From 94ff4bc4aaad8bcd3a4eaf0e536610bed1b87833 Mon Sep 17 00:00:00 2001
From: "mingjun.zhou" <mingjun.zhou@guasemi.com>
Date: Fri, 20 Sep 2024 13:54:19 +0800
Subject: [PATCH] Fix unresovled kernel symbols when /proc/kallsyms is not
 sorted

---
 ebpf/symtab/kallsyms.go      | 5 +++++
 ebpf/symtab/kallsyms_test.go | 4 +++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/ebpf/symtab/kallsyms.go b/ebpf/symtab/kallsyms.go
index 3601dafa96..722c1acc28 100644
--- a/ebpf/symtab/kallsyms.go
+++ b/ebpf/symtab/kallsyms.go
@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"os"
 	"runtime"
+	"sort"
 	"strconv"
 )
 
@@ -94,5 +95,9 @@ func NewKallsymsFromData(kallsyms []byte) (*SymbolTab, error) {
 	if allZeros {
 		return NewSymbolTab(nil), nil
 	}
+	// kallsyms maybe unsorted when bpf/modules are loaded from userspace after kernel boot.
+	sort.Slice(syms, func(i, j int) bool {
+		return syms[i].Start < syms[j].Start
+	})
 	return NewSymbolTab(syms), nil
 }
diff --git a/ebpf/symtab/kallsyms_test.go b/ebpf/symtab/kallsyms_test.go
index fbb34bb3ae..155f409563 100644
--- a/ebpf/symtab/kallsyms_test.go
+++ b/ebpf/symtab/kallsyms_test.go
@@ -25,7 +25,9 @@ ffffffff81001750 T memblock_find
 ffffffff81001780 T __memblock_alloc_base
 ffffffff810017d0 T memblock_alloc
 ffffffff81001820 T early_memtest
-ffffffff810018a0 T early_memtest_report`
+ffffffff810018a0 T early_memtest_report
+ffffffff81000800 T unordered_symbol_0
+ffffffff81000100 T unordered_symbol_1`
 
 func TestKallsyms(t *testing.T) {
 	kallsyms, err := NewKallsymsFromData([]byte(testdata))