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Avoid setting stack size soft limit to Unlimited in tether #8143

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Merged
lcastellano merged 1 commit into from
Jul 18, 2018
Merged

Avoid setting stack size soft limit to Unlimited in tether #8143

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12 changes: 11 additions & 1 deletion cmd/tether/ops_linux.go
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Original file line number Diff line number Diff line change
Expand Up @@ -151,12 +151,22 @@ func ApplyDefaultULimit() {
log.Errorf("Cannot set ulimit for nofile: %s", err.Error())
}

// Setting the soft stack limit to Unlimited causes Linux to enable
// a legacy address-space-layout which is not acceptable to some
// applications. We leave the soft limit unchanged.
// Issue: https://github.com/vmware/vic/issues/8141
if err := syscall.Getrlimit(syscall.RLIMIT_STACK, &rLimit); err != nil {
log.Errorf("Cannot get ulimit for stack: %s ", err.Error())
}

// The hard limit can be safely set to Unlimited.
rLimit.Max = defaultULimit
rLimit.Cur = rLimit.Max
if err := syscall.Setrlimit(syscall.RLIMIT_STACK, &rLimit); err != nil {
log.Errorf("Cannot set ulimit for stack: %s ", err.Error())
}

rLimit.Max = defaultULimit
rLimit.Cur = rLimit.Max
if err := syscall.Setrlimit(syscall.RLIMIT_CORE, &rLimit); err != nil {
log.Errorf("Cannot set ulimit for core blocks: %s", err.Error())
}
Expand Down
32 changes: 32 additions & 0 deletions cmd/tether/ops_linux_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -20,7 +20,10 @@ import (
"errors"
"fmt"
"syscall"
"testing"

"github.com/Sirupsen/logrus"
"github.com/stretchr/testify/require"
"github.com/vishvananda/netlink"

"github.com/vmware/vic/pkg/trace"
Expand Down Expand Up @@ -159,3 +162,32 @@ func (t *Mocker) LinkBySlot(slot int32) (netlink.Link, error) {

return nil, errors.New("no such interface")
}

func TestLimitSetting(t *testing.T) {
var rLimitOut syscall.Rlimit

// CORE Limit should be set to Unlimited, MEMLOCK and NPROC, can only
// be set by root, therefore they cannot be tested here
ApplyDefaultULimit()

if err := syscall.Getrlimit(syscall.RLIMIT_CORE, &rLimitOut); err != nil {
logrus.Errorf("Cannot get ulimit for stack: %s ", err.Error())
}
require.Equal(t, rLimitOut.Max, uint64(defaultULimit))
require.Equal(t, rLimitOut.Cur, uint64(defaultULimit))

// Check the soft limit on the stack size, the new soft limit should be unchanged
// Issue: https://github.com/vmware/vic/issues/8141
if err := syscall.Getrlimit(syscall.RLIMIT_STACK, &rLimitOut); err != nil {
logrus.Errorf("Cannot get ulimit for stack: %s ", err.Error())
}
defaultSoftLimit := rLimitOut.Cur

ApplyDefaultULimit()

if err := syscall.Getrlimit(syscall.RLIMIT_STACK, &rLimitOut); err != nil {
logrus.Errorf("Cannot get ulimit for stack: %s ", err.Error())
}
require.Equal(t, rLimitOut.Max, uint64(defaultULimit))
require.Equal(t, rLimitOut.Cur, defaultSoftLimit)
}