https://github.com/da-viper created https://github.com/llvm/llvm-project/pull/163821
The modules event requires the `APIMutex` to create the module load address. this may happen at the same time the `module request` is handled. The modules request also requires the `APIMutex` and the `modules_mutex, set the order to acquire the mutexes. >From b10c3b8725a7d219f3bae07d06105ec1a28ecd13 Mon Sep 17 00:00:00 2001 From: Ebuka Ezike <[email protected]> Date: Thu, 16 Oct 2025 17:40:21 +0100 Subject: [PATCH] [lldb-dap] Fix mutex acquisition order for modules event. The modules event requires the `APIMutex` to create the module load address. this may happen at the same time the `module request` is handled. The modules request also requires the `APIMutex` and the `modules_mutex, set the order to acquire the mutexes. --- lldb/tools/lldb-dap/DAP.cpp | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/lldb/tools/lldb-dap/DAP.cpp b/lldb/tools/lldb-dap/DAP.cpp index f76656e98ca01..003b55fa31610 100644 --- a/lldb/tools/lldb-dap/DAP.cpp +++ b/lldb/tools/lldb-dap/DAP.cpp @@ -1437,7 +1437,12 @@ void DAP::EventThread() { const bool remove_module = event_mask & lldb::SBTarget::eBroadcastBitModulesUnloaded; - std::lock_guard<std::mutex> guard(modules_mutex); + // NOTE: Both mutexes must be acquired (API mutex first, then modules + // mutex) to prevent deadlock when handling `modules_request`, which + // also requires both locks. + lldb::SBMutex api_mutex = GetAPIMutex(); + std::lock_guard api_guard(api_mutex); + std::lock_guard modules_guard(modules_mutex); for (uint32_t i = 0; i < num_modules; ++i) { lldb::SBModule module = lldb::SBTarget::GetModuleAtIndexFromEvent(i, event); _______________________________________________ lldb-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
