diff options
author | Austin Clements <austin@google.com> | 2016-01-13 15:14:26 -0500 |
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committer | Austin Clements <austin@google.com> | 2016-01-14 03:47:49 +0000 |
commit | 8319c578906249ce0871a485acb2334a6cf54d6c (patch) | |
tree | ef8446fe2959760d37a8f35eced0bfbbc5e8416c /src/runtime/futex_test.go | |
parent | 8534429181ea99c86a5ccefee508f573ae6d4ba2 (diff) | |
download | go-8319c578906249ce0871a485acb2334a6cf54d6c.tar.gz go-8319c578906249ce0871a485acb2334a6cf54d6c.zip |
runtime: fix several issues in TestFutexsleep
TestFutexsleep is supposed to clean up before returning by waking up
the goroutines it started and left blocked in futex sleeps. However,
it currently fails at this in several ways:
1. Both the sleep and wakeup are done on the address of tt.mtx, but in
both cases tt is a *local copy* of the futexsleepTest created by a
loop, so the sleep and wakeup happen on completely different
addresses. Fix this by making them both use the address of the
global tt.mtx.
2. If the sleep happens after the wakeup (not likely, but not
impossible), it won't wake up. Fix this by using the futex protocol
properly: sleep if the mutex's value is 0, and set the mutex's
value to non-zero before doing the wakeup.
3. If TestFutexsleep runs more than once, channels and mutex values
left over from the first run will interfere with later runs. Fix
this by clearing the mutex value and creating a new channel for
each test and waiting for goroutines to finish before returning
(lest they send their completion to the channel for the next run).
As an added bonus, this test now actually tests that futex
sleep/wakeup work. Previously this test would have been satisfied if
futexsleep was an infinite loop and futexwakeup was a no-op.
Change-Id: I1cbc6871cc9dcb8f4601b3621913bec2b79b0fc3
Reviewed-on: https://go-review.googlesource.com/18617
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Mikio Hara <mikioh.mikioh@gmail.com>
Diffstat (limited to 'src/runtime/futex_test.go')
-rw-r--r-- | src/runtime/futex_test.go | 25 |
1 files changed, 18 insertions, 7 deletions
diff --git a/src/runtime/futex_test.go b/src/runtime/futex_test.go index b85249a548..8504396e1a 100644 --- a/src/runtime/futex_test.go +++ b/src/runtime/futex_test.go @@ -13,6 +13,8 @@ package runtime_test import ( "runtime" + "sync" + "sync/atomic" "testing" "time" ) @@ -21,12 +23,12 @@ type futexsleepTest struct { mtx uint32 ns int64 msg string - ch chan futexsleepTest + ch chan *futexsleepTest } var futexsleepTests = []futexsleepTest{ - beforeY2038: {mtx: 0, ns: 86400 * 1e9, msg: "before the year 2038", ch: make(chan futexsleepTest, 1)}, - afterY2038: {mtx: 0, ns: (1<<31 + 100) * 1e9, msg: "after the year 2038", ch: make(chan futexsleepTest, 1)}, + beforeY2038: {mtx: 0, ns: 86400 * 1e9, msg: "before the year 2038"}, + afterY2038: {mtx: 0, ns: (1<<31 + 100) * 1e9, msg: "after the year 2038"}, } const ( @@ -42,12 +44,18 @@ func TestFutexsleep(t *testing.T) { } start := time.Now() - for _, tt := range futexsleepTests { - go func(tt futexsleepTest) { + var wg sync.WaitGroup + for i := range futexsleepTests { + tt := &futexsleepTests[i] + tt.mtx = 0 + tt.ch = make(chan *futexsleepTest, 1) + wg.Add(1) + go func(tt *futexsleepTest) { runtime.Entersyscall(0) - runtime.Futexsleep(&tt.mtx, tt.mtx, tt.ns) + runtime.Futexsleep(&tt.mtx, 0, tt.ns) runtime.Exitsyscall(0) tt.ch <- tt + wg.Done() }(tt) } loop: @@ -71,7 +79,10 @@ loop: break loop } } - for _, tt := range futexsleepTests { + for i := range futexsleepTests { + tt := &futexsleepTests[i] + atomic.StoreUint32(&tt.mtx, 1) runtime.Futexwakeup(&tt.mtx, 1) } + wg.Wait() } |