https://github.com/kadircet created https://github.com/llvm/llvm-project/pull/130077
We started seeing some use-after-frees starting with https://github.com/llvm/llvm-project/pull/125433. This patch ensures we explicitly block for the async task, if there's one, before destructing `std::future`, independent of the stdlib implementation. From 9242c82981c46bd1c19b65c9be3a142cdd605d9b Mon Sep 17 00:00:00 2001 From: Kadir Cetinkaya <kadir...@google.com> Date: Thu, 6 Mar 2025 12:20:44 +0100 Subject: [PATCH] [clangd] Explicitly block until async task completes --- clang-tools-extra/clangd/ClangdServer.cpp | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/clang-tools-extra/clangd/ClangdServer.cpp b/clang-tools-extra/clangd/ClangdServer.cpp index 52be15d3da936..49a97da2bfa42 100644 --- a/clang-tools-extra/clangd/ClangdServer.cpp +++ b/clang-tools-extra/clangd/ClangdServer.cpp @@ -460,18 +460,24 @@ void ClangdServer::codeComplete(PathRef File, Position Pos, CodeCompleteResult Result = clangd::codeComplete( File, Pos, IP->Preamble, ParseInput, CodeCompleteOpts, SpecFuzzyFind ? &*SpecFuzzyFind : nullptr); + // We don't want `codeComplete` to wait for the async call if it doesn't use + // the result (e.g. non-index completion, speculation fails), so that `CB` + // is called as soon as results are available. { clang::clangd::trace::Span Tracer("Completion results callback"); CB(std::move(Result)); } - if (SpecFuzzyFind && SpecFuzzyFind->NewReq) { + if (!SpecFuzzyFind) + return; + if (SpecFuzzyFind->NewReq) { std::lock_guard<std::mutex> Lock(CachedCompletionFuzzyFindRequestMutex); CachedCompletionFuzzyFindRequestByFile[File] = *SpecFuzzyFind->NewReq; } - // SpecFuzzyFind is only destroyed after speculative fuzzy find finishes. - // We don't want `codeComplete` to wait for the async call if it doesn't use - // the result (e.g. non-index completion, speculation fails), so that `CB` - // is called as soon as results are available. + // Explicitly block until async task completes, this is fine as we've + // already provided reply to the client and running as a preamble task + // (i.e. won't block other preamble tasks). + if (SpecFuzzyFind->Result.valid()) + SpecFuzzyFind->Result.wait(); }; // We use a potentially-stale preamble because latency is critical here. _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
