summary refs log tree commit diff stats
path: root/results/scraper/launchpad/1528239
blob: c3e0e67e03ac71ea3e89da3a462626c23e41f39a (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
Unable to debug PIE binaries with QEMU gdb stub.

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.

GDB server itself actually supports PIE binaries.

This patch https://<email address hidden>/ fixes the issue.

Patch has been included in QEMU v4.2:
https://git.qemu.org/?p=qemu.git;a=commitdiff;h=dc12567a53c88d7a91b9