guest patched with pax causes "set_cr0: 0xffff88000[...] #GP, reserved bits 0x8004003?" flood on host
Hi,
I've updated my host kernel headers to 2.6.33, rebuilt glibc (and the base system), rebuilt kvm.
... and now I get hundreds of those in dmesg on the host when I start a guest kernel that worked fine before. (2.6.33 + pax patch v5)
set_cr0: 0xffff88000ec29d58 #GP, reserved bits 0x80040033
set_cr0: 0xffff88000f3cdb38 #GP, reserved bits 0x8004003b
set_cr0: 0xffff88000f3dbc88 #GP, reserved bits 0x80040033
set_cr0: 0xffff88000f83b958 #GP, reserved bits 0x8004003b
(hundreds of all 4)
And the VM just reboots shortly after starting init.
Funnily enough, I've got some VMs still running that kernel just fine! (as I started them before the headers+glibc+qemu-kvm rebuild)
Now, you might just say that I shouldn't use out of tree patches like pax, but I just want to know one thing: should the guest kernel still be able to flood dmesg on the host like this?
Thanks
Antoine
PS: Avi, are you still interested in seeing if this rebuild fixes the pread/glibc bug?
Quoted 8 lines · Antoine Martin
Hi,
I've updated my host kernel headers to 2.6.33, rebuilt glibc (and the base system), rebuilt kvm.
... and now I get hundreds of those in dmesg on the host when I start a guest kernel that worked fine before. (2.6.33 + pax patch v5)
set_cr0:0xffff88000ec29d58#GP, reserved bits0x80040033
set_cr0:0xffff88000f3cdb38#GP, reserved bits0x8004003b
set_cr0:0xffff88000f3dbc88#GP, reserved bits0x80040033
set_cr0:0xffff88000f83b958#GP, reserved bits0x8004003b
The guest is clearly confused. Can you bisect kvm to find out what introduced this problem?
Quoted 5 lines
(hundreds of all 4)
And the VM just reboots shortly after starting init.
Funnily enough, I've got some VMs still running that kernel just fine! (as I started them before the headers+glibc+qemu-kvm rebuild)Now, you might just say that I shouldn't use out of tree patches like pax,
You can run anything you like in a guest.
Quoted 1 line
but I just want to know one thing: should the guest kernel still be able to flood dmesg on the host like this?
No, these are debug messages.
Quoted 5 lines
Thanks
AntoinePS: Avi, are you still interested in seeing if this rebuild fixes the pread/glibc bug?
I think we figured it out, but a confirmation would be nice.
Signature · 1 line
error compiling committee.c: too many arguments to function
Quoted 12 lines · Avi Kivity
Quoted 10 lines · Antoine Martin
Hi,
I've updated my host kernel headers to 2.6.33, rebuilt glibc (and the base system), rebuilt kvm.
... and now I get hundreds of those in dmesg on the host when I start a guest kernel that worked fine before. (2.6.33 + pax patch v5)
set_cr0:0xffff88000ec29d58#GP, reserved bits0x80040033
set_cr0:0xffff88000f3cdb38#GP, reserved bits0x8004003b
set_cr0:0xffff88000f3dbc88#GP, reserved bits0x80040033
set_cr0:0xffff88000f83b958#GP, reserved bits0x8004003b
Quoted 2 lines
The guest is clearly confused. Can you bisect kvm to find out what introduced this problem?
the guest is calling pax_{open,close}_kernel that flip cr0.wp off/on, respectively. Antoine, can you decode some of those rip values please (or better, send me the corresponding vmlinux and all logs)?
Quoted 16 lines · On 03/11/2010 04:31 PM, [email protected] wrote:
Quoted 13 lines · Avi Kivity
Quoted 11 lines · Antoine Martin
Hi,
I've updated my host kernel headers to 2.6.33, rebuilt glibc (and the base system), rebuilt kvm.
... and now I get hundreds of those in dmesg on the host when I start a guest kernel that worked fine before. (2.6.33 + pax patch v5)
set_cr0:0xffff88000ec29d58#GP, reserved bits0x80040033
set_cr0:0xffff88000f3cdb38#GP, reserved bits0x8004003b
set_cr0:0xffff88000f3dbc88#GP, reserved bits0x80040033
set_cr0:0xffff88000f83b958#GP, reserved bits0x8004003b
Quoted 3 lines
Quoted 3 lines
The guest is clearly confused. Can you bisect kvm to find out what introduced this problem?
OK, will try to find the time.
Quoted 3 lines
the guest is calling pax_{open,close}_kernel that flip cr0.wp off/on, respectively. Antoine, can you decode some of those rip values please (or better, send me the corresponding vmlinux and all logs)
I've dumped everything here (.config, vmlinuz and log):
http://users.nagafix.co.uk/~antoine/KVM/
Antoine
Quoted 12 lines · Avi Kivity
Quoted 10 lines · Antoine Martin
Hi,
I've updated my host kernel headers to 2.6.33, rebuilt glibc (and the base system), rebuilt kvm.
... and now I get hundreds of those in dmesg on the host when I start a guest kernel that worked fine before. (2.6.33 + pax patch v5)
set_cr0:0xffff88000ec29d58#GP, reserved bits0x80040033
set_cr0:0xffff88000f3cdb38#GP, reserved bits0x8004003b
set_cr0:0xffff88000f3dbc88#GP, reserved bits0x80040033
set_cr0:0xffff88000f83b958#GP, reserved bits0x8004003b
Quoted 2 lines
The guest is clearly confused. Can you bisect kvm to find out what introduced this problem?
i screwed up the paravirt register clobbers, don't worry about it.