[Bug 1901966] Re: Unable to stop at breakpoint in 32-bit executable
Hyun
1901966 at bugs.launchpad.net
Tue Oct 5 00:02:56 UTC 2021
I have same issue as James described. A static link of execution file, "-static" option in gcc, works in gdb while shared is not.
Any updates on this issue?
bulssi at bulssi:~/work$ cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=20.04
DISTRIB_CODENAME=focal
DISTRIB_DESCRIPTION="Ubuntu 20.04 LTS"
bulssi at bulssi:~/work$ lscpu
Architecture: aarch64
CPU op-mode(s): 32-bit, 64-bit
Byte Order: Little Endian
CPU(s): 4
On-line CPU(s) list: 0,1
Off-line CPU(s) list: 2,3
Thread(s) per core: 1
Core(s) per socket: 2
Socket(s): 1
Vendor ID: ARM
Model: 0
Model name: Cortex-A55
Stepping: r2p0
BogoMIPS: 100.00
L2 cache: 256 KiB
L3 cache: 512 KiB
Vulnerability Itlb multihit: Not affected
Vulnerability L1tf: Not affected
Vulnerability Mds: Not affected
Vulnerability Meltdown: Not affected
Vulnerability Spec store bypass: Not affected
Vulnerability Spectre v1: Mitigation; __user pointer sanitization
Vulnerability Spectre v2: Not affected
Vulnerability Srbds: Not affected
Vulnerability Tsx async abort: Not affected
Flags: fp asimd evtstrm aes pmull sha1 sha2 crc32 atomics fphp asimdhp cpuid asimdrdm lrcpc dcpop asimddp
bulssi at bulssi:~/work$ uname -a
Linux bulssi 5.4.96+ #4 SMP PREEMPT Tue Sep 28 02:25:02 UTC 2021 aarch64 aarch64 aarch64 GNU/Linux
bulssi at bulssi:~/work$ cat test.c
#include <stdio.h>
int main (int argc, char **argv)
{
printf ("hello\n");
return 0;
}
bulssi at bulssi:~/work$ arm-linux-gnueabihf-gcc -o a32.out test.c
bulssi at bulssi:~/work$ ./a32.out
hello
bulssi at bulssi:~/work$ gdb ./a32.out
GNU gdb (Ubuntu 9.1-0ubuntu1) 9.1
Copyright (C) 2020 Free Software Foundation, Inc.
...
Reading symbols from ./a32.out...
(No debugging symbols found in ./a32.out)
(gdb) set architecture arm
The target architecture is assumed to be arm
(gdb) r
Starting program: /home/bulssi/work/a32.out
^C
Program received signal SIGINT, Interrupt.
0xf7fd12c4 in ?? () from /lib/ld-linux-armhf.so.3
(gdb) bt
#0 0xf7fd12c4 in ?? () from /lib/ld-linux-armhf.so.3
#1 0xf7fc81e4 in ?? () from /lib/ld-linux-armhf.so.3
Backtrace stopped: previous frame identical to this frame (corrupt stack?)
(gdb)
(gdb) set debug infrun 1
(gdb) run
The program being debugged has been started already.
Start it from the beginning? (y or n) y
Starting program: /home/bulssi/work/a32.out
infrun: infrun_async(1)
infrun: proceed (addr=0xf7fc5a80, signal=GDB_SIGNAL_0)
infrun: proceed: resuming process 19335
infrun: resume (step=0, signal=GDB_SIGNAL_0), trap_expected=0, current thread [process 19335] at 0xf7fc5a80
infrun: prepare_to_wait
infrun: target_wait (-1.0.0, status) =
infrun: -1.0.0 [process -1],
infrun: status->kind = ignore
infrun: handle_inferior_event status->kind = ignore
infrun: prepare_to_wait
^Cinfrun: target_wait (-1.0.0, status) =
infrun: 19335.19335.0 [process 19335],
infrun: status->kind = stopped, signal = GDB_SIGNAL_INT
infrun: handle_inferior_event status->kind = stopped, signal = GDB_SIGNAL_INT
infrun: stop_pc = 0xf7fd12fe
infrun: random signal (GDB_SIGNAL_INT)
infrun: stop_waiting
infrun: stop_all_threads
infrun: stop_all_threads, pass=0, iterations=0
infrun: process 19335 not executing
infrun: stop_all_threads, pass=1, iterations=1
infrun: process 19335 not executing
infrun: stop_all_threads done
Program received signal SIGINT, Interrupt.
0xf7fd12fe in ?? () from /lib/ld-linux-armhf.so.3
infrun: infrun_async(0)
(gdb) bt
#0 0xf7fd12fe in ?? () from /lib/ld-linux-armhf.so.3
#1 0xf7fc81e4 in ?? () from /lib/ld-linux-armhf.so.3
Backtrace stopped: previous frame identical to this frame (corrupt stack?)
(gdb) quit
bulssi at bulssi:~/work$ arm-linux-gnueabihf-gcc -static -o a32.out test.c
bulssi at bulssi:~/work$ file a32.out
a32.out: ELF 32-bit LSB executable, ARM, EABI5 version 1 (GNU/Linux), statically linked, BuildID[sha1]=e1f35070879490a0c809ac5b4b32159457ae0150, for GNU/Linux 3.2.0, not stripped
bulssi at bulssi:~/work$ gdb a32.out
GNU gdb (Ubuntu 9.1-0ubuntu1) 9.1
Copyright (C) 2020 Free Software Foundation, Inc.
...
Reading symbols from a32.out...
(No debugging symbols found in a32.out)
(gdb) r
Starting program: /home/bulssi/work/a32.out
hello
[Inferior 1 (process 19358) exited normally]
(gdb) quit
bulssi at bulssi:~/work$
--
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to gdb in Ubuntu.
https://bugs.launchpad.net/bugs/1901966
Title:
Unable to stop at breakpoint in 32-bit executable
Status in gdb package in Ubuntu:
Confirmed
Bug description:
I believe I'm having the problem described in #1846557 and #1848200.
Those bugs were reported fixed in 8.1.1 but I'm observing them in 9.2
so I suspect a regression (in fact, if I read the notes correctly, the
earlier reports were from another regression!).
I create a new EC2 server on AWS with Ubuntu Server 20.04 LTS (64-bit
Arm) then perform the following installs (not sure what is needed or
if something is missing):
```
sudo dpkg --add-architecture armhf
sudo apt update
sudo apt upgrade -y
sudo apt install -y build-essential vim binutils-arm-linux-gnueabi \
gdb libc6:armhf libstdc++6:armhf
```
Then I create hello.s:
```
.text
.global _start
_start:
MOV R7, #4
MOV R0, #1
LDR R1, =hello
LDR R2, =hello_size
SWI 0
MOV R7, #1
SWI 0
.data
hello: .asciz "Hello world!\n"
.equ hello_size, (.-hello)
```
Then I assemble, link, and run, all with success. Finally, I try to
debug:
```
$ arm-linux-gnueabi-as -ggdb -mcpu=cortex-a57 -o out.o hello.s
$ arm-linux-gnueabi-ld out.o -dynamic-linker=/usr/lib/ld-linux-armhf.so.3 -o out
$ rm out.o
$ ./out
Hello world!
$ gdb out
GNU gdb (Ubuntu 9.2-0ubuntu1~20.04) 9.2
...
Reading symbols from out...
(gdb) b _start
Breakpoint 1 at 0x10074: file hello.s, line 4.
(gdb) run
Starting program: /home/ubuntu/280/out
```
At this point everything hangs until I press ^C:
```
^C
Program received signal SIGINT, Interrupt.
0x0000aaaaba072284 in ?? ()
(gdb) bt
#0 0x0000aaaaba072284 in ?? ()
#1 0x0000000000007232 in ?? ()
Backtrace stopped: previous frame identical to this frame (corrupt stack?)
(gdb) l
1 .text
2 .global _start
3 _start:
4 MOV R7, #4
5 MOV R0, #1
6 LDR R1, =hello
7 LDR R2, =hello_size
8 SWI 0
9 MOV R7, #1
10 SWI 0
(gdb) q
A debugging session is active.
Inferior 1 [process 29234] will be killed.
Quit anyway? (y or n) y
$
```
It appears that gdb generally works and recognizes the executable, but
breakpoints don't work. I'm new at Arm and don't have a lot of
experience with assembly (at least not since the early 1970s), so it
could easily be my problem but it seems suspiciously like an earlier
problem and I think what I've done should work.
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/gdb/+bug/1901966/+subscriptions
More information about the foundations-bugs
mailing list