On Sat, Jun 9, 2012 at 8:01 PM, Adam Lee <adam8157@gmail.com> wrote:
On Sat, Jun 09, 2012 at 04:19:15PM +0600, Aft nix wrote:
Thank you for the tips. qemu is booting the kernel now. But it stops with a kernel panic.
From qemu console,
[ 2.209887] EXT3-fs (sda): mounted filesystem with writeback data mode [ 2.210566] VFS: Mounted root (ext3 filesystem) readonly on device 8:0. [ 2.211393] Freeing unused kernel memory: 456k freed [ 2.242325] Write protecting the kernel text: 6240k [ 2.242614] Write protecting the kernel read-only data: 1820k [ 2.248007] Kernel panic - not syncing: No init found. Try passing init= option to kernel. See Linux Documentation/init.txt for guidance. [ 2.248492] Pid: 1, comm: swapper/0 Not tainted 3.4.0+ #3 [ 2.248596] Call Trace: [ 2.249743] [<c160db4f>] panic+0x81/0x17e [ 2.249843] [<c10012d5>] init_post+0x75/0xb0 [ 2.249942] [<c183a61a>] kernel_init+0x1e0/0x1ea [ 2.250028] [<c183a3df>] ? parse_early_options+0x35/0x35 [ 2.250237] [<c183a43a>] ? repair_env_string+0x5b/0x5b [ 2.250326] [<c1616cd6>] kernel_thread_helper+0x6/0xd ... My understanding is i have to put the init binary in my root fs. But i'm clueless about how to do that?
You need a full system, kernel is just the core.
I suggest you using Debian stable images for QEMU at http://people.debian.org/~aurel32/qemu (ref: http://wiki.debian.org/QEMU)
Or, use busybox to build rootfs like what I am doing: https://github.com/adam8157/kernel-studio
Hi Adam Thanks for the reply. Googling revealed other ways of debugging. I was not aware that KGDB was merged with linux in 2.6.26. I was under the impression that Linux does not allow kernel debugger in kernel source tree. If i compile a kernel with KGDB , and if i'm not developing for "other" archs like ppc/arm then there is little gain in qemu's gdb stub. Instead i can fire up a full distro in Virtualbox, configure a virtual serial console and "socat" from the host. This link : http://www.linuxforu.com/2011/03/kgdb-with-virtualbox-debug-live-kernel/ I'm trying to follow this link instead. I'm not experienced in this field, so my reasoning might be wrong. If it is, please comment on my approach. Cheers.
-- Regards, Adam Lee -------------------------------- E-mail: adam8157@gmail.com Website: http://adam8157.info --------------------------------
-- -aft