runtime/pprof: hide map runtime frames from heap profiles

Heap profiles hide "runtime" frames like runtime.mapassign. This broke
in 1.24 because the map implementation moved to internal/runtime/maps,
and runtime/pprof only considered literal "runtime." when looking for
runtime frames.

It would be nice to use cmd/internal/objabi.PkgSpecial to find runtime
packages, but that is hidden away in cmd.

Fixes #71174.

Change-Id: I6a6a636cb42aa17539e47da16854bd3fd8cb1bfe
Reviewed-on: https://go-review.googlesource.com/c/go/+/641775
Auto-Submit: Michael Pratt <mpratt@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>

diff --git a/src/runtime/pprof/pprof.go b/src/runtime/pprof/pprof.go
index f6b4a5c367f05fd3c4a2490927c27709018ea03a..b7680a13fdcb2589ed7a4be0fb03b26764c28c78 100644 (file)
--- a/src/runtime/pprof/pprof.go
+++ b/src/runtime/pprof/pprof.go
@@ -555,7 +555,7 @@ func printStackRecord(w io.Writer, stk []uintptr, allFrames bool) {
                if name == "" {
                        show = true
                        fmt.Fprintf(w, "#\t%#x\n", frame.PC)
-               } else if name != "runtime.goexit" && (show || !strings.HasPrefix(name, "runtime.")) {
+               } else if name != "runtime.goexit" && (show || !(strings.HasPrefix(name, "runtime.") || strings.HasPrefix(name, "internal/runtime/"))) {
                        // Hide runtime.goexit and any runtime functions at the beginning.
                        // This is useful mainly for allocation traces.
                        show = true

diff --git a/src/runtime/pprof/protomem.go b/src/runtime/pprof/protomem.go
index ab3550f43f9a390544dcf87324dec9406d7a8268..72aad82b3005343572c8be15b291720aefa904f4 100644 (file)
--- a/src/runtime/pprof/protomem.go
+++ b/src/runtime/pprof/protomem.go
@@ -36,7 +36,7 @@ func writeHeapProto(w io.Writer, p []profilerecord.MemProfileRecord, rate int64,
                        // what appendLocsForStack expects.
                        if hideRuntime {
                                for i, addr := range stk {
-                                       if f := runtime.FuncForPC(addr); f != nil && strings.HasPrefix(f.Name(), "runtime.") {
+                                       if f := runtime.FuncForPC(addr); f != nil && (strings.HasPrefix(f.Name(), "runtime.") || strings.HasPrefix(f.Name(), "internal/runtime/")) {
                                                continue
                                        }
                                        // Found non-runtime. Show any runtime uses above it.

diff --git a/src/runtime/pprof/protomem_test.go b/src/runtime/pprof/protomem_test.go
index 885f4dca5b87624814bb9577782fda766f66d43c..4d08e67ddc7540123367c35f37a631ae0c5c9dd8 100644 (file)
--- a/src/runtime/pprof/protomem_test.go
+++ b/src/runtime/pprof/protomem_test.go
@@ -118,7 +118,7 @@ func locationToStrings(loc *profile.Location, funcs []string) []string {
        return funcs
 }
 
-// This is a regression test for https://go.dev/issue/64528 .
+// This is a regression test for https://go.dev/issue/64528.
 func TestGenericsHashKeyInPprofBuilder(t *testing.T) {
        if asan.Enabled {
                t.Skip("extra allocations with -asan throw off the test; see #70079")
@@ -229,3 +229,61 @@ func TestGenericsInlineLocations(t *testing.T) {
                t.Errorf("expected a location with at least 3 functions\n%s\ngot\n%s\n", expectedLocation, actual)
        }
 }
+
+func growMap() {
+       m := make(map[int]int)
+       for i := range 512 {
+               m[i] = i
+       }
+}
+
+// Runtime frames are hidden in heap profiles.
+// This is a regression test for https://go.dev/issue/71174.
+func TestHeapRuntimeFrames(t *testing.T) {
+       previousRate := runtime.MemProfileRate
+       runtime.MemProfileRate = 1
+       defer func() {
+               runtime.MemProfileRate = previousRate
+       }()
+
+       growMap()
+
+       runtime.GC()
+       buf := bytes.NewBuffer(nil)
+       if err := WriteHeapProfile(buf); err != nil {
+               t.Fatalf("writing profile: %v", err)
+       }
+       p, err := profile.Parse(buf)
+       if err != nil {
+               t.Fatalf("profile.Parse: %v", err)
+       }
+
+       actual := profileToStrings(p)
+
+       // We must see growMap at least once.
+       foundGrowMap := false
+       for _, l := range actual {
+               if !strings.Contains(l, "runtime/pprof.growMap") {
+                       continue
+               }
+               foundGrowMap = true
+
+               // Runtime frames like mapassign and map internals should be hidden.
+               if strings.Contains(l, "runtime.") {
+                       t.Errorf("Sample got %s, want no runtime frames", l)
+               }
+               if strings.Contains(l, "internal/runtime/") {
+                       t.Errorf("Sample got %s, want no runtime frames", l)
+               }
+               if strings.Contains(l, "runtime/internal/") {
+                       t.Errorf("Sample got %s, want no runtime frames", l)
+               }
+               if strings.Contains(l, "mapassign") { // in case mapassign moves to a package not matching above paths.
+                       t.Errorf("Sample got %s, want no mapassign frames", l)
+               }
+       }
+
+       if !foundGrowMap {
+               t.Errorf("Profile got:\n%s\nwant sample in runtime/pprof.growMap", strings.Join(actual, "\n"))
+       }
+}