[Bug breakpoints/11094] cannot reexecute programs using the GDB JIT interface in shared libs

["edwintorok at gmail dot com" <sourceware-bugzilla@sourceware.org>]

------- Additional Comments From edwintorok at gmail dot com  2009-12-22 17:00 -------
(In reply to comment #5)
> Note that GDB turns off ASLR by default:
> 
> gdb64-cvs -nx -ex 'show disable-randomization' -ex 'quit'
> GNU gdb (GDB) 7.0.50.20091211-cvs
> ...
> This GDB was configured as "x86_64-unknown-linux-gnu".
> For bug reporting instructions, please see:
> <http://www.gnu.org/software/gdb/bugs/>.
> Disabling randomization of debuggee's virtual address space is on.
> 

Same here.

I think it tries to set the breakpoint too early, before the shared lib is loaded.

First run:
(gdb) b main
Breakpoint 1 at 0x4005f8: file bp_minus4.c, line 4.
(gdb) r
Starting program: /home/edwin/gdbbug/bp_minus4

Breakpoint 1, main () at bp_minus4.c:4
4           return foo();
(gdb) info sharedlibrary
>From                To                  Syms Read   Shared Object Library
0x000000381da00af0  0x000000381da16a24  Yes (*)     /lib64/ld-linux-x86-64.so.2
0x00007ffff7dfa510  0x00007ffff7dfa628  Yes         ./shared.so
0x000000381de1e730  0x000000381df0292c  Yes (*)     /lib/libc.so.6
(*): Shared library is missing debugging information.

Second run:
(gdb) r
The program being debugged has been started already.
Start it from the beginning? (y or n) y
Starting program: /home/edwin/gdbbug/bp_minus4
Warning:
Cannot insert breakpoint -2.
Error accessing memory address 0x7ffff7dfa5dc: Input/output error.

(gdb) info sharedlibrary
>From                To                  Syms Read   Shared Object Library
0x000000381da00af0  0x000000381da16a24  Yes (*)     /lib64/ld-linux-x86-64.so.2
(*): Shared library is missing debugging information.

And here is /proc/maps for the process
$ ps aux|grep gdb
edwin    10001  0.2  0.2  37260 10264 pts/1    S+   18:58   0:00 gdb ./bp_minus4
edwin    10020  0.0  0.0    220    24 pts/1    T    18:59   0:00
/home/edwin/gdbbug/bp_minus4
edwin    10033  0.0  0.0   7288   784 pts/2    S+   18:59   0:00 grep gdb

$ cat /proc/10020/maps
00400000-00401000 r-xp 00000000 fd:02 5389238                           
/home/edwin/gdbbug/bp_minus4
00600000-00601000 rw-p 00000000 fd:02 5389238                           
/home/edwin/gdbbug/bp_minus4
381da00000-381da1d000 r-xp 00000000 09:03 260632                        
/lib/ld-2.10.2.so
381dc1c000-381dc1e000 rw-p 0001c000 09:03 260632                        
/lib/ld-2.10.2.so
7ffff7ffe000-7ffff7fff000 r-xp 00000000 00:00 0                          [vdso]
7ffffffea000-7ffffffff000 rw-p 00000000 00:00 0                          [stack]
ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0                  [vsyscall]

-- 


http://sourceware.org/bugzilla/show_bug.cgi?id=11094

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