Re: __unlazy_fpu with Sandy Bridge?

[Keir Fraser <keir.xen@gmail.com>]

On 27/04/2011 03:58, "Konrad Rzeszutek Wilk" <konrad.wilk@oracle.com> wrote:

> On Tue, Apr 26, 2011 at 09:57:58PM -0400, Konrad Rzeszutek Wilk wrote:
>> I bought over the weekend a Sandy Bridge machine and quite often
>> when I launch a guest I get this:
> 
> Which disappear if I do 'xsave=0'. Looks like there is still some lingering
> bug?
> (I did build it with the patch that Keir posted).

I may have plumbed the XSAVE CPUID stuff incorrecty for PV guests. Intel
probably need to take a look.

 -- Keir

>> 
>> [    1.519320] modprobe used greatest stack depth: 6348 bytes left
>> [    1.528966] udevd (1158): /proc/1158/oom_adj is deprecated, please use
>> /proc/1158/oom_score_adj instead.
>> 
>> [    1.610819] BUG: unable to handle kernel paging request at cb5b007f
>> [    1.610839] IP: [<c102b88a>] __unlazy_fpu+0x20/0x84
>> [    1.610854] *pdpt = 000000000b49f027 *pde = 000000000c0b1067 *pte =
>> 800000000b5b0061
>> [    1.610874] Oops: 0003 [#1] SMP
>> [    1.610886] last sysfs file: /sys/devices/virtual/tty/ptyp9/uevent
>> [    1.610896] Modules linked in: xen_blkfront xen_netfront xen_fbfront
>> fb_sys_fops sysimgblt sysfillrect syscopyarea xen_kbdfront xenfs
>> [    1.610934] 
>> [    1.610941] Pid: 1424, comm: ifup Not tainted
>> 2.6.39-rc4yes_xen_blkdev-00489-gfa5424e #1
>> [    1.610959] EIP: 0061:[<c102b88a>] EFLAGS: 00010086 CPU: 1
>> [    1.610969] EIP is at __unlazy_fpu+0x20/0x84
>> [    1.610977] EAX: ffffffff EBX: ead8c4e0 ECX: cb602700 EDX: ffffffff
>> [    1.610987] ESI: eb3d3180 EDI: cb5afd40 EBP: cb60de60 ESP: cb60de5c
>> [    1.610997]  DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0069
>> [    1.611007] Process ifup (pid: 1424, ti=cb60c000 task=cb602700
>> task.ti=cb5c8000)
>> [    1.611017] Stack:
>> [    1.611023]  cb602700 cb60de88 c102b938 ead8c4e0 eb3d5480 0060224c
>> 00000001 eb3d5480
>> [    1.611055]  cb4adc00 eb3d5480 ead8c4e0 cb5c9f50 c13d45ce cb60df1c
>> 00000282 5fb55ce4
>> [    1.611055]  00000000 c15e7480 ead8c4e0 c15e7480 c15e7480 ead8c758
>> cb60df1c c15e7480
>> [    1.611055] Call Trace:
>> [    1.611055]  [<c102b938>] __switch_to+0x40/0xfa
>> [    1.611055]  [<c13d45ce>] schedule+0x5fb/0x667
>> [    1.611055]  [<c1029d43>] ? xen_restore_fl_direct_reloc+0x4/0x4
>> [    1.611055]  [<c10c4b05>] ? free_hot_cold_page+0xf8/0x100
>> [    1.611055]  [<c102a21c>] ? get_phys_to_machine+0x18/0x4c
>> [    1.611055]  [<c10296cf>] ? xen_force_evtchn_callback+0xf/0x14
>> [    1.611055]  [<c1029d4c>] ? check_events+0x8/0xc
>> [    1.611055]  [<c1029d43>] ? xen_restore_fl_direct_reloc+0x4/0x4
>> [    1.611055]  [<c13d5792>] ? _raw_spin_unlock_irqrestore+0x14/0x17
>> [    1.611055]  [<c1074a7f>] ? add_wait_queue+0x30/0x35
>> [    1.611055]  [<c1061112>] ? do_wait+0x183/0x1e1
>> [    1.611055]  [<c10611f8>] ? sys_wait4+0x88/0xa1
>> [    1.611055]  [<c105fa70>] ? wait_noreap_copyout+0xdf/0xdf
>> [    1.611055]  [<c1061224>] ? sys_waitpid+0x13/0x15
>> [    1.611055]  [<c13daa98>] ? sysenter_do_call+0x12/0x28
>> [    1.611055] Code: 31 ff 5a 89 f8 59 5b 5e 5f 5d c3 55 89 c1 89 e5 57 8b 40
>> 04 f6 40 0c 01 74 6b b0 01 84 c0 74 1f 83 c8 ff 8b b9 38 03 00 00 89 c2 <0f>
>> ae 37 8b 81 38 03 00 00 f6 80 00 02 00 00 01 75 18 eb 2e b0
>> [    1.611055] EIP: [<c102b88a>] __unlazy_fpu+0x20/0x84 SS:ESP 0069:cb60de5c
>> [    1.611055] CR2: 00000000cb5b007f
>> [    1.611055] ---[ end trace 0e00f93ab96a1012 ]---
>> [    1.611055] Fixing recursive fault but reboot is needed!
>> 
>> 
>> Has anybody seen something similar to this?
>> 
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