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/scan_expr.rs | 267 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 267 insertions(+) create mode 100644 rust/syn/scan_expr.rs (limited to 'rust/syn/scan_expr.rs') diff --git a/rust/syn/scan_expr.rs b/rust/syn/scan_expr.rs new file mode 100644 index 000000000..a5fd1ddc1 --- /dev/null +++ b/rust/syn/scan_expr.rs @@ -0,0 +1,267 @@ +// SPDX-License-Identifier: Apache-2.0 OR MIT + +use self::{Action::*, Input::*}; +use proc_macro2::{Delimiter, Ident, Spacing, TokenTree}; +use syn::parse::{ParseStream, Result}; +use syn::{AngleBracketedGenericArguments, BinOp, Expr, ExprPath, Lifetime, Lit, Token, Type}; + +enum Input { + Keyword(&'static str), + Punct(&'static str), + ConsumeAny, + ConsumeBinOp, + ConsumeBrace, + ConsumeDelimiter, + ConsumeIdent, + ConsumeLifetime, + ConsumeLiteral, + ConsumeNestedBrace, + ExpectPath, + ExpectTurbofish, + ExpectType, + CanBeginExpr, + Otherwise, + Empty, +} + +enum Action { + SetState(&'static [(Input, Action)]), + IncDepth, + DecDepth, + Finish, +} + +static INIT: [(Input, Action); 28] = [ + (ConsumeDelimiter, SetState(&POSTFIX)), + (Keyword("async"), SetState(&ASYNC)), + (Keyword("break"), SetState(&BREAK_LABEL)), + (Keyword("const"), SetState(&CONST)), + (Keyword("continue"), SetState(&CONTINUE)), + (Keyword("for"), SetState(&FOR)), + (Keyword("if"), IncDepth), + (Keyword("let"), SetState(&PATTERN)), + (Keyword("loop"), SetState(&BLOCK)), + (Keyword("match"), IncDepth), + (Keyword("move"), SetState(&CLOSURE)), + (Keyword("return"), SetState(&RETURN)), + (Keyword("static"), SetState(&CLOSURE)), + (Keyword("unsafe"), SetState(&BLOCK)), + (Keyword("while"), IncDepth), + (Keyword("yield"), SetState(&RETURN)), + (Keyword("_"), SetState(&POSTFIX)), + (Punct("!"), SetState(&INIT)), + (Punct("#"), SetState(&[(ConsumeDelimiter, SetState(&INIT))])), + (Punct("&"), SetState(&REFERENCE)), + (Punct("*"), SetState(&INIT)), + (Punct("-"), SetState(&INIT)), + (Punct("..="), SetState(&INIT)), + (Punct(".."), SetState(&RANGE)), + (Punct("|"), SetState(&CLOSURE_ARGS)), + (ConsumeLifetime, SetState(&[(Punct(":"), SetState(&INIT))])), + (ConsumeLiteral, SetState(&POSTFIX)), + (ExpectPath, SetState(&PATH)), +]; + +static POSTFIX: [(Input, Action); 10] = [ + (Keyword("as"), SetState(&[(ExpectType, SetState(&POSTFIX))])), + (Punct("..="), SetState(&INIT)), + (Punct(".."), SetState(&RANGE)), + (Punct("."), SetState(&DOT)), + (Punct("?"), SetState(&POSTFIX)), + (ConsumeBinOp, SetState(&INIT)), + (Punct("="), SetState(&INIT)), + (ConsumeNestedBrace, SetState(&IF_THEN)), + (ConsumeDelimiter, SetState(&POSTFIX)), + (Empty, Finish), +]; + +static ASYNC: [(Input, Action); 3] = [ + (Keyword("move"), SetState(&ASYNC)), + (Punct("|"), SetState(&CLOSURE_ARGS)), + (ConsumeBrace, SetState(&POSTFIX)), +]; + +static BLOCK: [(Input, Action); 1] = [(ConsumeBrace, SetState(&POSTFIX))]; + +static BREAK_LABEL: [(Input, Action); 2] = [ + (ConsumeLifetime, SetState(&BREAK_VALUE)), + (Otherwise, SetState(&BREAK_VALUE)), +]; + +static BREAK_VALUE: [(Input, Action); 3] = [ + (ConsumeNestedBrace, SetState(&IF_THEN)), + (CanBeginExpr, SetState(&INIT)), + (Otherwise, SetState(&POSTFIX)), +]; + +static CLOSURE: [(Input, Action); 7] = [ + (Keyword("async"), SetState(&CLOSURE)), + (Keyword("move"), SetState(&CLOSURE)), + (Punct(","), SetState(&CLOSURE)), + (Punct(">"), SetState(&CLOSURE)), + (Punct("|"), SetState(&CLOSURE_ARGS)), + (ConsumeLifetime, SetState(&CLOSURE)), + (ConsumeIdent, SetState(&CLOSURE)), +]; + +static CLOSURE_ARGS: [(Input, Action); 2] = [ + (Punct("|"), SetState(&CLOSURE_RET)), + (ConsumeAny, SetState(&CLOSURE_ARGS)), +]; + +static CLOSURE_RET: [(Input, Action); 2] = [ + (Punct("->"), SetState(&[(ExpectType, SetState(&BLOCK))])), + (Otherwise, SetState(&INIT)), +]; + +static CONST: [(Input, Action); 2] = [ + (Punct("|"), SetState(&CLOSURE_ARGS)), + (ConsumeBrace, SetState(&POSTFIX)), +]; + +static CONTINUE: [(Input, Action); 2] = [ + (ConsumeLifetime, SetState(&POSTFIX)), + (Otherwise, SetState(&POSTFIX)), +]; + +static DOT: [(Input, Action); 3] = [ + (Keyword("await"), SetState(&POSTFIX)), + (ConsumeIdent, SetState(&METHOD)), + (ConsumeLiteral, SetState(&POSTFIX)), +]; + +static FOR: [(Input, Action); 2] = [ + (Punct("<"), SetState(&CLOSURE)), + (Otherwise, SetState(&PATTERN)), +]; + +static IF_ELSE: [(Input, Action); 2] = [(Keyword("if"), SetState(&INIT)), (ConsumeBrace, DecDepth)]; +static IF_THEN: [(Input, Action); 2] = + [(Keyword("else"), SetState(&IF_ELSE)), (Otherwise, DecDepth)]; + +static METHOD: [(Input, Action); 1] = [(ExpectTurbofish, SetState(&POSTFIX))]; + +static PATH: [(Input, Action); 4] = [ + (Punct("!="), SetState(&INIT)), + (Punct("!"), SetState(&INIT)), + (ConsumeNestedBrace, SetState(&IF_THEN)), + (Otherwise, SetState(&POSTFIX)), +]; + +static PATTERN: [(Input, Action); 15] = [ + (ConsumeDelimiter, SetState(&PATTERN)), + (Keyword("box"), SetState(&PATTERN)), + (Keyword("in"), IncDepth), + (Keyword("mut"), SetState(&PATTERN)), + (Keyword("ref"), SetState(&PATTERN)), + (Keyword("_"), SetState(&PATTERN)), + (Punct("!"), SetState(&PATTERN)), + (Punct("&"), SetState(&PATTERN)), + (Punct("..="), SetState(&PATTERN)), + (Punct(".."), SetState(&PATTERN)), + (Punct("="), SetState(&INIT)), + (Punct("@"), SetState(&PATTERN)), + (Punct("|"), SetState(&PATTERN)), + (ConsumeLiteral, SetState(&PATTERN)), + (ExpectPath, SetState(&PATTERN)), +]; + +static RANGE: [(Input, Action); 6] = [ + (Punct("..="), SetState(&INIT)), + (Punct(".."), SetState(&RANGE)), + (Punct("."), SetState(&DOT)), + (ConsumeNestedBrace, SetState(&IF_THEN)), + (Empty, Finish), + (Otherwise, SetState(&INIT)), +]; + +static RAW: [(Input, Action); 3] = [ + (Keyword("const"), SetState(&INIT)), + (Keyword("mut"), SetState(&INIT)), + (Otherwise, SetState(&POSTFIX)), +]; + +static REFERENCE: [(Input, Action); 3] = [ + (Keyword("mut"), SetState(&INIT)), + (Keyword("raw"), SetState(&RAW)), + (Otherwise, SetState(&INIT)), +]; + +static RETURN: [(Input, Action); 2] = [ + (CanBeginExpr, SetState(&INIT)), + (Otherwise, SetState(&POSTFIX)), +]; + +pub(crate) fn scan_expr(input: ParseStream) -> Result<()> { + let mut state = INIT.as_slice(); + let mut depth = 0usize; + 'table: loop { + for rule in state { + if match rule.0 { + Input::Keyword(expected) => input.step(|cursor| match cursor.ident() { + Some((ident, rest)) if ident == expected => Ok((true, rest)), + _ => Ok((false, *cursor)), + })?, + Input::Punct(expected) => input.step(|cursor| { + let begin = *cursor; + let mut cursor = begin; + for (i, ch) in expected.chars().enumerate() { + match cursor.punct() { + Some((punct, _)) if punct.as_char() != ch => break, + Some((_, rest)) if i == expected.len() - 1 => { + return Ok((true, rest)); + } + Some((punct, rest)) if punct.spacing() == Spacing::Joint => { + cursor = rest; + } + _ => break, + } + } + Ok((false, begin)) + })?, + Input::ConsumeAny => input.parse::>()?.is_some(), + Input::ConsumeBinOp => input.parse::().is_ok(), + Input::ConsumeBrace | Input::ConsumeNestedBrace => { + (matches!(rule.0, Input::ConsumeBrace) || depth > 0) + && input.step(|cursor| match cursor.group(Delimiter::Brace) { + Some((_inside, _span, rest)) => Ok((true, rest)), + None => Ok((false, *cursor)), + })? + } + Input::ConsumeDelimiter => input.step(|cursor| match cursor.any_group() { + Some((_inside, _delimiter, _span, rest)) => Ok((true, rest)), + None => Ok((false, *cursor)), + })?, + Input::ConsumeIdent => input.parse::>()?.is_some(), + Input::ConsumeLifetime => input.parse::>()?.is_some(), + Input::ConsumeLiteral => input.parse::>()?.is_some(), + Input::ExpectPath => { + input.parse::()?; + true + } + Input::ExpectTurbofish => { + if input.peek(Token![::]) { + input.parse::()?; + } + true + } + Input::ExpectType => { + Type::without_plus(input)?; + true + } + Input::CanBeginExpr => Expr::peek(input), + Input::Otherwise => true, + Input::Empty => input.is_empty() || input.peek(Token![,]), + } { + state = match rule.1 { + Action::SetState(next) => next, + Action::IncDepth => (depth += 1, &INIT).1, + Action::DecDepth => (depth -= 1, &POSTFIX).1, + Action::Finish => return if depth == 0 { Ok(()) } else { break }, + }; + continue 'table; + } + } + return Err(input.error("unsupported expression")); + } +} -- cgit v1.3.1