runtime/pprof: ignore dummy huge page mapping in /proc/self/maps

Change-Id: I72bea1450386100482b4681b20eb9a9af12c7522
Reviewed-on: https://go-review.googlesource.com/41816
Reviewed-by: Michael Matloob <matloob@golang.org>

diff --git a/src/runtime/pprof/proto.go b/src/runtime/pprof/proto.go
index 911565594106d86888b69f09d47b1ee10f9ec76a..5a14dab1972ae74188c7caafbb1437e40ab8a75a 100644 (file)
--- a/src/runtime/pprof/proto.go
+++ b/src/runtime/pprof/proto.go
@@ -442,12 +442,19 @@ func parseProcSelfMaps(data []byte, addMapping func(lo, hi, offset uint64, file,
                if err != nil {
                        continue
                }
-               next() // dev
-               next() // inode
+               next()          // dev
+               inode := next() // inode
                if line == nil {
                        continue
                }
                file := string(line)
+               if len(inode) == 1 && inode[0] == '0' && file == "" {
+                       // Huge-page text mappings list the initial fragment of
+                       // mapped but unpopulated memory as being inode 0.
+                       // Don't report that part.
+                       // But [vdso] and [vsyscall] are inode 0, so let non-empty file names through.
+                       continue
+               }
 
                // TODO: pprof's remapMappingIDs makes two adjustments:
                // 1. If there is an /anon_hugepage mapping first and it is

diff --git a/src/runtime/pprof/proto_test.go b/src/runtime/pprof/proto_test.go
index 53aff97798d893f1362ed84810f3989e7a4449e1..dab929c8c3c91781bc840b8feefa5d53a2fb6892 100644 (file)
--- a/src/runtime/pprof/proto_test.go
+++ b/src/runtime/pprof/proto_test.go
@@ -191,6 +191,14 @@ ffffffffff600000-ffffffffff601000 r-xp 00000090 00:00 0                  [vsysca
 7f7d77d41000 7f7d77d64000 00000000 /lib/x86_64-linux-gnu/ld-2.19.so
 7ffc34343000 7ffc34345000 00000000 [vdso]
 ffffffffff600000 ffffffffff601000 00000090 [vsyscall]
+
+00400000-07000000 r-xp 00000000 00:00 0 
+07000000-07093000 r-xp 06c00000 00:2e 536754                             /path/to/gobench_server_main
+07093000-0722d000 rw-p 06c92000 00:2e 536754                             /path/to/gobench_server_main
+0722d000-07b21000 rw-p 00000000 00:00 0 
+c000000000-c000036000 rw-p 00000000 00:00 0 
+->
+07000000 07093000 06c00000 /path/to/gobench_server_main
 `
 
 func TestProcSelfMaps(t *testing.T) {
@@ -200,12 +208,15 @@ func TestProcSelfMaps(t *testing.T) {
                        t.Fatal("malformed test case")
                }
                in, out := tt[:i], tt[i+len("->\n"):]
+               if len(out) > 0 && out[len(out)-1] != '\n' {
+                       out += "\n"
+               }
                var buf bytes.Buffer
                parseProcSelfMaps([]byte(in), func(lo, hi, offset uint64, file, buildID string) {
                        fmt.Fprintf(&buf, "%08x %08x %08x %s\n", lo, hi, offset, file)
                })
                if buf.String() != out {
-                       t.Errorf("#%d: have:\n%s\nwant:\n%s", tx, buf.String(), out)
+                       t.Errorf("#%d: have:\n%s\nwant:\n%s\n%q\n%q", tx, buf.String(), out, buf.String(), out)
                }
        }
 }