From da78b8e8a15b3cb059bab11f6012e1cebfebf5c8 Mon Sep 17 00:00:00 2001
From: Jordan Dominion <Cyberboss@users.noreply.github.com>
Date: Sun, 3 Dec 2023 14:53:45 -0500
Subject: [PATCH] Fix deadlock with `DumpOnHealthCheckRestart`

---
 .../Components/Watchdog/WatchdogBase.cs       | 54 +++++++++++--------
 1 file changed, 31 insertions(+), 23 deletions(-)

diff --git a/src/Tgstation.Server.Host/Components/Watchdog/WatchdogBase.cs b/src/Tgstation.Server.Host/Components/Watchdog/WatchdogBase.cs
index 59aebe0c57..60b3deb05f 100644
--- a/src/Tgstation.Server.Host/Components/Watchdog/WatchdogBase.cs
+++ b/src/Tgstation.Server.Host/Components/Watchdog/WatchdogBase.cs
@@ -446,29 +446,8 @@ namespace Tgstation.Server.Host.Components.Watchdog
 		/// <inheritdoc />
 		public async ValueTask CreateDump(CancellationToken cancellationToken)
 		{
-			const string DumpDirectory = "ProcessDumps";
 			using (await SemaphoreSlimContext.Lock(synchronizationSemaphore, cancellationToken))
-			{
-				var dumpFileNameTemplate = diagnosticsIOManager.ResolvePath(
-					diagnosticsIOManager.ConcatPath(
-						DumpDirectory,
-						$"DreamDaemon-{DateTimeOffset.UtcNow.ToFileStamp()}.dmp"));
-
-				var dumpFileName = dumpFileNameTemplate;
-				var iteration = 0;
-				while (await diagnosticsIOManager.FileExists(dumpFileName, cancellationToken))
-					dumpFileName = $"{dumpFileNameTemplate} ({++iteration})";
-
-				if (iteration == 0)
-					await diagnosticsIOManager.CreateDirectory(DumpDirectory, cancellationToken);
-
-				var session = GetActiveController();
-				if (session?.Lifetime.IsCompleted != false)
-					throw new JobException(ErrorCode.GameServerOffline);
-
-				Logger.LogInformation("Dumping session to {dumpFileName}...", dumpFileName);
-				await session.CreateDump(dumpFileName, cancellationToken);
-			}
+				await CreateDumpNoLock(cancellationToken);
 		}
 
 		/// <inheritdoc />
@@ -1153,7 +1132,7 @@ namespace Tgstation.Server.Host.Components.Watchdog
 							Logger.LogDebug("DumpOnHealthCheckRestart enabled.");
 							try
 							{
-								await CreateDump(cancellationToken);
+								await CreateDumpNoLock(cancellationToken);
 							}
 							catch (JobException ex)
 							{
@@ -1203,5 +1182,34 @@ namespace Tgstation.Server.Host.Components.Watchdog
 							.Where(nullableChannelId => nullableChannelId.HasValue)
 							.Select(nullableChannelId => nullableChannelId.Value));
 		}
+
+		/// <summary>
+		/// Attempt to create a process dump for the game server. Requires a lock on <see cref="synchronizationSemaphore"/>.
+		/// </summary>
+		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
+		/// <returns>A <see cref="ValueTask"/> representing the running operation.</returns>
+		async ValueTask CreateDumpNoLock(CancellationToken cancellationToken)
+		{
+			const string DumpDirectory = "ProcessDumps";
+			var dumpFileNameTemplate = diagnosticsIOManager.ResolvePath(
+				diagnosticsIOManager.ConcatPath(
+					DumpDirectory,
+					$"DreamDaemon-{DateTimeOffset.UtcNow.ToFileStamp()}.dmp"));
+
+			var dumpFileName = dumpFileNameTemplate;
+			var iteration = 0;
+			while (await diagnosticsIOManager.FileExists(dumpFileName, cancellationToken))
+				dumpFileName = $"{dumpFileNameTemplate} ({++iteration})";
+
+			if (iteration == 0)
+				await diagnosticsIOManager.CreateDirectory(DumpDirectory, cancellationToken);
+
+			var session = GetActiveController();
+			if (session?.Lifetime.IsCompleted != false)
+				throw new JobException(ErrorCode.GameServerOffline);
+
+			Logger.LogInformation("Dumping session to {dumpFileName}...", dumpFileName);
+			await session.CreateDump(dumpFileName, cancellationToken);
+		}
 	}
 }