Re: [x86, kaslr] BUG: kernel early hang without any printk output

From: Kees Cook
Date: Tue Oct 08 2013 - 01:31:57 EST


On Mon, Oct 7, 2013 at 9:47 PM, Fengguang Wu <fengguang.wu@xxxxxxxxx> wrote:
> Greetings,
>
> I got the below dmesg and the first bad commit is
>
> commit 10fe632a9c6b9ade004c8b0c2ea2c3c562d24f18
> Author: Kees Cook <keescook@xxxxxxxxxxxx>
> Date: Thu Apr 25 14:20:25 2013 -0700
>
> x86, kaslr: find minimum safe relocation position
>
> Examine all the known unsafe areas and avoid them by just raising the
> minimum relocation position to be past them.
>
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
>
> Command line: hung_task_panic=1 rcutree.rcu_cpu_stall_timeout=100 log_buf_len=8M ignore_loglevel debug sched_debug apic=debug dynamic_printk sysrq_always_enabled panic=10 prompt_ramdisk=0 console=ttyS0,115200 console=tty0 vga=normal root=/dev/ram0 rw link=/kernel-tests/run-queue/kvm/i386-randconfig-i005-1008/kees:kaslr-c-v6/.vmlinuz-544c3c7c7c7a22deabefbdd4b42675924bcc7afa-20131008114452-8-inn branch=kees/kaslr-c-v6 BOOT_IMAGE=/kernel/i386-randconfig-i005-1008/544c3c7c7c7a22deabefbdd4b42675924bcc7afa/vmlinuz-3.12.0-rc4-00027-g544c3c7

Thanks! Yeah, the -v6 of this series had some problems. I've removed
the old versions from my tree now. -v8 should behave better, though
it's still being worked on.

-Kees

--
Kees Cook
Chrome OS Security
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