diff --git a/shrinkwrap/commands/run.py b/shrinkwrap/commands/run.py
index 3fa9d40776c3a36f090aced073ced9124a9c134e..699d8de718c60a4e48f04fb4aef394a1e47a81ad 100644
--- a/shrinkwrap/commands/run.py
+++ b/shrinkwrap/commands/run.py
@@ -61,6 +61,12 @@ def add_parser(parser, formatter):
 		required=False, default=False, action='store_true',
 		help="""If specified, logs will not be colorized.""")
 
+	cmdp.add_argument('-t', '--timeout',
+		required=False, default=None, type=int,
+		help="""Number of days after which to automatically shutdown the
+		     container, if using a container runtime. Defaults to 1 day.
+		     """)
+
 	return cmd_name
 
 
@@ -229,7 +235,8 @@ def dispatch(args):
 	# on the host or may execute commands in a container, depending on what
 	# the user specified.
 	with runtime.Runtime(name=args.runtime, image=config.get_image([resolveb], args),
-		       		ssh_agent_keys=args.ssh_agent_keys) as rt:
+		       		ssh_agent_keys=args.ssh_agent_keys,
+				timeout=args.timeout) as rt:
 		for rtvar in resolver['run']['rtvars'].values():
 			if rtvar['type'] == 'path':
 				rt.add_volume(rtvar['value'])
diff --git a/shrinkwrap/utils/runtime.py b/shrinkwrap/utils/runtime.py
index 52be6942a9c14c1f2edfbe43c5bca967d2d2f9fd..e8c5342668ca2f1f0ca6f59945f2dd6f6086f6dc 100644
--- a/shrinkwrap/utils/runtime.py
+++ b/shrinkwrap/utils/runtime.py
@@ -25,9 +25,11 @@ class Runtime:
 	an abstracted runtime. Multiple runtimes are supported, identified by a
 	`name`. The 'null' runtime simply executes the commands on the native
 	host. The 'docker', 'docker-local', 'podman' and 'podman-local' runtimes
-	execute the commands in a container.
+	execute the commands in a container. `timeout`, if provided, is an
+	integer number of days after which the container will be shutdown if
+	still running. If None, the default timeout is used.
 	"""
-	def __init__(self, *, name, image=None, ssh_agent_keys=None):
+	def __init__(self, *, name, image=None, ssh_agent_keys=None, timeout=None):
 		self._rt = None
 		self._mountpoints = set()
 
@@ -36,6 +38,7 @@ class Runtime:
 
 		is_mac = sys.platform.startswith('darwin')
 		is_docker = name.startswith('docker')
+		is_container = is_docker or name.startswith('podman')
 
 		# MacOS uses GIDs that overlap with already defined GIDs in the
 		# container so we can't just bind the macos host UID/GID to the
@@ -57,6 +60,23 @@ class Runtime:
 			self._rt.set_user('shrinkwrap')
 			self._rt.set_group('shrinkwrap')
 
+		# Tuxmake always starts the container with "sleep 1d" so that it
+		# automatically shuts down after 1 day if it ends up dangling.
+		# This is problematic for some long running FVP test cases, so
+		# we allow overriding it on the command line. We add a filter
+		# for spawn_container() which modifies the sleep argument which
+		# is the last element in the cmd list. Avoid hooking unless the
+		# user explicitly specified a timeout that is different from the
+		# expected default.
+		if is_container and timeout and timeout != 1:
+			spawn_container_orig = self._rt.spawn_container
+			def spawn_container_new(self, cmd):
+				if (cmd[-1] == '1d'):
+					cmd[-1] = f'{timeout}d'
+				return spawn_container_orig(cmd)
+			self._rt.spawn_container = \
+				types.MethodType(spawn_container_new, self._rt)
+
 		for key in ssh_agent_keys:
 			ssh_agent_lib.add(key)
 
@@ -143,7 +163,13 @@ print(ip)
 		assert _instance == self
 		_instance = None
 		if self._rt:
-			self._rt.cleanup()
+			# Horrible hack alert; I've observed that docker can
+			# take over 10 seconds to stop the container on at least
+			# 1 system running Ubuntu 24.04. Let's cleanup the
+			# container asynchonously in a child process.
+			if os.fork() == 0:
+				self._rt.cleanup()
+				exit()
 			self._rt = None