Merge pull request #35467 from kolyshkin/dup-mnt
Fix "duplicate mount point" when --tmpfs /dev/shm is used
diff --git a/container/container_unix.go b/container/container_unix.go
index 7785194..28a3722 100644
--- a/container/container_unix.go
+++ b/container/container_unix.go
@@ -65,12 +65,11 @@
if _, err := os.Stat(container.ResolvConfPath); err != nil {
logrus.Warnf("ResolvConfPath set to %q, but can't stat this filename (err = %v); skipping", container.ResolvConfPath, err)
} else {
- if !container.HasMountFor("/etc/resolv.conf") {
- label.Relabel(container.ResolvConfPath, container.MountLabel, shared)
- }
writable := !container.HostConfig.ReadonlyRootfs
if m, exists := container.MountPoints["/etc/resolv.conf"]; exists {
writable = m.RW
+ } else {
+ label.Relabel(container.ResolvConfPath, container.MountLabel, shared)
}
mounts = append(mounts, Mount{
Source: container.ResolvConfPath,
@@ -84,12 +83,11 @@
if _, err := os.Stat(container.HostnamePath); err != nil {
logrus.Warnf("HostnamePath set to %q, but can't stat this filename (err = %v); skipping", container.HostnamePath, err)
} else {
- if !container.HasMountFor("/etc/hostname") {
- label.Relabel(container.HostnamePath, container.MountLabel, shared)
- }
writable := !container.HostConfig.ReadonlyRootfs
if m, exists := container.MountPoints["/etc/hostname"]; exists {
writable = m.RW
+ } else {
+ label.Relabel(container.HostnamePath, container.MountLabel, shared)
}
mounts = append(mounts, Mount{
Source: container.HostnamePath,
@@ -103,12 +101,11 @@
if _, err := os.Stat(container.HostsPath); err != nil {
logrus.Warnf("HostsPath set to %q, but can't stat this filename (err = %v); skipping", container.HostsPath, err)
} else {
- if !container.HasMountFor("/etc/hosts") {
- label.Relabel(container.HostsPath, container.MountLabel, shared)
- }
writable := !container.HostConfig.ReadonlyRootfs
if m, exists := container.MountPoints["/etc/hosts"]; exists {
writable = m.RW
+ } else {
+ label.Relabel(container.HostsPath, container.MountLabel, shared)
}
mounts = append(mounts, Mount{
Source: container.HostsPath,
@@ -160,7 +157,18 @@
// HasMountFor checks if path is a mountpoint
func (container *Container) HasMountFor(path string) bool {
_, exists := container.MountPoints[path]
- return exists
+ if exists {
+ return true
+ }
+
+ // Also search among the tmpfs mounts
+ for dest := range container.HostConfig.Tmpfs {
+ if dest == path {
+ return true
+ }
+ }
+
+ return false
}
// UnmountIpcMount uses the provided unmount function to unmount shm if it was mounted
diff --git a/daemon/oci_linux_test.go b/daemon/oci_linux_test.go
new file mode 100644
index 0000000..f2f455f
--- /dev/null
+++ b/daemon/oci_linux_test.go
@@ -0,0 +1,50 @@
+package daemon
+
+import (
+ "testing"
+
+ containertypes "github.com/docker/docker/api/types/container"
+ "github.com/docker/docker/container"
+ "github.com/docker/docker/daemon/config"
+ "github.com/docker/docker/oci"
+ "github.com/docker/docker/pkg/idtools"
+
+ "github.com/stretchr/testify/assert"
+)
+
+// TestTmpfsDevShmNoDupMount checks that a user-specified /dev/shm tmpfs
+// mount (as in "docker run --tmpfs /dev/shm:rw,size=NNN") does not result
+// in "Duplicate mount point" error from the engine.
+// https://github.com/moby/moby/issues/35455
+func TestTmpfsDevShmNoDupMount(t *testing.T) {
+ d := Daemon{
+ // some empty structs to avoid getting a panic
+ // caused by a null pointer dereference
+ idMappings: &idtools.IDMappings{},
+ configStore: &config.Config{},
+ }
+ c := &container.Container{
+ ShmPath: "foobar", // non-empty, for c.IpcMounts() to work
+ HostConfig: &containertypes.HostConfig{
+ IpcMode: containertypes.IpcMode("shareable"), // default mode
+ // --tmpfs /dev/shm:rw,exec,size=NNN
+ Tmpfs: map[string]string{
+ "/dev/shm": "rw,exec,size=1g",
+ },
+ },
+ }
+
+ // Mimick the code flow of daemon.createSpec(), enough to reproduce the issue
+ ms, err := d.setupMounts(c)
+ assert.NoError(t, err)
+
+ ms = append(ms, c.IpcMounts()...)
+
+ tmpfsMounts, err := c.TmpfsMounts()
+ assert.NoError(t, err)
+ ms = append(ms, tmpfsMounts...)
+
+ s := oci.DefaultSpec()
+ err = setMounts(&d, &s, c, ms)
+ assert.NoError(t, err)
+}
