title: Gdb Cannot access memory at address
body: <p>I want to use breakpoint in the UPtest function to stop at 0x000000000040124c.</p>
  
  <p><a href="https://i.stack.imgur.com/UK60S.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/UK60S.png" alt="enter image description here"></a>
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  <p>run 111 222 333
  <a href="https://i.stack.imgur.com/FoXiY.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/FoXiY.png" alt="enter image description here"></a>
  <a href="https://i.stack.imgur.com/tyJqI.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/tyJqI.png" alt="enter image description here"></a>
  I need to display the 32 records at the top of the stack.</p>
  
  <p>x / 32wx $ esp, but show Cannot access memory at address 0xffffffffffffe0a0.</p>
  
  <p>I want to find the return address of the main program, how do I change it to display it?Like the picture below.</p>
  
  <p><a href="https://i.stack.imgur.com/IfnHx.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/IfnHx.png" alt="enter image description here"></a></p>