Memory leak libcanrad

teremok · March 12, 2022, 8:04pm

When using the module, we periodically observe that the canardFree is trying to release the null pointer.
canardAlloc: 30688416 bytes: 40
canardFree: 30688416
canardAlloc: 31360032 bytes: 32
canardAlloc: 30720600 bytes: 12
canardFree nullptr

Can you tell me how to solve this problem? We use version 1.1

pavel.kirienko · March 13, 2022, 12:18am

This is not a problem. Freeing a null pointer is a no-op, and it is well-specified.

github.com

UAVCAN/libcanard/blob/224adff8eb191426dc3ae39f265ea72aa7d1e559/libcanard/canard.h#L354

    
      
          ///     - The memory shall be aligned at least at max_align_t.
          ///     - The execution time should be constant (O(1)).
          ///     - The worst-case memory fragmentation should be bounded and easily predictable.
          /// If the standard dynamic memory manager of the target platform does not satisfy the above requirements,
          /// consider using O1Heap: https://github.com/pavel-kirienko/o1heap.
          typedef void* (*CanardMemoryAllocate)(CanardInstance* ins, size_t amount);
          
          
/// The counterpart of the above -- this function is invoked to return previously allocated memory to the allocator.
          /// The semantics are similar to free():
          ///     - The pointer was previously returned by the allocation function.
          ///     - The pointer may be NULL, in which case the function shall have no effect.
          ///     - The execution time should be constant (O(1)).
          typedef void (*CanardMemoryFree)(CanardInstance* ins, void* pointer);
          
          
/// This is the core structure that keeps all of the states and allocated resources of the library instance.
          struct CanardInstance
          {
              /// User pointer that can link this instance with other objects.
              /// This field can be changed arbitrarily, the library does not access it after initialization.
              /// The default value is NULL.
              void* user_reference;