sync: delete dirty keys inside Map.LoadAndDelete
Fixes #40999
Change-Id: Ie32427e5cb5ed512b976b554850f50be156ce9f2
Reviewed-on: https://go-review.googlesource.com/c/go/+/250197
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
diff --git a/src/sync/map.go b/src/sync/map.go
index a61e2eb..9ad2535 100644
--- a/src/sync/map.go
+++ b/src/sync/map.go
@@ -274,6 +274,7 @@
e, ok = read.m[key]
if !ok && read.amended {
e, ok = m.dirty[key]
+ delete(m.dirty, key)
// Regardless of whether the entry was present, record a miss: this key
// will take the slow path until the dirty map is promoted to the read
// map.
diff --git a/src/sync/map_test.go b/src/sync/map_test.go
index 4ae989a..7f163ca 100644
--- a/src/sync/map_test.go
+++ b/src/sync/map_test.go
@@ -9,6 +9,7 @@
"reflect"
"runtime"
"sync"
+ "sync/atomic"
"testing"
"testing/quick"
)
@@ -171,3 +172,26 @@
}
}
}
+
+func TestIssue40999(t *testing.T) {
+ var m sync.Map
+
+ // Since the miss-counting in missLocked (via Delete)
+ // compares the miss count with len(m.dirty),
+ // add an initial entry to bias len(m.dirty) above the miss count.
+ m.Store(nil, struct{}{})
+
+ var finalized uint32
+
+ // Set finalizers that count for collected keys. A non-zero count
+ // indicates that keys have not been leaked.
+ for atomic.LoadUint32(&finalized) == 0 {
+ p := new(int)
+ runtime.SetFinalizer(p, func(*int) {
+ atomic.AddUint32(&finalized, 1)
+ })
+ m.Store(p, struct{}{})
+ m.Delete(p)
+ runtime.GC()
+ }
+}
