TheArchive/tailscale
1
0
Fork 0
mirror of https://github.com/tailscale/tailscale.git synced 2025-10-16 03:14:44 +00:00
Code Issues Packages Projects Releases Wiki Activity

wgengine/magicsock: fix DERP reader hang regression during concurrent reads

Browse Source 
Fixes #1282

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
This commit is contained in:
Brad Fitzpatrick
2021-02-06 22:39:58 -08:00
committed by Brad Fitzpatrick
parent e1f773ebba
commit 6b365b0239
2 changed files with 92 additions and 37 deletions
Download Patch File Download Diff File Expand all files Collapse all files

57
wgengine/magicsock/magicsock_test.go
View File

@@ -11,7 +11,6 @@ import (
"crypto/tls"
"encoding/binary"
"encoding/json"
"flag"
"fmt"
"io/ioutil"
"net"
@@ -1435,8 +1434,6 @@ func newNonLegacyTestConn(t testing.TB) *Conn {
return conn
}
var testIssue1282 = flag.Bool("test-issue-1282", false, "run test for https://github.com/tailscale/tailscale/issues/1282 on all CPUs")
// Tests concurrent DERP readers pushing DERP data into ReceiveIPv4
// (which should blend all DERP reads into UDP reads).
func TestDerpReceiveFromIPv4(t *testing.T) {
@@ -1450,42 +1447,54 @@ func TestDerpReceiveFromIPv4(t *testing.T) {
defer sendConn.Close()
nodeKey, _ := addTestEndpoint(conn, sendConn)
var sends int = 500
senders := runtime.NumCPU()
if !*testIssue1282 {
t.Logf("--test-issue-1282 was not specified; so doing single-threaded test (instead of NumCPU=%d) to work around https://github.com/tailscale/tailscale/issues/1282", senders)
senders = 1
var sends int = 250e3 // takes about a second
if testing.Short() {
sends /= 10
}
senders := runtime.NumCPU()
sends -= (sends % senders)
var wg sync.WaitGroup
defer wg.Wait()
t.Logf("doing %v sends over %d senders", sends, senders)
ctx := context.Background()
ctx, cancel := context.WithCancel(context.Background())
defer conn.Close()
defer cancel()
doneCtx, cancelDoneCtx := context.WithCancel(context.Background())
cancelDoneCtx()
for i := 0; i < senders; i++ {
wg.Add(1)
regionID := i + 1
go func() {
defer wg.Done()
ch := make(chan bool, 1)
for i := 0; i < sends/senders; i++ {
if !conn.sendDerpReadResult(ctx, derpReadResult{
res := derpReadResult{
regionID: regionID,
n: 123,
src: key.Public(nodeKey),
copyBuf: func(dst []byte) int {
ch <- true
return 123
},
}) {
copyBuf: func(dst []byte) int { return 123 },
}
// First send with the closed context. ~50% of
// these should end up going through the
// send-a-zero-derpReadResult path, returning
// true, in which case we don't want to send again.
// We test later that we hit the other path.
if conn.sendDerpReadResult(doneCtx, res) {
continue
}
if !conn.sendDerpReadResult(ctx, res) {
t.Error("unexpected false")
return
}
<-ch
}
}()
}
zeroSendsStart := testCounterZeroDerpReadResultSend.Value()
buf := make([]byte, 1500)
for i := 0; i < sends; i++ {
n, ep, err := conn.ReceiveIPv4(buf)
@@ -1495,6 +1504,20 @@ func TestDerpReceiveFromIPv4(t *testing.T) {
_ = n
_ = ep
}
t.Logf("did %d ReceiveIPv4 calls", sends)
zeroSends, zeroRecv := testCounterZeroDerpReadResultSend.Value(), testCounterZeroDerpReadResultRecv.Value()
if zeroSends != zeroRecv {
t.Errorf("did %d zero sends != %d corresponding receives", zeroSends, zeroRecv)
}
zeroSendDelta := zeroSends - zeroSendsStart
if zeroSendDelta == 0 {
t.Errorf("didn't see any sends of derpReadResult zero value")
}
if zeroSendDelta == int64(sends) {
t.Errorf("saw %v sends of the derpReadResult zero value which was unexpectedly high (100%% of our %v sends)", zeroSendDelta, sends)
}
}
// addTestEndpoint sets conn's network map to a single peer expected