From cc2e67416692bb2a07703248a141c3913ff9811b Mon Sep 17 00:00:00 2001
From: Yu Zhou <66656208+zzz-yu@users.noreply.github.com>
Date: Tue, 15 Sep 2026 12:23:51 +0800
Subject: [PATCH] cgroup1: skip unknown blkio device rows

Ignore (unknown) blkio rows so valid device statistics continue to parse.

Signed-off-by: Yu Zhou <66656208+zzz-yu@users.noreply.github.com>
---
 cgroup1/blkio.go | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/cgroup1/blkio.go b/cgroup1/blkio.go
index 3be884c7..9c672d36 100644
--- a/cgroup1/blkio.go
+++ b/cgroup1/blkio.go
@@ -191,6 +191,10 @@ func (b *blkioController) readEntry(devices map[deviceKey]string, path, name str
 				return fmt.Errorf("invalid line found while parsing %s: %s", path, sc.Text())
 			}
 		}
+		// Kernels using NVMe multipath can report hidden devices as unknown; ignore those rows.
+		if fields[0] == "(unknown)" {
+			continue
+		}
 		major, err := strconv.ParseUint(fields[0], 10, 64)
 		if err != nil {
 			return err