cache: fix possible concurrent maps write on parent release

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>
moby · Nov 12, 2019 · 31beb83 · 31beb83
1 parent 2a9b6b5
commit 31beb83
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Showing 2 changed files with 6 additions and 6 deletions.
diff --git a/cache/manager.go b/cache/manager.go
@@ -156,6 +156,8 @@ func (cm *cacheManager) get(ctx context.Context, id string, fromSnapshotter bool
 			return nil, errors.Wrapf(ErrLocked, "%s is locked", id)
 		}
 		if rec.equalImmutable != nil {
+			rec.equalImmutable.mu.Lock()
+			defer rec.equalImmutable.mu.Unlock()
 			return rec.equalImmutable.ref(triggerUpdate), nil
 		}
 		return rec.mref(triggerUpdate).commit(ctx)

diff --git a/cache/refs.go b/cache/refs.go
@@ -185,7 +185,10 @@ func (cr *cacheRecord) Mount(ctx context.Context, readonly bool) (snapshot.Mount
 func (cr *cacheRecord) remove(ctx context.Context, removeSnapshot bool) error {
 	delete(cr.cm.records, cr.ID())
 	if cr.parent != nil {
-		if err := cr.parent.release(ctx); err != nil {
+		cr.parent.mu.Lock()
+		err := cr.parent.release(ctx)
+		cr.parent.mu.Unlock()
+		if err != nil {
 			return err
 		}
 	}
@@ -401,11 +404,6 @@ func (sr *mutableRef) release(ctx context.Context) error {
 				return err
 			}
 		}
-		if sr.parent != nil {
-			if err := sr.parent.release(ctx); err != nil {
-				return err
-			}
-		}
 		return sr.remove(ctx, true)
 	} else {
 		if sr.updateLastUsed() {