Re: kvm: unable to handle kernel NULL pointer dereference

Chris Wright
2008-06-05T07:27:36Z

* Tobias Diedrich (ranma+kernel@tdiedrich.de) wrote:
> Almost:
> ranma@melchior:~/src/linux-2.6.26-rc4.forcedwol$ gdb -q vmlinux
> Using host libthread_db library "/lib/libthread_db.so.1".
> (gdb) p/x 0xffffffff8021d456 + 0x6f9cba
> $1 = 0xffffffff80917110
> (gdb) p/x &per_cpu__svm_data
> $2 = 0xffffffff809170f8
> (gdb)

Sorry, my math was bad. I gave you 0xffffffff8021d44f + 7 + 0x6f9cba,
but it should have been 0xffffffff8021d44f - 17 + 0x6f9cba. Which is
correct (as one would hope, it was a grasp at straws).

Oh, wait. Is this a laptop? Do you suspend/resume? Suspend will free
svm_data, and on resume, any launching a guest will definitely hit the
oops you are seeing.

Do you ever see this in dmesg?

svm_cpu_init: svm_data is NULL on 0

thanks,
chris