Merge pull request #78 from parca-dev/fix-docker-warn

fix docker warn

Author: gnurizen

interpreter/golabels/golabels.go

@@ -60,7 +60,7 @@ func Loader(_ interpreter.EbpfHandler, info *interpreter.LoaderInfo) (interprete
 	log.Debugf("file %s detected as go version %s", info.FileName(), goVersion)
 
 	offsets := getOffsets(goVersion)
-	tlsOffset, err := extractTLSGOffset(file)
+	tlsOffset, err := extractTLSGOffset(file, info.FileName())
 	if err != nil {
 		return nil, fmt.Errorf("failed to extract TLS offset: %w", err)
 	}

interpreter/golabels/tls_amd64.go

@@ -15,7 +15,7 @@ import (
 // storing the current g but "static" binaries it ends up as -80. There
 // may be dynamic relocating going on so just read it from a known
 // symbol if possible.
-func extractTLSGOffset(f *pfelf.File) (int32, error) {
+func extractTLSGOffset(f *pfelf.File, path string) (int32, error) {
 	syms, err := f.ReadSymbols()
 	if err != nil {
 		return 0, err
@@ -25,10 +25,10 @@ func extractTLSGOffset(f *pfelf.File) (int32, error) {
 	sym, err := syms.LookupSymbol("runtime.stackcheck.abi0")
 	if err != nil {
 		// Binary must be stripped, hope default is correct and warn.
-		log.Warnf("Failed to find stackcheck symbol, Go labels might not work: %v", err)
+		log.Warnf("Failed to find stackcheck symbol, Go labels might not work: %v (%s)", err, path)
 		return -8, nil
 	}
-	b, err := f.VirtualMemory(int64(sym.Address), 10, 10)
+	b, err := f.VirtualMemory(int64(sym.Address), 16, 16)
 	if err != nil {
 		return 0, err
 	}
@@ -42,7 +42,25 @@ func extractTLSGOffset(f *pfelf.File) (int32, error) {
 		if ok {
 			return int32(mem.Disp), nil
 		}
+		// allow mov const to register as well to silence warnings on this:
+		// 00000000002ed100 <runtime.stackcheck.abi0>:
+		// 2ed100: 48 c7 c1 f8 ff ff ff          movq    $-0x8, %rcx
+		// 2ed107: 64 48 8b 01                   movq    %fs:(%rcx), %rax
+		if imm, ok := i.Args[1].(x86asm.Imm); ok {
+			if reg, ok := i.Args[0].(x86asm.Reg); ok {
+				i, err = x86asm.Decode(b[i.Len:], 64)
+				if err != nil {
+					goto exit
+				}
+				if i.Op == x86asm.MOV {
+					if m, ok := i.Args[1].(x86asm.Mem); ok && m.Base == reg {
+						return int32(imm), nil
+					}
+				}
+			}
+		}
 	}
-	log.Warnf("Failed to decode stackcheck symbol, Go label collection might not work")
+exit:
+	log.Warnf("Failed to decode stackcheck symbol, Go label collection might not work %s", path)
 	return -8, nil
 }

interpreter/golabels/tls_arm64.go

@@ -21,7 +21,7 @@ import (
 //	0x000000000007f270 <+16>:    mov     x27, #0x30                      // #48
 //	0x000000000007f274 <+20>:    ldr     x28, [x0, x27]
 //	0x000000000007f278 <+24>:    ret
-func extractTLSGOffset(f *pfelf.File) (int32, error) {
+func extractTLSGOffset(f *pfelf.File, path string) (int32, error) {
 	iscgo, err := f.IsCgoEnabled()
 	if err != nil || !iscgo {
 		return 0, err
@@ -54,6 +54,6 @@ func extractTLSGOffset(f *pfelf.File) (int32, error) {
 			}
 		}
 	}
-	log.Warnf("Failed to decode load_g symbol, Go label collection might not work with CGO frames")
+	log.Warnf("Failed to decode load_g symbol, Go label collection might not work with CGO frames (%s)", path)
 	return 0, nil
 }