// mod kw { + /// syn::custom_keyword!(name); + /// } + /// + /// // Parses input that looks like `name = NAME` where `NAME` can be + /// // any identifier. + /// // + /// // Examples: + /// // + /// // name = anything + /// // name = impl + /// fn parse_dsl(input: ParseStream) -> Result { + /// input.parse::()?; + /// input.parse::()?; + /// let name = input.call(Ident::parse_any)?; + /// Ok(name) + /// } + /// ``` + fn parse_any(input: ParseStream) -> Result; + + /// Peeks any identifier including keywords. Usage: + /// `input.peek(Ident::peek_any)` + /// + /// This is different from `input.peek(Ident)` which only returns true in + /// the case of an ident which is not a Rust keyword. + #[allow(non_upper_case_globals)] + const peek_any: private::PeekFn = private::PeekFn; + + /// Strips the raw marker `r#`, if any, from the beginning of an ident. + /// + /// - unraw(`x`) = `x` + /// - unraw(`move`) = `move` + /// - unraw(`r#move`) = `move` + /// + /// # Example + /// + /// In the case of interop with other languages like Python that have a + /// different set of keywords than Rust, we might come across macro input + /// that involves raw identifiers to refer to ordinary variables in the + /// other language with a name that happens to be a Rust keyword. + /// + /// The function below appends an identifier from the caller's input onto a + /// fixed prefix. Without using `unraw()`, this would tend to produce + /// invalid identifiers like `__pyo3_get_r#move`. + /// + /// ``` + /// use proc_macro2::Span; + /// use syn::Ident; + /// use syn::ext::IdentExt; + /// + /// fn ident_for_getter(variable: &Ident) -> Ident { + /// let getter = format!("__pyo3_get_{}", variable.unraw()); + /// Ident::new(&getter, Span::call_site()) + /// } + /// ``` + fn unraw(&self) -> Ident; +} + +impl IdentExt for Ident { + fn parse_any(input: ParseStream) -> Result { + input.step(|cursor| match cursor.ident() { + Some((ident, rest)) => Ok((ident, rest)), + None => Err(cursor.error("expected ident")), + }) + } + + fn unraw(&self) -> Ident { + let string = self.to_string(); + if let Some(string) = string.strip_prefix("r#") { + Ident::new(string, self.span()) + } else { + self.clone() + } + } +} + +impl Peek for private::PeekFn { + type Token = private::IdentAny; +} + +impl CustomToken for private::IdentAny { + fn peek(cursor: Cursor) -> bool { + cursor.ident().is_some() + } + + fn display() -> &'static str { + "identifier" + } +} + +impl lookahead::Sealed for private::PeekFn {} + +mod private { + use proc_macro2::Ident; + + pub trait Sealed {} + + impl Sealed for Ident {} + + pub struct PeekFn; + pub struct IdentAny; + + impl Copy for PeekFn {} + impl Clone for PeekFn { + fn clone(&self) -> Self { + *self + } + } +} -- cgit v1.3.1