runtime: fix CGO traceback frame count
Without this, each additional C frame found via SetCgoTraceback will
cause a frame to be dropped from the bottom of the traceback stack.
Fixes #29034
Change-Id: I90aa6b2a1dced90c69b64c5dd565fe64a25724a3
Reviewed-on: https://go-review.googlesource.com/c/151917
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
diff --git a/src/runtime/crash_cgo_test.go b/src/runtime/crash_cgo_test.go
index 6da8341..c1dd757 100644
--- a/src/runtime/crash_cgo_test.go
+++ b/src/runtime/crash_cgo_test.go
@@ -263,7 +263,7 @@
}
}
-func testCgoPprof(t *testing.T, buildArg, runArg string) {
+func testCgoPprof(t *testing.T, buildArg, runArg, top, bottom string) {
t.Parallel()
if runtime.GOOS != "linux" || (runtime.GOARCH != "amd64" && runtime.GOARCH != "ppc64le") {
t.Skipf("not yet supported on %s/%s", runtime.GOOS, runtime.GOARCH)
@@ -287,7 +287,7 @@
defer os.Remove(fn)
for try := 0; try < 2; try++ {
- cmd := testenv.CleanCmdEnv(exec.Command(testenv.GoToolPath(t), "tool", "pprof", "-top", "-nodecount=1"))
+ cmd := testenv.CleanCmdEnv(exec.Command(testenv.GoToolPath(t), "tool", "pprof", "-traces"))
// Check that pprof works both with and without explicit executable on command line.
if try == 0 {
cmd.Args = append(cmd.Args, exe, fn)
@@ -307,30 +307,38 @@
cmd.Env = append(cmd.Env, "PPROF_TMPDIR="+os.TempDir())
}
- top, err := cmd.CombinedOutput()
- t.Logf("%s:\n%s", cmd.Args, top)
+ out, err := cmd.CombinedOutput()
+ t.Logf("%s:\n%s", cmd.Args, out)
if err != nil {
t.Error(err)
- } else if !bytes.Contains(top, []byte("cpuHog")) {
- t.Error("missing cpuHog in pprof output")
+ continue
+ }
+
+ trace := findTrace(string(out), top)
+ if len(trace) == 0 {
+ t.Errorf("%s traceback missing.", top)
+ continue
+ }
+ if trace[len(trace)-1] != bottom {
+ t.Errorf("invalid traceback origin: got=%v; want=[%s ... %s]", trace, top, bottom)
}
}
}
func TestCgoPprof(t *testing.T) {
- testCgoPprof(t, "", "CgoPprof")
+ testCgoPprof(t, "", "CgoPprof", "cpuHog", "runtime.main")
}
func TestCgoPprofPIE(t *testing.T) {
- testCgoPprof(t, "-buildmode=pie", "CgoPprof")
+ testCgoPprof(t, "-buildmode=pie", "CgoPprof", "cpuHog", "runtime.main")
}
func TestCgoPprofThread(t *testing.T) {
- testCgoPprof(t, "", "CgoPprofThread")
+ testCgoPprof(t, "", "CgoPprofThread", "cpuHogThread", "cpuHogThread2")
}
func TestCgoPprofThreadNoTraceback(t *testing.T) {
- testCgoPprof(t, "", "CgoPprofThreadNoTraceback")
+ testCgoPprof(t, "", "CgoPprofThreadNoTraceback", "cpuHogThread", "runtime._ExternalCode")
}
func TestRaceProf(t *testing.T) {
@@ -509,3 +517,35 @@
t.Errorf("expected %q got %v", want, got)
}
}
+
+func nextTrace(lines []string) ([]string, []string) {
+ var trace []string
+ for n, line := range lines {
+ if strings.HasPrefix(line, "---") {
+ return trace, lines[n+1:]
+ }
+ fields := strings.Fields(strings.TrimSpace(line))
+ if len(fields) == 0 {
+ continue
+ }
+ // Last field contains the function name.
+ trace = append(trace, fields[len(fields)-1])
+ }
+ return nil, nil
+}
+
+func findTrace(text, top string) []string {
+ lines := strings.Split(text, "\n")
+ _, lines = nextTrace(lines) // Skip the header.
+ for len(lines) > 0 {
+ var t []string
+ t, lines = nextTrace(lines)
+ if len(t) == 0 {
+ continue
+ }
+ if t[0] == top {
+ return t
+ }
+ }
+ return nil
+}
diff --git a/src/runtime/proc.go b/src/runtime/proc.go
index 409869f..fc77a96 100644
--- a/src/runtime/proc.go
+++ b/src/runtime/proc.go
@@ -3742,6 +3742,9 @@
// Collect Go stack that leads to the cgo call.
n = gentraceback(mp.curg.syscallpc, mp.curg.syscallsp, 0, mp.curg, 0, &stk[cgoOff], len(stk)-cgoOff, nil, nil, 0)
+ if n > 0 {
+ n += cgoOff
+ }
} else if traceback {
n = gentraceback(pc, sp, lr, gp, 0, &stk[0], len(stk), nil, nil, _TraceTrap|_TraceJumpStack)
}
diff --git a/src/runtime/testdata/testprogcgo/pprof.go b/src/runtime/testdata/testprogcgo/pprof.go
index 4460b93..00f2c42 100644
--- a/src/runtime/testdata/testprogcgo/pprof.go
+++ b/src/runtime/testdata/testprogcgo/pprof.go
@@ -26,6 +26,9 @@
salt2 = foo;
}
+void cpuHog2() {
+}
+
static int cpuHogCount;
struct cgoTracebackArg {
@@ -37,10 +40,13 @@
// pprofCgoTraceback is passed to runtime.SetCgoTraceback.
// For testing purposes it pretends that all CPU hits in C code are in cpuHog.
+// Issue #29034: At least 2 frames are required to verify all frames are captured
+// since runtime/pprof ignores the runtime.goexit base frame if it exists.
void pprofCgoTraceback(void* parg) {
struct cgoTracebackArg* arg = (struct cgoTracebackArg*)(parg);
arg->buf[0] = (uintptr_t)(cpuHog) + 0x10;
- arg->buf[1] = 0;
+ arg->buf[1] = (uintptr_t)(cpuHog2) + 0x4;
+ arg->buf[2] = 0;
++cpuHogCount;
}
diff --git a/src/runtime/testdata/testprogcgo/threadpprof.go b/src/runtime/testdata/testprogcgo/threadpprof.go
index 3da8296..37a2a1a 100644
--- a/src/runtime/testdata/testprogcgo/threadpprof.go
+++ b/src/runtime/testdata/testprogcgo/threadpprof.go
@@ -30,6 +30,9 @@
threadSalt2 = foo;
}
+void cpuHogThread2() {
+}
+
static int cpuHogThreadCount;
struct cgoTracebackArg {
@@ -44,7 +47,8 @@
void pprofCgoThreadTraceback(void* parg) {
struct cgoTracebackArg* arg = (struct cgoTracebackArg*)(parg);
arg->buf[0] = (uintptr_t)(cpuHogThread) + 0x10;
- arg->buf[1] = 0;
+ arg->buf[1] = (uintptr_t)(cpuHogThread2) + 0x4;
+ arg->buf[2] = 0;
__sync_add_and_fetch(&cpuHogThreadCount, 1);
}
