diff options
Diffstat (limited to 'gitlab/issues_text/target_missing/host_missing/accel_KVM/1274')
| -rw-r--r-- | gitlab/issues_text/target_missing/host_missing/accel_KVM/1274 | 32 |
1 files changed, 0 insertions, 32 deletions
diff --git a/gitlab/issues_text/target_missing/host_missing/accel_KVM/1274 b/gitlab/issues_text/target_missing/host_missing/accel_KVM/1274 deleted file mode 100644 index 5ab368da0..000000000 --- a/gitlab/issues_text/target_missing/host_missing/accel_KVM/1274 +++ /dev/null @@ -1,32 +0,0 @@ -Cannot debug init using "qemu -s -S" if init is compiled dynamically or if kvm is enabled -Description of problem: -I'm trying to connect from host to init process running in guest. I'm using this guide: https://qemu-project.gitlab.io/qemu/system/gdb.html . Everything works well, but there is two problems: -1. Debugging stops to work if I add "-enable-kvm" -2. Debugging stops to work if I remove "-static" when compiling init -Steps to reproduce: -I have absolutely fresh Debian sid system (as of 2022-10-22). I create the following file on it: -```c -#include <stdio.h> - -int -main () -{ - printf ("a\n"); - printf ("b\n"); - for (;;); -} -``` - -Then I compile it so: `gcc -static -g a.c`. Result is saved as `/root/a.out`. Then I run `sync; echo 3 > /proc/sys/vm/drop_caches; sync` to make sure this `/root/a.out` actually got to disk. - -Then I start the host system inside of qemu using well-known `-snapshot /dev/sda` trick. Exact command is here: - -```bash -qemu-system-x86_64 -daemonize -m 300M -s -S -kernel /vmlinuz -initrd /initrd.img -snapshot -append "root=/dev/sda init=/root/a.out" -drive file=/dev/sda,format=raw -``` - -(As you guessed, my disk has no partitions, it directly stores ext4 filesystem.) - -Then I type on host `gdb ./a.out`. And then inside of gdb I type `target remote localhost:1234`, then `br 7` (line 7 is `printf ("b\n")`, then `c`. Then guest OS boots and reaches init (i. e. `/root/a.out`). And then gdb actually pauses on line 7. I. e. everything works! - -But if I add `-enable-kvm` to qemu command line OR remove `-static` from gcc command line, then breakpoint doesn't work, i. e. gdb doesn't pause on breakpoint, the execution continues and the execution fails to infinite loop. |