From 2d0a0c0d297f82891faee9e3a1a286d6f20fbdd2 Mon Sep 17 00:00:00 2001 From: Paul Holzinger Date: Wed, 18 Aug 2021 20:59:37 +0200 Subject: fix rootlessport flake When the rootlessport process is started the stdout/stderr are attached to the podman process. However once everything is setup podman exits and when the rootlessport process tries to write to stdout it will fail with SIGPIPE. The code handles this signal and puts /dev/null to stdout and stderr but this is not robust. I do not understand the exact cause but sometimes the process is still killed by SIGPIPE. Either go lost the signal or the process got already killed before the goroutine could handle it. Instead of handling SIGPIPE just set /dev/null to stdout and stderr before podman exits. With this there should be no race and no way to run into SIGPIPE errors. [NO TESTS NEEDED] Fixes #11248 Signed-off-by: Paul Holzinger --- pkg/rootlessport/rootlessport_linux.go | 35 +++++++++------------------------- 1 file changed, 9 insertions(+), 26 deletions(-) (limited to 'pkg/rootlessport') diff --git a/pkg/rootlessport/rootlessport_linux.go b/pkg/rootlessport/rootlessport_linux.go index ede216bfe..9a2f93f8e 100644 --- a/pkg/rootlessport/rootlessport_linux.go +++ b/pkg/rootlessport/rootlessport_linux.go @@ -20,7 +20,6 @@ import ( "net" "os" "os/exec" - "os/signal" "path/filepath" "github.com/containernetworking/plugins/pkg/ns" @@ -106,30 +105,6 @@ func parent() error { return err } - exitC := make(chan os.Signal, 1) - defer close(exitC) - - go func() { - sigC := make(chan os.Signal, 1) - signal.Notify(sigC, unix.SIGPIPE) - defer func() { - signal.Stop(sigC) - close(sigC) - }() - - select { - case s := <-sigC: - if s == unix.SIGPIPE { - if f, err := os.OpenFile("/dev/null", os.O_WRONLY, 0755); err == nil { - unix.Dup2(int(f.Fd()), 1) // nolint:errcheck - unix.Dup2(int(f.Fd()), 2) // nolint:errcheck - f.Close() - } - } - case <-exitC: - } - }() - socketDir := filepath.Join(cfg.TmpDir, "rp") err = os.MkdirAll(socketDir, 0700) if err != nil { @@ -251,8 +226,16 @@ outer: go serve(socket, driver) } - // write and close ReadyFD (convention is same as slirp4netns --ready-fd) logrus.Info("ready") + + // https://github.com/containers/podman/issues/11248 + // Copy /dev/null to stdout and stderr to prevent SIGPIPE errors + if f, err := os.OpenFile("/dev/null", os.O_WRONLY, 0755); err == nil { + unix.Dup2(int(f.Fd()), 1) // nolint:errcheck + unix.Dup2(int(f.Fd()), 2) // nolint:errcheck + f.Close() + } + // write and close ReadyFD (convention is same as slirp4netns --ready-fd) if _, err := readyW.Write([]byte("1")); err != nil { return err } -- cgit v1.2.3-54-g00ecf