pprof_test.go

     1  // Copyright 2025 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package main
     6  
     7  import (
     8  	"bytes"
     9  	"net/http"
    10  	"os"
    11  	"runtime/trace"
    12  	"strings"
    13  	"testing"
    14  	"testing/synctest"
    15  	"time"
    16  
    17  	itrace "internal/trace"
    18  	"internal/trace/testtrace"
    19  )
    20  
    21  // Regression test for go.dev/issue/74850.
    22  func TestSyscallProfile74850(t *testing.T) {
    23  	testtrace.MustHaveSyscallEvents(t)
    24  
    25  	var buf bytes.Buffer
    26  	err := trace.Start(&buf)
    27  	if err != nil {
    28  		t.Fatalf("start tracing: %v", err)
    29  	}
    30  
    31  	synctest.Test(t, func(t *testing.T) {
    32  		go hidden1(t)
    33  		go hidden2(t)
    34  		go visible(t)
    35  		synctest.Wait()
    36  		time.Sleep(1 * time.Millisecond)
    37  		synctest.Wait()
    38  	})
    39  	trace.Stop()
    40  
    41  	if t.Failed() {
    42  		return
    43  	}
    44  
    45  	parsed, err := parseTrace(&buf, int64(buf.Len()))
    46  	if err != nil {
    47  		t.Fatalf("parsing trace: %v", err)
    48  	}
    49  
    50  	records, err := pprofByGoroutine(computePprofSyscall(), parsed)(&http.Request{})
    51  	if err != nil {
    52  		t.Fatalf("failed to generate pprof: %v\n", err)
    53  	}
    54  
    55  	for _, r := range records {
    56  		t.Logf("Record: n=%d, total=%v", r.Count, r.Time)
    57  		for _, f := range r.Stack {
    58  			t.Logf("\t%s", f.Func)
    59  			t.Logf("\t\t%s:%d @ 0x%x", f.File, f.Line, f.PC)
    60  		}
    61  	}
    62  	if len(records) == 0 {
    63  		t.Error("empty profile")
    64  	}
    65  
    66  	// Make sure we see the right frames.
    67  	wantSymbols := []string{"cmd/trace.visible", "cmd/trace.hidden1", "cmd/trace.hidden2"}
    68  	haveSymbols := make([]bool, len(wantSymbols))
    69  	for _, r := range records {
    70  		for _, f := range r.Stack {
    71  			for i, s := range wantSymbols {
    72  				if strings.Contains(f.Func, s) {
    73  					haveSymbols[i] = true
    74  				}
    75  			}
    76  		}
    77  	}
    78  	for i, have := range haveSymbols {
    79  		if !have {
    80  			t.Errorf("expected %s in syscall profile", wantSymbols[i])
    81  		}
    82  	}
    83  }
    84  
    85  // Regression test: pcsForStack must not panic when the stack has more than
    86  // pprofMaxStack (128) frames. Before the fix, pcs[i] was written before
    87  // checking i >= len(pcs), causing an index-out-of-range panic.
    88  func TestFillPCsOverflow(t *testing.T) {
    89  	var pcs [pprofMaxStack]uint64
    90  
    91  	// Build a stack with more frames than pprofMaxStack.
    92  	n := pprofMaxStack + 10
    93  	frames := make([]itrace.StackFrame, n)
    94  	for i := range frames {
    95  		frames[i].PC = uint64(0x1000 + i)
    96  	}
    97  	stack := itrace.MakeStack(frames)
    98  
    99  	// This must not panic.
   100  	pcsForStack(stack, &pcs)
   101  
   102  	// Verify the first pprofMaxStack entries were written correctly.
   103  	for i := 0; i < pprofMaxStack; i++ {
   104  		if pcs[i] != uint64(0x1000+i) {
   105  			t.Errorf("pcs[%d] = %#x, want %#x", i, pcs[i], 0x1000+i)
   106  		}
   107  	}
   108  }
   109  
   110  func stat(t *testing.T) {
   111  	_, err := os.Stat(".")
   112  	if err != nil {
   113  		t.Errorf("os.Stat: %v", err)
   114  	}
   115  }
   116  
   117  func hidden1(t *testing.T) {
   118  	stat(t)
   119  }
   120  
   121  func hidden2(t *testing.T) {
   122  	stat(t)
   123  	stat(t)
   124  }
   125  
   126  func visible(t *testing.T) {
   127  	stat(t)
   128  	time.Sleep(1 * time.Millisecond)
   129  }
   130
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