https://github.com/jeffreytan81 created https://github.com/llvm/llvm-project/pull/104195
This PR fixes a potential race condition in https://github.com/llvm/llvm-project/pull/90930. This race can happen because the original code set `m_info->m_isAlive = true` **after** the timer thread is created. So if there is a context switch happens and timer thread checks `m_info->m_isAlive` before main thread got a chance to run `m_info->m_isAlive = true`, the timer thread may treat `ThreadPlanSingleThreadTimeout` as not alive and simply exit. >From 5d413e737dd522603ab22105946671d95dc2d038 Mon Sep 17 00:00:00 2001 From: jeffreytan81 <jeffrey...@fb.com> Date: Wed, 14 Aug 2024 12:17:22 -0700 Subject: [PATCH] Fix single thread stepping timeout race condition --- lldb/source/Target/ThreadPlanSingleThreadTimeout.cpp | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/lldb/source/Target/ThreadPlanSingleThreadTimeout.cpp b/lldb/source/Target/ThreadPlanSingleThreadTimeout.cpp index 0a939d55f4ce49..806ba95c508b7c 100644 --- a/lldb/source/Target/ThreadPlanSingleThreadTimeout.cpp +++ b/lldb/source/Target/ThreadPlanSingleThreadTimeout.cpp @@ -29,10 +29,10 @@ ThreadPlanSingleThreadTimeout::ThreadPlanSingleThreadTimeout( : ThreadPlan(ThreadPlan::eKindSingleThreadTimeout, "Single thread timeout", thread, eVoteNo, eVoteNoOpinion), m_info(info), m_state(State::WaitTimeout) { - // TODO: reuse m_timer_thread without recreation. - m_timer_thread = std::thread(TimeoutThreadFunc, this); m_info->m_isAlive = true; m_state = m_info->m_last_state; + // TODO: reuse m_timer_thread without recreation. + m_timer_thread = std::thread(TimeoutThreadFunc, this); } ThreadPlanSingleThreadTimeout::~ThreadPlanSingleThreadTimeout() { _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
