storage: don't use global rand in test configs

I was looking into a test timeout under race and saw one spot where we
use the global rand under race. We have a few spots like this in the
storage folder, so this commit fixes them.

Release note: None

Author: yuzefovich

pkg/storage/BUILD.bazel

@@ -85,6 +85,7 @@ go_library(
         "//pkg/util/metamorphic",
         "//pkg/util/mon",
         "//pkg/util/protoutil",
+        "//pkg/util/randutil",
         "//pkg/util/syncutil",
         "//pkg/util/sysutil",
         "//pkg/util/timeutil",

pkg/storage/intent_interleaving_iter.go

@@ -17,6 +17,7 @@ import (
 	"github.com/cockroachdb/cockroach/pkg/roachpb"
 	"github.com/cockroachdb/cockroach/pkg/util"
 	"github.com/cockroachdb/cockroach/pkg/util/protoutil"
+	"github.com/cockroachdb/cockroach/pkg/util/randutil"
 	"github.com/cockroachdb/errors"
 	"github.com/cockroachdb/pebble"
 )
@@ -1477,6 +1478,7 @@ func (i *intentInterleavingIter) assertInvariants() error {
 // changes to unsafe keys retrieved from MVCCIterators.
 type unsafeMVCCIterator struct {
 	MVCCIterator
+	rng           *rand.Rand
 	keyBuf        []byte
 	rawKeyBuf     []byte
 	rawMVCCKeyBuf []byte
@@ -1485,7 +1487,8 @@ type unsafeMVCCIterator struct {
 // gcassert:inline
 func maybeWrapInUnsafeIter(iter MVCCIterator) MVCCIterator {
 	if util.RaceEnabled {
-		return &unsafeMVCCIterator{MVCCIterator: iter}
+		rng, _ := randutil.NewPseudoRand()
+		return &unsafeMVCCIterator{MVCCIterator: iter, rng: rng}
 	}
 	return iter
 }
@@ -1547,7 +1550,7 @@ func (i *unsafeMVCCIterator) UnsafeRawMVCCKey() []byte {
 }
 
 func (i *unsafeMVCCIterator) mangleBufs() {
-	if rand.Intn(2) == 0 {
+	if i.rng.Intn(2) == 0 {
 		for _, b := range [3][]byte{i.keyBuf, i.rawKeyBuf, i.rawMVCCKeyBuf} {
 			for i := range b {
 				b[i] = 0

pkg/storage/pebbleiter/BUILD.bazel

@@ -14,6 +14,7 @@ go_library(
     visibility = ["//visibility:public"],
     deps = [
         "//pkg/util",
+        "//pkg/util/randutil",
         "@com_github_cockroachdb_errors//:errors",
         "@com_github_cockroachdb_pebble//:pebble",
     ],

pkg/storage/pebbleiter/crdb_test_on.go

@@ -13,6 +13,7 @@ import (
 	"time"
 
 	"github.com/cockroachdb/cockroach/pkg/util"
+	"github.com/cockroachdb/cockroach/pkg/util/randutil"
 	"github.com/cockroachdb/errors"
 	"github.com/cockroachdb/pebble"
 )
@@ -26,12 +27,14 @@ type Iterator = *assertionIter
 // MaybeWrap returns the provided Pebble iterator, wrapped with double close
 // detection.
 func MaybeWrap(iter *pebble.Iterator) Iterator {
-	return &assertionIter{Iterator: iter, closedCh: make(chan struct{})}
+	rng, _ := randutil.NewPseudoRand()
+	return &assertionIter{Iterator: iter, rng: rng, closedCh: make(chan struct{})}
 }
 
 // assertionIter wraps a *pebble.Iterator with assertion checking.
 type assertionIter struct {
 	*pebble.Iterator
+	rng      *rand.Rand
 	closed   bool
 	closedCh chan struct{}
 	// unsafeBufs hold buffers used for returning values with short lifetimes to
@@ -243,11 +246,11 @@ func (i *assertionIter) PrevWithLimit(limit []byte) pebble.IterValidityState {
 // to the caller. This is used to ensure that the client respects the Pebble
 // iterator interface and the lifetimes of buffers it returns.
 func (i *assertionIter) maybeMangleBufs() {
-	if rand.Intn(2) == 0 {
+	if i.rng.Intn(2) == 0 {
 		idx := i.unsafeBufs.idx
 		zero(i.unsafeBufs.key[idx])
 		zero(i.unsafeBufs.val[idx])
-		if rand.Intn(2) == 0 {
+		if i.rng.Intn(2) == 0 {
 			// Switch to a new buffer for the next iterator position.
 			i.unsafeBufs.idx = (i.unsafeBufs.idx + 1) % 2
 		}
@@ -273,7 +276,7 @@ func (i *assertionIter) maybeSaveAndMangleRangeKeyBufs() {
 	// Randomly zero them to ensure we catch bugs where they're reused.
 	idx := i.rangeKeyBufs.idx
 	mangleBuf := &i.rangeKeyBufs.bufs[idx]
-	if rand.Intn(2) == 0 {
+	if i.rng.Intn(2) == 0 {
 		mangleBuf.mangle()
 	}
 	// If the new iterator position has range keys, copy them to our buffers.
@@ -283,7 +286,7 @@ func (i *assertionIter) maybeSaveAndMangleRangeKeyBufs() {
 	if _, hasRange := i.Iterator.HasPointAndRange(); !hasRange {
 		return
 	}
-	switchBuffers := rand.Intn(2) == 0
+	switchBuffers := i.rng.Intn(2) == 0
 	if switchBuffers {
 		// Switch to a new buffer for the new range key state.
 		i.rangeKeyBufs.idx = (idx + 1) % 2