From 7664338d24e01d8b47da1b0b8fac6ad9f097e572 Mon Sep 17 00:00:00 2001
From: Rafael Roquetto <rafaelroquetto@users.noreply.github.com>
Date: Sat, 21 Dec 2024 15:42:55 -0600
Subject: [PATCH] Treat go binaries without offsets as generic (#1476)

---
 pkg/internal/discover/attacher.go    |  4 +++-
 pkg/internal/discover/typer.go       | 17 +++++++++++++++--
 pkg/internal/goexec/structmembers.go |  2 +-
 3 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/pkg/internal/discover/attacher.go b/pkg/internal/discover/attacher.go
index 23fc892fd..b6d8632d0 100644
--- a/pkg/internal/discover/attacher.go
+++ b/pkg/internal/discover/attacher.go
@@ -134,9 +134,11 @@ func (ta *TraceAttacher) getTracer(ie *ebpf.Instrumentable) bool {
 	case svc.InstrumentableGolang:
 		// gets all the possible supported tracers for a go program, and filters out
 		// those whose symbols are not present in the ELF functions list
-		if ta.Cfg.Discovery.SkipGoSpecificTracers || ta.Cfg.Discovery.SystemWide || ie.InstrumentationError != nil {
+		if ta.Cfg.Discovery.SkipGoSpecificTracers || ta.Cfg.Discovery.SystemWide || ie.InstrumentationError != nil || ie.Offsets == nil {
 			if ie.InstrumentationError != nil {
 				ta.log.Warn("Unsupported Go program detected, using generic instrumentation", "error", ie.InstrumentationError)
+			} else if ie.Offsets == nil {
+				ta.log.Warn("Go program with null offsets detected, using generic instrumentation")
 			}
 			if ta.reusableTracer != nil {
 				// We need to do more than monitor PIDs. It's possible that this new
diff --git a/pkg/internal/discover/typer.go b/pkg/internal/discover/typer.go
index 00b23c7b4..8215b6709 100644
--- a/pkg/internal/discover/typer.go
+++ b/pkg/internal/discover/typer.go
@@ -1,6 +1,7 @@
 package discover
 
 import (
+	"fmt"
 	"log/slog"
 	"strings"
 
@@ -124,6 +125,11 @@ func (t *typer) asInstrumentable(execElf *exec.FileInfo) ebpf.Instrumentable {
 			instrumentableCache.Add(execElf.Ino, InstrumentedExecutable{Type: svc.InstrumentableGolang, Offsets: offsets})
 			return ebpf.Instrumentable{Type: svc.InstrumentableGolang, FileInfo: execElf, Offsets: offsets}
 		}
+
+		if err == nil {
+			err = fmt.Errorf("identified as a Go proxy")
+		}
+
 		log.Debug("identified as a Go proxy")
 	} else {
 		log.Debug("identified as a generic, non-Go executable")
@@ -146,12 +152,19 @@ func (t *typer) asInstrumentable(execElf *exec.FileInfo) ebpf.Instrumentable {
 
 	detectedType := exec.FindProcLanguage(execElf.Pid, execElf.ELF, execElf.CmdExePath)
 
+	if detectedType == svc.InstrumentableGolang && err == nil {
+		log.Warn("ELF binary appears to be a Go program, but no offsets were found",
+			"comm", execElf.CmdExePath, "pid", execElf.Pid)
+
+		err = fmt.Errorf("could not find any Go offsets in Go binary %s", execElf.CmdExePath)
+	}
+
 	log.Debug("instrumented", "comm", execElf.CmdExePath, "pid", execElf.Pid,
 		"child", child, "language", detectedType.String())
 	// Return the instrumentable without offsets, as it is identified as a generic
 	// (or non-instrumentable Go proxy) executable
-	instrumentableCache.Add(execElf.Ino, InstrumentedExecutable{Type: detectedType, Offsets: offsets, InstrumentationError: err})
-	return ebpf.Instrumentable{Type: detectedType, FileInfo: execElf, ChildPids: child, InstrumentationError: err}
+	instrumentableCache.Add(execElf.Ino, InstrumentedExecutable{Type: detectedType, Offsets: nil, InstrumentationError: err})
+	return ebpf.Instrumentable{Type: detectedType, Offsets: nil, FileInfo: execElf, ChildPids: child, InstrumentationError: err}
 }
 
 func (t *typer) inspectOffsets(execElf *exec.FileInfo) (*goexec.Offsets, bool, error) {
diff --git a/pkg/internal/goexec/structmembers.go b/pkg/internal/goexec/structmembers.go
index a47cd1bd8..90ea2e769 100644
--- a/pkg/internal/goexec/structmembers.go
+++ b/pkg/internal/goexec/structmembers.go
@@ -443,7 +443,7 @@ func structMemberOffsetsFromDwarf(data *dwarf.Data) (FieldOffsets, map[GoOffset]
 		log.Debug("inspecting fields for struct type", "type", typeName)
 		if err := readMembers(reader, structMember.fields, expectedReturns, fieldOffsets); err != nil {
 			log.Debug("error reading DWARF info", "type", typeName, "error", err)
-			return nil, expectedReturns
+			return fieldOffsets, expectedReturns
 		}
 	}
 }