TypeName
DoNotLockOnObjectsWithWeakIdentity
CheckId
CA2002
Category
Microsoft.Reliability
Breaking Change
Non Breaking
A thread attempts to acquire a lock on an object that has a weak identity.
An object is said to have a weak identity when it can be directly accessed across application domain boundaries. A thread that tries to acquire a lock on an object that has a weak identity can be blocked by a second thread in a different application domain that has a lock on the same object. The following types have a weak identity and are flagged by the rule:
System..::.MarshalByRefObject
System..::.ExecutionEngineException
System..::.OutOfMemoryException
System..::.StackOverflowException
System..::.String
System.Reflection..::.MemberInfo
System.Reflection..::.ParameterInfo
System.Threading..::.Thread
To fix a violation of this rule, use an object from a type that is not in the list in the Description section.
Do not suppress a warning from this rule.
The following example shows some object locks that violate the rule.
Imports System Imports System.IO Imports System.Reflection Imports System.Threading Namespace ReliabilityLibrary Class WeakIdentities Sub SyncLockOnWeakId1() SyncLock GetType(WeakIdentities) End SyncLock End Sub Sub SyncLockOnWeakId2() Dim stream As New MemoryStream() SyncLock stream End SyncLock End Sub Sub SyncLockOnWeakId3() SyncLock "string" End SyncLock End Sub Sub SyncLockOnWeakId4() Dim member As MemberInfo = _ Me.GetType().GetMember("SyncLockOnWeakId1")(0) SyncLock member End SyncLock End Sub Sub SyncLockOnWeakId5() Dim outOfMemory As New OutOfMemoryException() SyncLock outOfMemory End SyncLock End Sub End Class End Namespace
using System; using System.IO; using System.Reflection; using System.Threading; namespace ReliabilityLibrary { class WeakIdentities { void LockOnWeakId1() { lock(typeof(WeakIdentities)) {} } void LockOnWeakId2() { MemoryStream stream = new MemoryStream(); lock(stream) {} } void LockOnWeakId3() { lock("string") {} } void LockOnWeakId4() { MemberInfo member = this.GetType().GetMember("LockOnWeakId1")[0]; lock(member) {} } void LockOnWeakId5() { OutOfMemoryException outOfMemory = new OutOfMemoryException(); lock(outOfMemory) {} } } }