Merge pull request #24400 from giuseppe/fix-race-reading-cgroup-stats

libpod: report cgroups deleted during Stat() call

libpod/stats_linux.go

@@ -3,6 +3,7 @@
 package libpod
 
 import (
+	"errors"
 	"fmt"
 	"strings"
 	"syscall"
@@ -36,6 +37,11 @@ func (c *Container) getPlatformContainerStats(stats *define.ContainerStats, prev
 	// Ubuntu does not have swap memory in cgroups because swap is often not enabled.
 	cgroupStats, err := cgroup.Stat()
 	if err != nil {
+		// cgroup.Stat() is not an atomic operation, so it is possible that the cgroup is removed
+		// while Stat() is running.  Try to catch this case and return a more specific error.
+		if (errors.Is(err, unix.ENOENT) || errors.Is(err, unix.ENODEV)) && !cgroupExist(cgroupPath) {
+			return fmt.Errorf("cgroup %s does not exist: %w", cgroupPath, define.ErrCtrStopped)
+		}
 		return fmt.Errorf("unable to obtain cgroup stats: %w", err)
 	}
 	conState := c.state.State