I've been able to reproduce the problem on 32-bit Ubuntu 20.04 for RPi4. The problem reproduces when the following is linked:
ld-linux-armhf.so.3 -> ld-2.31.so* fostja@cptr280-arm:~/code/asm$ gdb -q hello GEF for linux ready, type `gef' to start, `gef config' to configure 75 commands loaded for GDB 9.2 using Python engine 3.8 [*] 5 commands could not be loaded, run `gef missing` to know why. Reading symbols from hello... gef➤ set debug infrun 1 gef➤ b _start Breakpoint 1 at 0x1016c: file hello.s, line 5. gef➤ start infrun: infrun_async(1) infrun: proceed (addr=0xb6fd5a80, signal=GDB_SIGNAL_0) infrun: proceed: resuming process 10100 infrun: resume (step=0, signal=GDB_SIGNAL_0), trap_expected=0, current thread [process 10100] at 0xb6fd5a80 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 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 When I revert to the following then things work properly: ld-linux-armhf.so.3 -> ld-2.28.so* So I have a work-around. It appears that the problem was introduced between 2.28 and 2.31. -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, 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: New 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 -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
