I get a SIGSEGEV segment violation when using an inline assembly jmp instruction to jump to a block of code saved in a data area. A test program is shown below. Thanks for your help!

// jump.c - Employ inline assembly to perform a jump into code block.
// To compile: gcc -gstabs -o jump jump.c
// To show assembler: gcc -S jump.c
// To generate obj: gcc -c jump.c
// To disassemble: objdump -d jump.o
// To debug: gdb jump
#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>

typedef unsigned long ulong;
int main()
{
    char *apIp;
    char *apBp = NULL, *apCp, *apEp;
    char **apLp; // Ptr to place to place holding a char ptr
    int aSize = 100; // code size in bytes
    int aRet;
    unsigned long aB = 2;

    // Allocate a block of memory to hold code. Align to a page boundry
    apBp = malloc(aSize + 4096);
    aB = (unsigned long)apBp;
    aB += 4095;
    aB &= 0xFFFFF000;
    apIp = apCp = (char *)aB;
    apEp = apIp + aSize;

    // Fill code block with no-ops
    while (apCp < apEp)
        *apCp++ = 0x90;

    // End code block with a jump back to lDone
    apCp = apEp - 6;
    *apCp++ = 0xFF; // jmp offset32
    *apCp++ = 0x25;
    apLp = (char **)apCp;
    *apLp = &&lDone;

    // Allow execute permission in data block.
    aRet = mprotect(apIp, aSize, PROT_EXEC | PROT_WRITE | PROT_READ);

    // Various jump instructions.
    ///asm ("jmp lDone"); // FF 25 ofs jmp lDone
    /// asm ("movl %0, %%eax\n\t" // 8B 45 F8 mov -8(%epb), %eax
    /// "jmp *%%eax" : :"m" (apIp)); // FF E0 jmp *%eax
    /// asm (".intel_syntax\n\tjmp dword ptr [apX]"); // Does not work
    /// asm ("leal %0, %%eax\n\t" // 8D 4f F8 lea -8(%ebp), %eax
    /// "jmp *(%%eax)" : : "m" (apIp));// FF 20 jmp *(%eax)
    asm ("jmp *%0" : : "m" (apIp)); // FF 65 F8 jmp *-8(%epb)
    printf("This statement is not reachable.\n");
    free(apBp);
    exit (0);
    // Finish up here
lDone:
    printf("Return from code block\n");
    free(apBp);
    return 0;
}