[Qemu-devel] [Bug 1528239] Re: Unable to debug PIE binaries with QEMU gdb stub.

[Lukas Durfina]

This patch
https://patchew.org/QEMU/address@hidden/ fixes
the issue.

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https://bugs.launchpad.net/bugs/1528239

Title:
  Unable to debug PIE binaries with QEMU gdb stub.

Status in QEMU:
  New

Bug description:
  The issue occurs on current trunk:

  max@max:~/build/qemu$ cat test.c
  #include <stdio.h>

  int main() {
    printf("Hello, world!\n");
    return 0;
  }

  max@max:~/build/qemu$ gcc test.c -fPIC -pie -o bad.x
  max@max:~/build/qemu$ ./x86_64-linux-user/qemu-x86_64 -g 1234 bad.x 
  .............................

  
  max@max:~/build/qemu$ gdb
  GNU gdb (Ubuntu 7.7.1-0ubuntu5~14.04.2) 7.7.1
  
........................................................................................
  (gdb) file bad.x
  Reading symbols from bad.x...(no debugging symbols found)...done.
  (gdb) b main
  Breakpoint 1 at 0x779
  (gdb) target remote localhost:1234
  Remote debugging using localhost:1234
  Reading symbols from /lib64/ld-linux-x86-64.so.2...warning: the debug 
information found in "/lib64/ld-2.19.so" does not match 
"/lib64/ld-linux-x86-64.so.2" (CRC mismatch).

  Reading symbols from /usr/lib/debug//lib/x86_64-linux-gnu/ld-2.19.so...done.
  done.
  Loaded symbols for /lib64/ld-linux-x86-64.so.2
  Error in re-setting breakpoint 1: Cannot access memory at address 0x775
  Error in re-setting breakpoint 1: Cannot access memory at address 0x775
  0x0000004000a042d0 in _start () from /lib64/ld-linux-x86-64.so.2
  (gdb) c
  Continuing.
  [Inferior 1 (Remote target) exited normally]
  (gdb) 

  
  max@max:~/build/qemu$ cat config.log
  # Configured with: '/home/max/src/qemu/configure' 
'--prefix=/home/max/install/qemu' 
'--target-list=arm-linux-user,aarch64-linux-user,x86_64-linux-user' '--static'

  
  W/O QEMU or -pie flag breakpoint on main works fine.

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