Closed
Description
What version of Go are you using (go version
)?
go version go1.10 linux/amd64
What operating system and processor architecture are you using (go env
)?
$ go env
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/psanford/.cache/go-build"
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/home/psanford/projects/go"
GORACE=""
GOROOT="/usr/local/go"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/linux_amd64"
GCCGO="gccgo"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build953969108=/tmp/go-build -gno-record-gcc-switches"
What did you do?
After upgrading to 1.10 we had one test that started to hang intermittently. The test in question starts a child process which it kills by canceling a context object at the end of the test method. It does not do an explicit cmd.Wait()
.
Here is a minimal test case that demonstrates the problem:
https://play.golang.org/p/8rq41A5Khsm
I can get this to hang consistently by running it in a bash while loop:
$ while true; do go test -timeout 5s -v -count 1 .; sleep 0.1; done
=== RUN TestOSExecNoWait
start
done
--- PASS: TestOSExecNoWait (0.01s)
PASS
ok _/tmp 0.012s
=== RUN TestOSExecNoWait
start
done
--- PASS: TestOSExecNoWait (0.01s)
PASS
ok _/tmp 0.012s
=== RUN TestOSExecNoWait
start
done
--- PASS: TestOSExecNoWait (0.01s)
PASS
ok _/tmp 0.012s
=== RUN TestOSExecNoWait
start
done
--- PASS: TestOSExecNoWait (0.01s)
PASS
<hangs here indefinitely>
If I explicitly call cmd.Wait()
the test does not hang. If I don't attach the child process' Stdout and Stderr to os.Std{out,err} the test does not hang.
On 1.9.4 the test does not hang.
Its also interesting that even though I specified -timeout 5s
the test runner hangs forever.