Logging memory allocation functions using DLL injection

Question

I have a simple program let's call it a victim:

#include <stdio.h>
#include <stdlib.h>

int
main(void)
{
    int *a = malloc(200);
    printf("%p\n", a);
}

And I want to inject a shared object into this program that will log all the calls to the malloc function. So it will works like a memory logger:

#define _GNU_SOURCE

#include <dlfcn.h>
#include <stdio.h>
#include <stdlib.h>

void *
malloc(size_t n)
{
    static void * (*real_malloc)(size_t) = NULL;

    if (real_malloc == NULL) {
        real_malloc = dlsym(RTLD_NEXT, "malloc");

        if (real_malloc == NULL) {
#if 0
            printf("MEMORY FILTER: can't find the real malloc() function: %s\n", dlerror());
#endif
            exit(EXIT_FAILURE);
        }
    }

    void *result = real_malloc(n);

#if 0
    if (result != NULL)
        printf("MEMORY FILTER: allocated %zu bytes at address %p.\n", n, result);
    else
        printf("MEMORY FILTER: failed to allocate %zu bytes.\n", n);
#endif

    return result;
}

And then I run the victim as follows:

$ LD_LIBRARY_PATH=. LD_PRELOAD=libmemlog.so ./victim
0x55e0747792a0

It works fine but when I uncomment #if 0 ... #endif blocks when the printf function is called then I get a segmentation fault. This is happens because printf calls malloc inside itself and we got an endless recursion which eventually crushes.

How can I get logging work in this case?