The software does not properly acquire a lock on a resource, or it does not properly release a lock on a resource, leading to unexpected resource state changes and behaviors.
Time of Introduction
Architecture and Design
Implementation
Common Consequences
Scope
Effect
Availability
Technical Impact: DoS: resource consumption
(CPU)
Inconsistent locking discipline can lead to deadlock.
Demonstrative Examples
Example 1
In the following Java snippet, methods are defined to get and set a
long field in an instance of a class that is shared across multiple threads.
Because operations on double and long are nonatomic in Java, concurrent
access may cause unexpected behavior. Thus, all operations on long and
double fields should be synchronized.
(Bad Code)
Example
Language: Java
private long someLongValue;
public long getLongValue() {
return someLongValue;
}
public void setLongValue(long l) {
someLongValue = l;
}
Potential Mitigations
Use industry standard APIs to implement locking mechanism.
Description
