Method and apparatus for detecting references to deallocated mem

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39549702, 395412, 395600, 395650, 39518314, 39518318, 3642566, 36426791, 3642822, 3649675, 364DIG1, G06F 1202, G06F 1210

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active

055599800

ABSTRACT:
A system and means for identifying references by a process or a subprogram of a process to deallocated memory in a dynamic memory allocation system. The system and method are effective in identifying such references even before they have manifested themselves, and also in identifying the perpetrators of such references. The system and method make use of that portion of the address space of the process which is not otherwise used. A dynamic memory allocation function responds to a requestor's request for memory allocation by mapping memory which the function is allocating to the requestor into otherwise-unused virtual address space, recording this mapping in the system's memory map, and returning the virtual address to the requestor for use in referencing the allocated memory. Hence, any attempted access by the requestor to the allocated memory uses the virtual address, and the virtual address must be translated through the process memory map before the access can be established. A dynamic memory deallocation function responds to a requestor's request for memory deallocation by deleting from the process memory map the mapping between the memory which is being deallocated and the corresponding virtual address. Hence, any subsequent attempted access by the requestor to the deallocated memory fails on account of the corresponding entry in the process memory map being empty and thus unavailable for completion of the requisite address translation. This failure is trapped, recorded, and reported by the system's conventional fault-management mechanisms.

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