gdb - Remote 'g' packet reply is too long

Question

I am trying to debug Linux kernel with kvm vm. I am getting an error message "Remote 'g' packet reply is too long". My host is 64-bit and so is my vm.

My steps:

1. Start the VM with custom -kernel, -initrd and -append options.
2. Start gdb
3. Execute "set architecture i386:x86-64:intel"
4. Execute "add-symbol-file linux-3.0/vmlinux"
5. Execute "show arch" to verify its still "i386:x86-64:intel"
6. Execute "target remote localhost:1234"
7. Execute "continue"
8. Press Ctrl+C, I get the above message.

Has anyone faced this problem?

Answer 1

gdb doesn't work well against a cpu that switches between instruction sets at runtime. Wait for the kernel to leave early boot before connecting, and don't use qemu's -S flag.