Hi guys, any update on this? Just to be sure, I tried to the Linux kernel 4.19.16 in the same scenario and I got the same result. I built the kernel with buildroot and I launched QEMU with:
qemu-system-i386 -kernel bzImage -S -s -append 'nokaslr' I know it needs an initrd and a hdd img in order to boot a full system, but for me it was enough to break on start_kernel and then trying to do `stepi`. Exactly like with the other project, with the gdb version `Ubuntu 8.1-0ubuntu3` it worked perfectly, while with gdb `Ubuntu 8.1-0ubuntu3.1` I got the same problem: (gdb) b start_kernel warning: Breakpoint address adjusted from 0xc17257cd to 0xffffffffc17257cd. Breakpoint 1 at 0xc17257cd (gdb) c Continuing. Program received signal SIGTRAP, Trace/breakpoint trap. 0xc17257cd in start_kernel () (gdb) si 0xc17257cd in start_kernel () (gdb) si 0xc17257cd in start_kernel () (gdb) si 0xc17257cd in start_kernel () (gdb) si Therefore, as expected, the bug affects _definitively_ any kind of 32-bit code when remote debugging is used and the client is 64-bit. I also checked if the latest non-Ubuntu gdb is affected by this issue and it's not. In conclusion, I believe that the following patch introduced the regression: http://launchpadlibrarian.net/431301516/gdb_8.1-0ubuntu3_8.1-0ubuntu3.1.diff.gz And that the bug needs to get some attention. After all, people _cannot_ debug a 32-bit linux kernel running on a VM anymore, if they're using Ubuntu. @Manoj could you please comment? Thanks -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1846557 Title: Unable to debug any kernel on i386 qemu machine To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gdb/+bug/1846557/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
