[PATCH v4] transport-helper, connect: use clean_on_exit to reap children on abnormal exit
- From
Andrew Au <cshung@gmail.com>
- Date
- Mar 12, 2026, 21:49 UTC
- Message-ID
- <20260312214945.4050010-1-cshung@gmail.com>
- In-Reply-To
- <20260311184206.GA1911377@coredump.intra.peff.net>
When a long-running service (e.g., a source indexer) runs as PID 1 inside a container and repeatedly spawns git, git may in turn spawn child processes such as git-remote-https or ssh. If git exits abnormally (e.g., via exit(128) on a transport error), the normal cleanup paths (disconnect_helper, finish_connect) are bypassed, and these children are never waited on. The children are reparented to PID 1, which does not reap them, so they accumulate as zombies over time.
Set clean_on_exit and wait_after_clean on child_process structs in both transport-helper.c and connect.c so that the existing run-command cleanup infrastructure handles reaping on any exit path. This avoids rolling custom atexit handlers that call finish_command(), which could deadlock if the child is blocked waiting for the parent to close a pipe.
The clean_on_exit mechanism sends SIGTERM first, then waits, ensuring the child terminates promptly. It also handles signal-based exits, not just atexit.
Signed-off-by: Andrew Au <cshung@gmail.com> --- connect.c | 4 ++++ transport-helper.c | 2 ++ 2 files changed, 6 insertions(+)
diff --git a/connect.c b/connect.c index eef752f14..5039adca7 100644 --- a/connect.c +++ b/connect.c @@ -989,6 +989,8 @@ static struct child_process *git_proxy_connect(int fd[2], char *host) strvec_push(&proxy->args, port); proxy->in = -1; proxy->out = -1; + proxy->clean_on_exit = 1; + proxy->wait_after_clean = 1; if (start_command(proxy)) die(_("cannot start proxy %s"), git_proxy_command); fd[0] = proxy->out; /* read from proxy stdout */ @@ -1447,6 +1449,8 @@ struct child_process *git_connect(int fd[2], const char *url, } strvec_push(&conn->args, cmd.buf); + conn->clean_on_exit = 1; + conn->wait_after_clean = 1; if (start_command(conn)) die(_("unable to fork")); diff --git a/transport-helper.c b/transport-helper.c index e95267a4a..6633a999b 100644 --- a/transport-helper.c +++ b/transport-helper.c @@ -140,6 +140,8 @@ static struct child_process *get_helper(struct transport *transport) helper->trace2_child_class = helper->args.v[0]; /* "remote-<name>" */ + helper->clean_on_exit = 1; + helper->wait_after_clean = 1; code = start_command(helper); if (code < 0 && errno == ENOENT) die(_("unable to find remote helper for '%s'"), data->name);
-- 2.43.0