https://github.com/royitaqi created
https://github.com/llvm/llvm-project/pull/151828
# Problem
When the user changes lldb-dap's arguments (e.g. path), there is a race
condition, where the new lldb-dap process could be started first and have set
the extension's `serverProcess` and `serverInfo` according to the new process,
while the old lldb-dap process exits later and wipes out these two fields.
Consequences:
1. This causes `getServerProcess()` to return `undefined` when it should return
the new process.
2. This also causes wrong behavior in the next debug session that a new
lldb-dap process will be started and the old not reused nor killed.
# Fix
When wiping the two fields, check if `serverProcess` equals to the process
captured by the handler. If they equal, wipe the fields. If not, then the
fields have already been updated (either new process has started, or the fields
were already wiped out by another handler), and so the wiping should be skipped.
>From b58e5d4fe42a499dc7b9d903f56d62fc993f67a2 Mon Sep 17 00:00:00 2001
From: Roy Shi <roy...@meta.com>
Date: Sat, 2 Aug 2025 09:30:25 -0700
Subject: [PATCH] [vscode-lldb] Fix race condition when changing lldb-dap
arguments
---
lldb/tools/lldb-dap/src-ts/lldb-dap-server.ts | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/lldb/tools/lldb-dap/src-ts/lldb-dap-server.ts
b/lldb/tools/lldb-dap/src-ts/lldb-dap-server.ts
index 79573ec7342b1..c4e99a3178e8c 100644
--- a/lldb/tools/lldb-dap/src-ts/lldb-dap-server.ts
+++ b/lldb/tools/lldb-dap/src-ts/lldb-dap-server.ts
@@ -39,8 +39,10 @@ export class LLDBDapServer implements vscode.Disposable {
const process = child_process.spawn(dapPath, dapArgs, options);
process.on("error", (error) => {
reject(error);
- this.serverProcess = undefined;
- this.serverInfo = undefined;
+ if (this.serverProcess === process) {
+ this.serverProcess = undefined;
+ this.serverInfo = undefined;
+ }
});
process.on("exit", (code, signal) => {
let errorMessage = "Server process exited early";
@@ -50,8 +52,10 @@ export class LLDBDapServer implements vscode.Disposable {
errorMessage += ` due to signal ${signal}`;
}
reject(new Error(errorMessage));
- this.serverProcess = undefined;
- this.serverInfo = undefined;
+ if (this.serverProcess === process) {
+ this.serverProcess = undefined;
+ this.serverInfo = undefined;
+ }
});
process.stdout.setEncoding("utf8").on("data", (data) => {
const connection = /connection:\/\/\[([^\]]+)\]:(\d+)/.exec(
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