Dynamic Memory Scope for Preventing Invalid Access
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Solution Overview
Problem
In enterprise-class software, concurrent memory allocation and deallocation requests from multiple threads or processes can lead to memory corruption due to invalid memory access, making it difficult to identify and correct the root cause of errors or crashes, as these issues often manifest non-deterministically and far removed from the actual perpetrator.
Innovation Solution
Implementing a system that defines a dynamic scope for memory operations, ensuring monotonically increasing memory allocation and protecting deallocated memory to prevent reuse, using OS and hardware-level facilities to enforce memory access permissions, thereby trapping and terminating processes attempting to access protected memory, and removing protections once the operation completes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If memory is shared and reused across multiple threads/processes, then memory utilization efficiency is improved, but the risk of memory corruption and invalid access increases
Solution Approach 1:
The system performs preliminary actions by defining a dynamic scope and establishing monotonic allocation rules before memory operations occur. When memory is deallocated, the system proactively protects it from future allocation within the same scope, preventing invalid access before it can happen. This preliminary protection mechanism ensures that even though memory is shared and reused, the reliability is maintained by preventing corruption at the source.
2Adaptability or versatility
If memory allocation is dynamic and flexible, then adaptability is improved, but the difficulty of detecting and measuring invalid access increases
Solution Approach 1:
The system implements feedback by continuously tracking memory allocation and deallocation events within a defined scope. When memory is deallocated, the system provides feedback by protecting that memory region and monitoring for any subsequent access attempts. If invalid access is detected, the system immediately terminates the offending thread, providing real-time detection and measurement capability that works seamlessly with dynamic memory allocation.
Solution Approach 2:
The system uses memory protection markers (analogous to color changes) to indicate the state of memory regions. When memory is deallocated, it is marked as protected/unavailable for allocation. This visual/state-based indication makes it easy to detect and measure the state of memory regions, transforming the invisible problem of invalid access into a detectable condition through protection markers.
3Reliability
If memory protection mechanisms are implemented, then reliability is improved, but device complexity increases
Solution Approach 1:
The system segments memory management by introducing dynamic scopes that partition memory allocation into isolated regions. Each scope maintains its own allocation history and protection state, allowing memory protection to be applied locally rather than globally. This segmentation reduces complexity by limiting the scope of protection tracking to relevant memory regions only, while still providing comprehensive safety within each segment.
Data Source
AI summary
Methods, computer readable media, and devices for identifying and preventing invalid memory access. A method may include defining a dynamic scope for an operation, receiving a request to allocate a portion of the range of shared memory, allocating a monotonically increasing portion of the range of shared memory such that a subsequent request to allocate memory is allocated a different portion of the range of shared memory, receiving a request to deallocate the allocated portion of the range of shared memory, deallocating the allocated portion of the range of shared memory by protecting the deallocated portion of the range of shared memory from any subsequent access, and in response to an access of the protected deallocated portion of the range of shared memory by one of the one or more threads or processes of the operation, trapping and terminating the one thread or process.