Re: Using ubuntu24.4 system qemu-system-aarch64 +gdb-multiarch to debug the kernel, setting breakpoints cannot be stopped

Thank you very much. Adding kaslr successfully solved the problem.

Ilya Leoshkevich <[email protected]> 于2024年9月24日周二 00:34写道：

> On Mon, 2024-09-23 at 22:36 +0800, jie ren wrote:
> > Hi, I have a question for help
> >     I recently  Using ubuntu24.4 system qemu-system-aarch64 +gdb-
> > multiarch to debug the kernel, setting breakpoints cannot be stopped.
> >    system information:
> >         ubuntu version: 22.04
> >         Debug kernel version:  5.0.0
> >         qemu version:
> > · qemu-system-aarch64 --version
> > · QEMU emulator version 8.2.2 (Debian 1:8.2.2+ds-0ubuntu1.2)
> > · Copyright (c) 2003-2023 Fabrice Bellard and the QEMU Project
> > developers
> >
> >
> >
> > gdb version:
> > · gdb-multiarch --version
> > · GNU gdb (Ubuntu 15.0.50.20240403-0ubuntu1) 15.0.50.20240403-git
> > · Copyright (C) 2024 Free Software Foundation, Inc.
> > · License GPLv3+: GNU GPL version 3 or later
> > <http://gnu.org/licenses/gpl.html>
> > · This is free software: you are free to change and redistribute it.
> > · There is NO WARRANTY, to the extent permitted by law.
> >
> > Steps to reproduce:
> >     1. Boot the system using qemu:
> > 1. qemu-system-aarch64 -machine virt -cpu cortex-a57 -machine
> > type=virt -m 1024 -smp 4 -kernel arch/arm64/boot/Image --append
> > "noinitrd root=/dev/vda rw console=ttyAMA0 loglevel=8" -nographic -
> > drive if=none,file=rootfs_ext4.img,id=hd0 -device virtio-blk-
> > device,drive=hd0 --fsdev
> > local,id=kmod_dev,path=$PWD/kmodules,security_model=none -device
> > virtio-9p-device,fsdev=kmod_dev,mount_tag=kmod_mount -S -s
> >
> >
> > Use gdb-multiarch to connect and debug:
> >
> >
> > gdb-multiarch vmlinux
> > (gdb) target remote localhost:1234
> > Remote debugging using localhost:1234
> > 0x0000000040000000 in ?? ()
> > (gdb) b start_kernel
> > Breakpoint 1 at 0xffff2000126704ec: file init/main.c, line 538.
> > (gdb) c
> > Continuing.
>
> I would try using the "nokaslr" kernel option:
>
> $ qemu-system-aarch64 -kernel ./Image.custom -M virt -cpu cortex-a57 -
> append "console=ttyAMA0 nokaslr" -s -S -nographic
>
> $ gdb-multiarch -ex 'target remote :1234' vmlinux
>
> Remote debugging using :1234
> 0x0000000040000000 in ?? ()
> (gdb) b start_kernel
> Breakpoint 1 at 0xffff8000811e0968: file init/main.c, line 905.
> (gdb) c
> Continuing.
>
> Breakpoint 1, start_kernel () at init/main.c:905
> 905             char *command_line;
>
>