https://github.com/Teemperor created https://github.com/llvm/llvm-project/pull/195816
On macOS, LLDB's test suite randomly receives SIGHUP signals that stop the test suite early. The source of these SIGHUP's seems to be a bug in the kernel (most likely job control). The exact steps for reproducing this are not clear, but I have a set of three tests of which two need to run concurrently for this to trigger: * TestDAP_runInTerminal * TestDAP_launch_io_integratedTerminal * TestDAP_launch_stdio_redirection_and_console I was also running UBSan on this build which may or may not be necessary to make this random failure more persistent. When these tests run, macOS job control will send SIGHUP to the process group of the spawned subprocesses in that test. As LIT is in the same process group, it also receives the SIGHUP and shuts down. This patch just uses Python's API for forcing the spawned subprocess to its own process group. This won't stop the SIGHUP and only prevents it from reaching LIT. The SIGHUP itself doesn't seem to affect the DAP test itself. My theory here is that the SIGHUP is received during test shutdown (or after it was shut down), so that's why it doesn't cause any visible failures in any of the tests. >From 0e070ba81304b4b80337bd12ac168d538a23e75d Mon Sep 17 00:00:00 2001 From: Raphael Isemann <[email protected]> Date: Fri, 1 May 2026 10:41:43 +0100 Subject: [PATCH] [lldb][test] Move DAP processes to own group to avoid random SIGHUPs On macOS, LLDB's test suite randomly receives SIGHUP signals that stop the test suite early. The source of these SIGHUP's seems to be a bug in the kernel (most likely job control). The exact steps for reproducing this are not clear, but I have a set of three tests of which two need to run concurrently for this to trigger: * TestDAP_runInTerminal * TestDAP_launch_io_integratedTerminal * TestDAP_launch_stdio_redirection_and_console I was also running UBSan on this build which may or may not be necessary to make this random failure more persistent. When these tests run, macOS job control will send SIGHUP to the process group of the spawned subprocesses in that test. As LIT is in the same process group, it also receives the SIGHUP and shuts down. This patch just uses Python's API for forcing the spawned subprocess to its own process group. This won't stop the SIGHUP and only prevents it from reaching LIT. The SIGHUP itself doesn't seem to affect the DAP test itself. My theory here is that the SIGHUP is received during test shutdown (or after it was shut down), so that's why it doesn't cause any visible failures in any of the tests. --- .../lldbsuite/test/tools/lldb-dap/dap_server.py | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/lldb/packages/Python/lldbsuite/test/tools/lldb-dap/dap_server.py b/lldb/packages/Python/lldbsuite/test/tools/lldb-dap/dap_server.py index c8acf67b23b99..0e9f187f9fe2b 100644 --- a/lldb/packages/Python/lldbsuite/test/tools/lldb-dap/dap_server.py +++ b/lldb/packages/Python/lldbsuite/test/tools/lldb-dap/dap_server.py @@ -512,7 +512,16 @@ def _handle_reverse_request(self, request: Request) -> None: env_dict = os.environ | arguments.get("env", {}) env = [f"{k}={v}" for k, v in env_dict.items()] self.reverse_process = self.spawn_helper( - exe, args, env, stdout=subprocess.PIPE, stderr=subprocess.PIPE + exe, args, env, stdout=subprocess.PIPE, stderr=subprocess.PIPE, + # This works around a bug in the macOS job control code where + # a supurious SIGHUP is sent to the the process group of our + # spawned subprocess when it is shutting down. + # While this SIGHUP doesn't cause any issues for our subprocess, + # it does reach the LIT process and stop the test suite run + # early. + # This parameter forces the spawned process into a new process + # group which prevents the supurious SIGHUP from reaching LIT. + start_new_session=True ) body = {"processId": self.reverse_process.pid} self.send_packet( _______________________________________________ lldb-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
