From ea80f3c5a272fae0ffe3edf898f5d8f28f9160fc Mon Sep 17 00:00:00 2001
From: henrygd <hank@henrygd.me>
Date: Tue, 7 Apr 2026 18:41:22 -0400
Subject: [PATCH] fix(agent): add safety check for read returning negative
 bytes (#1799)

---
 agent/gpu_amd_linux.go | 1 +
 agent/utils/utils.go   | 4 ++++
 2 files changed, 5 insertions(+)

diff --git a/agent/gpu_amd_linux.go b/agent/gpu_amd_linux.go
index 6af0784c..a6b24973 100644
--- a/agent/gpu_amd_linux.go
+++ b/agent/gpu_amd_linux.go
@@ -156,6 +156,7 @@ func (gm *GPUManager) updateAmdGpuData(cardPath string) bool {
 func readSysfsFloat(path string) (float64, error) {
 	val, err := utils.ReadStringFileLimited(path, 64)
 	if err != nil {
+		slog.Debug("Failed to read sysfs value", "path", path, "error", err)
 		return 0, err
 	}
 	return strconv.ParseFloat(val, 64)
diff --git a/agent/utils/utils.go b/agent/utils/utils.go
index 1e682b1e..b8e8d993 100644
--- a/agent/utils/utils.go
+++ b/agent/utils/utils.go
@@ -1,6 +1,7 @@
 package utils
 
 import (
+	"fmt"
 	"io"
 	"math"
 	"os"
@@ -68,6 +69,9 @@ func ReadStringFileLimited(path string, maxSize int) (string, error) {
 	if err != nil && err != io.EOF {
 		return "", err
 	}
+	if n < 0 {
+		return "", fmt.Errorf("%s returned negative bytes: %d", path, n)
+	}
 	return strings.TrimSpace(string(buf[:n])), nil
 }