fix: concurrency bug in site-replication (#14786)

The site replication status call was using a loop iteration variable sent
directly into go-routines instead of being passed as an argument. As the
variable is being updated in the loop, previously launched go routines do not
necessarily use the value at the time they were launched.

cmd/site-replication.go

@@ -40,7 +40,6 @@ import (
 	"github.com/minio/minio/internal/auth"
 	sreplication "github.com/minio/minio/internal/bucket/replication"
 	"github.com/minio/minio/internal/logger"
-	"github.com/minio/minio/internal/sync/errgroup"
 	"github.com/minio/pkg/bucket/policy"
 	bktpolicy "github.com/minio/pkg/bucket/policy"
 	iampolicy "github.com/minio/pkg/iam/policy"
@@ -2124,38 +2123,38 @@ func (c *SiteReplicationSys) SiteReplicationStatus(ctx context.Context, objAPI O
 	}
 
 	sris := make([]madmin.SRInfo, len(c.state.Peers))
-	sriErrs := make([]error, len(c.state.Peers))
+	idxMap := make(map[string]int, len(c.state.Peers))
-	g := errgroup.WithNErrs(len(c.state.Peers))
 	var depIDs []string
+	i := 0
 	for d := range c.state.Peers {
 		depIDs = append(depIDs, d)
+		idxMap[d] = i
+		i++
 	}
-	for index := range depIDs {
+
-		index := index
+	metaInfoConcErr := c.concDo(
-		if depIDs[index] == globalDeploymentID {
+		func() error {
-			g.Go(func() error {
+			srInfo, err := c.SiteReplicationMetaInfo(ctx, objAPI, opts)
-				sris[index], sriErrs[index] = c.SiteReplicationMetaInfo(ctx, objAPI, opts)
+			k := idxMap[globalDeploymentID]
-				return nil
+			sris[k] = srInfo
-			}, index)
+			return err
-			continue
+		},
-		}
+		func(deploymentID string, p madmin.PeerInfo) error {
-		g.Go(func() error {
+			admClient, err := c.getAdminClient(ctx, deploymentID)
-			admClient, err := c.getAdminClient(ctx, depIDs[index])
 			if err != nil {
 				return err
 			}
-			sris[index], sriErrs[index] = admClient.SRMetaInfo(ctx, opts)
+			srInfo, err := admClient.SRMetaInfo(ctx, opts)
-			return nil
+			k := idxMap[deploymentID]
-		}, index)
+			sris[k] = srInfo
-	}
+			return err
-	// Wait for the go routines.
+		},
-	g.Wait()
+	)
 
-	for _, serr := range sriErrs {
+	if metaInfoConcErr.summaryErr != nil {
-		if serr != nil {
+		return info, errSRBackendIssue(metaInfoConcErr.summaryErr)
-			return info, errSRBackendIssue(serr)
-		}
 	}
+
 	info.Enabled = true
 	info.Sites = make(map[string]madmin.PeerInfo, len(c.state.Peers))
 	for d, peer := range c.state.Peers {