internal/fuzz: fix -fuzzminimizetime with 'x' bug
Fixes #48928
Change-Id: I3825ec615ab5fc19389ef4c10ad1042005a3761c
Reviewed-on: https://go-review.googlesource.com/c/go/+/355450
Trust: Katie Hockman <katie@golang.org>
Run-TryBot: Katie Hockman <katie@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
diff --git a/src/cmd/go/testdata/script/test_fuzz_fuzztime.txt b/src/cmd/go/testdata/script/test_fuzz_fuzztime.txt
index 7d644b4..9c9972f 100644
--- a/src/cmd/go/testdata/script/test_fuzz_fuzztime.txt
+++ b/src/cmd/go/testdata/script/test_fuzz_fuzztime.txt
@@ -16,13 +16,24 @@
# Timeout should not cause inputs to be written as crashers.
! exists testdata/fuzz
-# When we use fuzztime with an "x" suffix, it runs a specific number of times.
-# This fuzz function creates a file with a unique name ($pid.$count) on each run.
-# We count the files to find the number of runs.
-mkdir count
env GOCACHE=$WORK/tmp
-go test -fuzz=FuzzCount -fuzztime=1000x -fuzzminimizetime=1x
-go run check_file_count.go 1000
+
+# When we use fuzztime with an "x" suffix, it runs a specific number of times.
+# This fuzz function creates a file with a unique name ($pid.$count) on each
+# run. We count the files to find the number of runs.
+mkdir count
+go test -fuzz=FuzzTestCount -fuzztime=1000x -fuzzminimizetime=1x
+go run check_file_count.go count 1000
+
+# When we use fuzzminimizetime with an "x" suffix, it runs a specific number of
+# times while minimizing. This fuzz function creates a file with a unique name
+# ($pid.$count) on each run once the first crash has been found. That means that
+# there should be one file for each execution of the fuzz function during
+# minimization, so we count these to determine how many times minimization was
+# run.
+mkdir minimizecount
+! go test -fuzz=FuzzMinimizeCount -fuzzminimizetime=3x -parallel=1
+go run check_file_count.go minimizecount 3
-- go.mod --
module fuzz
@@ -45,7 +56,7 @@
"testing"
)
-func FuzzCount(f *testing.F) {
+func FuzzTestCount(f *testing.F) {
pid := os.Getpid()
n := 0
f.Fuzz(func(t *testing.T, _ []byte) {
@@ -56,6 +67,36 @@
n++
})
}
+-- fuzz_minimize_count_test.go --
+package fuzz
+
+import (
+ "bytes"
+ "fmt"
+ "os"
+ "testing"
+)
+
+func FuzzMinimizeCount(f *testing.F) {
+ pid := os.Getpid()
+ n := 0
+ seed := bytes.Repeat([]byte("a"), 357)
+ f.Add(seed)
+ crashFound := false
+ f.Fuzz(func(t *testing.T, b []byte) {
+ if crashFound {
+ name := fmt.Sprintf("minimizecount/%v.%d", pid, n)
+ if err := os.WriteFile(name, nil, 0666); err != nil {
+ t.Fatal(err)
+ }
+ n++
+ }
+ if !bytes.Equal(b, seed) { // this should happen right away
+ crashFound = true
+ t.Error("minimize this!")
+ }
+ })
+}
-- check_file_count.go --
// +build ignore
@@ -68,13 +109,13 @@
)
func main() {
- dir, err := os.ReadDir("count")
+ dir, err := os.ReadDir(os.Args[1])
if err != nil {
fmt.Fprintln(os.Stderr, err)
os.Exit(1)
}
got := len(dir)
- want, _ := strconv.Atoi(os.Args[1])
+ want, _ := strconv.Atoi(os.Args[2])
if got != want {
fmt.Fprintf(os.Stderr, "got %d files; want %d\n", got, want)
os.Exit(1)
diff --git a/src/internal/fuzz/fuzz.go b/src/internal/fuzz/fuzz.go
index a8bbd60..03071d5 100644
--- a/src/internal/fuzz/fuzz.go
+++ b/src/internal/fuzz/fuzz.go
@@ -825,9 +825,11 @@
}
}
}
- remaining := c.opts.Limit - c.count - c.countWaiting
- if input.limit > remaining {
- input.limit = remaining
+ if c.opts.Limit > 0 {
+ remaining := c.opts.Limit - c.count - c.countWaiting
+ if input.limit > remaining {
+ input.limit = remaining
+ }
}
return input, true
}
