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Dangling pointers and wild pointers in computer programming are pointers that do not point to a valid object of the appropriate type. These are special cases of memory safety violations. More generally, dangling references and wild references are references that do not resolve to a valid destination.
They show the same erratic behaviour as dangling pointers, though they are less likely to stay undetected. Invalid free – passing an invalid address to free can corrupt the heap. Mismatched free – when multiple allocators are in use, attempting to free memory with a deallocation function of a different allocator [26]
Using non-owned memory: It is common to use pointers to access and modify memory. If such a pointer is a null pointer, dangling pointer (pointing to memory that has already been freed), or to a memory location outside of current stack or heap bounds, it is referring to memory that is not then possessed by the program. Using such pointers is a ...
This ensures that the pointer goes to either a valid object or nil, and avoids dangling pointers. Prior to the introduction of this feature, "weak references" referred to references that were not retaining, but were not set to nil when the object they pointed to was deallocated (equivalent to unsafe_unretained in ARC), thus possibly leading to ...
Tombstones are a mechanism to detect dangling pointers and mitigate the problems they can cause in computer programs. Dangling pointers can appear in certain computer programming languages, e.g. C, C++ and assembly languages. A tombstone is a structure that acts as an intermediary between a pointer and its target, often heap-dynamic data in memory.
In computer science, a memory leak is a type of resource leak that occurs when a computer program incorrectly manages memory allocations [1] in a way that memory which is no longer needed is not released. A memory leak may also happen when an object is stored in memory but cannot be accessed by the running code (i.e. unreachable memory). [2]
A code sanitizer is a programming tool that detects bugs in the form of undefined or suspicious behavior by a compiler inserting instrumentation code at runtime. The class of tools was first introduced by Google's AddressSanitizer (or ASan) of 2012, which uses directly mapped shadow memory to detect memory corruption such as buffer overflows or accesses to a dangling pointer (use-after-free).
Failures to adhere to this pattern, such as memory usage after a call to free (dangling pointer) or before a call to malloc (wild pointer), calling free twice ("double free"), etc., usually causes a segmentation fault and results in a crash of the program. These errors can be transient and hard to debug – for example, freed memory is usually ...