chore: invoke rlimit.RemoveMemLock only once in main thread (#686)

# Description

We only need to invoke `rlimit.RemoveMemLock` once, no need to do it in
every plugin
## Related Issue

If this pull request is related to any issue, please mention it here.
Additionally, make sure that the issue is assigned to you before
submitting this pull request.

## Checklist

- [ ] I have read the [contributing
documentation](https://retina.sh/docs/contributing).
- [ ] I signed and signed-off the commits (`git commit -S -s ...`). See
[this
documentation](https://docs.github.com/en/authentication/managing-commit-signature-verification/about-commit-signature-verification)
on signing commits.
- [ ] I have correctly attributed the author(s) of the code.
- [ ] I have tested the changes locally.
- [ ] I have followed the project's style guidelines.
- [ ] I have updated the documentation, if necessary.
- [ ] I have added tests, if applicable.

## Screenshots (if applicable) or Testing Completed

All plugins are still able to initialize and run normally.
## Additional Notes

Add any additional notes or context about the pull request here.

---

Please refer to the [CONTRIBUTING.md](../CONTRIBUTING.md) file for more
information on how to contribute to this project.

cmd/hubble/daemon_main_linux.go

@@ -31,6 +31,7 @@ import (
 	"github.com/cilium/cilium/pkg/option"
 	"github.com/cilium/cilium/pkg/promise"
 	"github.com/cilium/cilium/pkg/time"
+	"github.com/cilium/ebpf/rlimit"
 	"github.com/cilium/proxy/pkg/logging"
 	"github.com/microsoft/retina/internal/buildinfo"
 	"github.com/microsoft/retina/pkg/config"
@@ -300,6 +301,11 @@ func Execute(cobraCmd *cobra.Command, h *hive.Hive) {
 	initDaemonConfig(h.Viper())
 	initLogging()
 
+	// Allow the current process to lock memory for eBPF resources.
+	if err := rlimit.RemoveMemlock(); err != nil {
+		logger.Fatal("failed to remove memlock", zap.Error(err))
+	}
+
 	//nolint:gocritic // without granular commits this commented-out code may be lost
 	// initEnv(h.Viper())
 

cmd/legacy/daemon.go

@@ -25,6 +25,7 @@ import (
 	crmgr "sigs.k8s.io/controller-runtime/pkg/manager"
 	metricsserver "sigs.k8s.io/controller-runtime/pkg/metrics/server"
 
+	"github.com/cilium/ebpf/rlimit"
 	"github.com/go-logr/zapr"
 	retinav1alpha1 "github.com/microsoft/retina/crd/api/v1alpha1"
 	"github.com/microsoft/retina/internal/buildinfo"
@@ -132,6 +133,11 @@ func (d *Daemon) Start() error {
 	defer zl.Close()
 	mainLogger := zl.Named("main").Sugar()
 
+	// Allow the current process to lock memory for eBPF resources.
+	if err = rlimit.RemoveMemlock(); err != nil {
+		mainLogger.Fatal("failed to remove memlock", zap.Error(err))
+	}
+
 	metrics.InitializeMetrics()
 
 	mainLogger.Info(zap.String("data aggregation level", daemonConfig.DataAggregationLevel.String()))

pkg/plugin/conntrack/conntrack_linux.go

@@ -9,7 +9,6 @@ import (
 	"time"
 
 	"github.com/cilium/ebpf"
-	"github.com/cilium/ebpf/rlimit"
 	"github.com/microsoft/retina/internal/ktime"
 	"github.com/microsoft/retina/pkg/config"
 	"github.com/microsoft/retina/pkg/log"
@@ -37,11 +36,6 @@ func (ct *Conntrack) Run(ctx context.Context) error {
 		ct.l.Info("conntrack is disabled in low data aggregation level")
 		return nil
 	}
-	// Allow the current process to lock memory for eBPF resources.
-	if err := rlimit.RemoveMemlock(); err != nil {
-		ct.l.Error("RemoveMemlock failed", zap.Error(err))
-		return errors.Wrapf(err, "failed to remove memlock limit")
-	}
 
 	objs := &conntrackObjects{}
 	err := loadConntrackObjects(objs, &ebpf.CollectionOptions{

pkg/plugin/dns/dns_linux.go

@@ -12,7 +12,6 @@ import (
 	"strings"
 
 	v1 "github.com/cilium/cilium/pkg/hubble/api/v1"
-	"github.com/cilium/ebpf/rlimit"
 	"github.com/inspektor-gadget/inspektor-gadget/pkg/gadgets/trace/dns/tracer"
 	"github.com/inspektor-gadget/inspektor-gadget/pkg/gadgets/trace/dns/types"
 	"github.com/inspektor-gadget/inspektor-gadget/pkg/utils/host"
@@ -46,11 +45,6 @@ func (d *dns) Compile(ctx context.Context) error {
 }
 
 func (d *dns) Init() error {
-	if err := rlimit.RemoveMemlock(); err != nil {
-		d.l.Error("RemoveMemLock failed:%w", zap.Error(err))
-		return err
-	}
-
 	// Create tracer. In this case no parameters are passed.
 	err := host.Init(host.Config{})
 	tracer, err := tracer.NewTracer()

pkg/plugin/dropreason/dropreason_linux.go

@@ -20,7 +20,6 @@ import (
 	"github.com/cilium/ebpf"
 	"github.com/cilium/ebpf/link"
 	"github.com/cilium/ebpf/perf"
-	"github.com/cilium/ebpf/rlimit"
 	"github.com/microsoft/retina/internal/ktime"
 	kcfg "github.com/microsoft/retina/pkg/config"
 	"github.com/microsoft/retina/pkg/enricher"
@@ -118,12 +117,6 @@ func (dr *dropReason) Compile(ctx context.Context) error {
 
 func (dr *dropReason) Init() error {
 	var err error
-
-	if err = rlimit.RemoveMemlock(); err != nil {
-		dr.l.Error("RemoveMemLock failed:%w", zap.Error(err))
-		return err
-	}
-
 	// Get the absolute path to this file during runtime.
 	dir, err := absPath()
 	if err != nil {

pkg/plugin/packetforward/packetforward_linux.go

@@ -18,7 +18,6 @@ import (
 
 	hubblev1 "github.com/cilium/cilium/pkg/hubble/api/v1"
 	"github.com/cilium/ebpf"
-	"github.com/cilium/ebpf/rlimit"
 	"github.com/microsoft/retina/pkg/loader"
 	"github.com/microsoft/retina/pkg/log"
 	"github.com/microsoft/retina/pkg/metrics"
@@ -132,11 +131,6 @@ func (p *packetForward) Compile(ctx context.Context) error {
 }
 
 func (p *packetForward) Init() error {
-	if err := rlimit.RemoveMemlock(); err != nil {
-		p.l.Error("RemoveMemLock failed:%w", zap.Error(err))
-		return err
-	}
-
 	// Get the absolute path to this file during runtime.
 	dir, err := absPath()
 	if err != nil {

pkg/plugin/packetparser/packetparser_linux.go

@@ -20,7 +20,6 @@ import (
 	v1 "github.com/cilium/cilium/pkg/hubble/api/v1"
 	"github.com/cilium/ebpf"
 	"github.com/cilium/ebpf/perf"
-	"github.com/cilium/ebpf/rlimit"
 	"github.com/florianl/go-tc"
 	helper "github.com/florianl/go-tc/core"
 	"github.com/microsoft/retina/internal/ktime"
@@ -118,12 +117,6 @@ func (p *packetParser) Init() error {
 		p.l.Warn("packet parser and latency plugin will not init because pod level is disabled")
 		return nil
 	}
-
-	if err := rlimit.RemoveMemlock(); err != nil {
-		p.l.Error("RemoveMemLock failed:%w", zap.Error(err))
-		return err
-	}
-
 	// Get the absolute path to this file during runtime.
 	dir, err := absPath()
 	if err != nil {

pkg/plugin/tcpretrans/tcpretrans_linux.go

@@ -11,7 +11,6 @@ import (
 	"strings"
 
 	v1 "github.com/cilium/cilium/pkg/hubble/api/v1"
-	"github.com/cilium/ebpf/rlimit"
 	gadgetcontext "github.com/inspektor-gadget/inspektor-gadget/pkg/gadget-context"
 	"github.com/inspektor-gadget/inspektor-gadget/pkg/gadgets/trace/tcpretrans/tracer"
 	"github.com/inspektor-gadget/inspektor-gadget/pkg/gadgets/trace/tcpretrans/types"
@@ -50,12 +49,6 @@ func (t *tcpretrans) Init() error {
 		t.l.Warn("tcpretrans will not init because pod level is disabled")
 		return nil
 	}
-
-	if err := rlimit.RemoveMemlock(); err != nil {
-		t.l.Error("RemoveMemLock failed", zap.Error(err))
-		return err
-	}
-
 	// Create tracer. In this case no parameters are passed.
 	if err := host.Init(host.Config{}); err != nil {
 		t.l.Error("failed to init host", zap.Error(err))