ITQC/containernetworking-plugins
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ns: fix reading net namespace in multi-threaded processes

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/proc/self/ns/net gives the main thread's namespace, not necessarily
the namespace of the thread that's running the testcases.  This causes
sporadic failures of the tests.

For example, with a testcase reading inodes after switching netns:

/proc/27686/task/27689/ns/net 4026532565
/proc/self/ns/net 4026531969
/proc/27686/task/27689/ns/net 4026532565

See also:
008d17ae00

Running Suite: pkg/ns Suite
===========================
Random Seed: 1459953577
Will run 6 of 6 specs

• Failure [0.028 seconds]
Linux namespace operations
/cni/gopath/src/github.com/appc/cni/pkg/ns/ns_test.go:167
  WithNetNS
  /cni/gopath/src/github.com/appc/cni/pkg/ns/ns_test.go:166
    executes the callback within the target network namespace [It]
    /cni/gopath/src/github.com/appc/cni/pkg/ns/ns_test.go:97

    Expected
        <uint64>: 4026531969
    to equal
        <uint64>: 4026532565

    /cni/gopath/src/github.com/appc/cni/pkg/ns/ns_test.go:96
------------------------------
•••••

Summarizing 1 Failure:

[Fail] Linux namespace operations WithNetNS [It] executes the callback within the target network namespace
/cni/gopath/src/github.com/appc/cni/pkg/ns/ns_test.go:96

Ran 6 of 6 Specs in 0.564 seconds
FAIL! -- 5 Passed | 1 Failed | 0 Pending | 0 Skipped --- FAIL: TestNs (0.56s)
FAIL
This commit is contained in:
Dan Williams 2016-04-06 11:03:31 -05:00
parent c085ec98fd
commit c272c49555
2 changed files with 18 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
ns/ns_test.go
View File

@ -28,13 +28,9 @@ import (
. "github.com/onsi/gomega"
)
const CurrentNetNS = "/proc/self/ns/net"
var _ = Describe("Linux namespace operations", func() {
Describe("WithNetNS", func() {
var (
originalNetNS *os.File
targetNetNSName string
targetNetNSPath string
targetNetNS *os.File
@ -42,8 +38,6 @@ var _ = Describe("Linux namespace operations", func() {
BeforeEach(func() {
var err error
originalNetNS, err = os.Open(CurrentNetNS)
Expect(err).NotTo(HaveOccurred())
targetNetNSName = fmt.Sprintf("test-netns-%d", rand.Int())
@ -60,8 +54,6 @@ var _ = Describe("Linux namespace operations", func() {
err := exec.Command("ip", "netns", "del", targetNetNSName).Run()
Expect(err).NotTo(HaveOccurred())
Expect(originalNetNS.Close()).To(Succeed())
})
It("executes the callback within the target network namespace", func() {
@ -71,7 +63,7 @@ var _ = Describe("Linux namespace operations", func() {
var actualInode uint64
var innerErr error
err = ns.WithNetNS(targetNetNS, false, func(*os.File) error {
actualInode, innerErr = testhelpers.GetInode(CurrentNetNS)
actualInode, innerErr = testhelpers.GetInodeCurNetNS()
return nil
})
Expect(err).NotTo(HaveOccurred())
@ -81,7 +73,7 @@ var _ = Describe("Linux namespace operations", func() {
})
It("provides the original namespace as the argument to the callback", func() {
hostNSInode, err := testhelpers.GetInode(CurrentNetNS)
hostNSInode, err := testhelpers.GetInodeCurNetNS()
Expect(err).NotTo(HaveOccurred())
var inputNSInode uint64
@ -97,7 +89,7 @@ var _ = Describe("Linux namespace operations", func() {
})
It("restores the calling thread to the original network namespace", func() {
preTestInode, err := testhelpers.GetInode(CurrentNetNS)
preTestInode, err := testhelpers.GetInodeCurNetNS()
Expect(err).NotTo(HaveOccurred())
err = ns.WithNetNS(targetNetNS, false, func(*os.File) error {
@ -105,7 +97,7 @@ var _ = Describe("Linux namespace operations", func() {
})
Expect(err).NotTo(HaveOccurred())
postTestInode, err := testhelpers.GetInode(CurrentNetNS)
postTestInode, err := testhelpers.GetInodeCurNetNS()
Expect(err).NotTo(HaveOccurred())
Expect(postTestInode).To(Equal(preTestInode))
@ -113,14 +105,14 @@ var _ = Describe("Linux namespace operations", func() {
Context("when the callback returns an error", func() {
It("restores the calling thread to the original namespace before returning", func() {
preTestInode, err := testhelpers.GetInode(CurrentNetNS)
preTestInode, err := testhelpers.GetInodeCurNetNS()
Expect(err).NotTo(HaveOccurred())
_ = ns.WithNetNS(targetNetNS, false, func(*os.File) error {
return errors.New("potato")
})
postTestInode, err := testhelpers.GetInode(CurrentNetNS)
postTestInode, err := testhelpers.GetInodeCurNetNS()
Expect(err).NotTo(HaveOccurred())
Expect(postTestInode).To(Equal(preTestInode))
@ -136,7 +128,7 @@ var _ = Describe("Linux namespace operations", func() {
Describe("validating inode mapping to namespaces", func() {
It("checks that different namespaces have different inodes", func() {
hostNSInode, err := testhelpers.GetInode(CurrentNetNS)
hostNSInode, err := testhelpers.GetInodeCurNetNS()
Expect(err).NotTo(HaveOccurred())
testNsInode, err := testhelpers.GetInode(targetNetNSPath)

14
testhelpers/testhelpers.go
View File

@ -27,6 +27,16 @@ import (
. "github.com/onsi/gomega"
)
func getCurrentThreadNetNSPath() string {
pid := unix.Getpid()
tid := unix.Gettid()
return fmt.Sprintf("/proc/%d/task/%d/ns/net", pid, tid)
}
func GetInodeCurNetNS() (uint64, error) {
return GetInode(getCurrentThreadNetNSPath())
}
func GetInode(path string) (uint64, error) {
file, err := os.Open(path)
if err != nil {
@ -68,9 +78,7 @@ func MakeNetworkNS(containerID string) string {
defer GinkgoRecover()
// capture current thread's original netns
pid := unix.Getpid()
tid := unix.Gettid()
currentThreadNetNSPath := fmt.Sprintf("/proc/%d/task/%d/ns/net", pid, tid)
currentThreadNetNSPath := getCurrentThreadNetNSPath()
originalNetNS, err := unix.Open(currentThreadNetNSPath, unix.O_RDONLY, 0)
Expect(err).NotTo(HaveOccurred())
defer unix.Close(originalNetNS)