Re: [Xen-devel] [BUG] Xen vm kernel crash in get_free_entries.

[Sander Eikelenboom <linux@xxxxxxxxxxxxxx>]

Wednesday, November 27, 2013, 12:05:01 AM, you wrote:

> Sander Eikelenboom <linux@xxxxxxxxxxxxxx> wrote:
>>
>>Tuesday, November 26, 2013, 11:00:15 PM, you wrote:
>>
>>
>>> Tuesday, November 26, 2013, 9:08:47 PM, you wrote:
>>
>>>> On Wed, Nov 13, 2013 at 09:40:58AM +0000, Ian Campbell wrote:
>>>>> On Tue, 2013-11-12 at 10:56 -0500, Konrad Rzeszutek Wilk wrote:
>>>>> > On Thu, Nov 07, 2013 at 01:47:03PM +0000, Ian Campbell wrote:
>>>>> > > On Thu, 2013-11-07 at 09:20 +0400, Astarta wrote:
>>>>> > > > Hello,
>>>>> > > > 
>>>>> > > > Let me bring some new life to this discussion.
>>>>> > > > 
>>>>> > > > I've investigated a bit and found another way to make 
>>kernels starting 
>>>>> > > > from 3.8.x to boot on the VMs with platform device_id 0002.
>>>>> > > > Reverting of
>>xen-grant-table-correctly-initialize-grant-table-version-1 
>>>>> > > > patch is not necessary.
>>>>> > > > 
>>>>> > > > We can simply modify struct pci_device_id platform_pci_tbl[]
>>(in 
>>>>> > > > drivers/xen/platform-pci.c) to respect 0002 and 0000 device
>>ids.
>>>>> > > > That makes the kernel (3.8.x and 3.11.6) to boot correctly,
>>disks and 
>>>>> > > > network are also recognized.
>>>>> > > 
>>>>> > > I think this is just working around the problem, by avoiding
>>the
>>>>> > > situation where the error occurs. You could just as well switch
>>to
>>>>> > > platform device id < 2.
>>>>> > 
>>>>> > I am bit late to this discussion - but shouldn't there be
>>something
>>>>> > in the kernel to deal with this?
>>>>> 
>>>>> Well, ideally the kernel wouldn't crash ;-)
>>
>>>> This patch should solve that (untested, but at least compile
>>tested):
>>>> Please test it.
>>
>>> Hi Konrad,
>>
>>> I just gave it a shot on qemu-xen-traditional (since support for
>>xen_platform_pci=0 is not upstream (yet))
>>> It doesn't crash anymore on boot, but the guest now doesn't have any
>>disks, so it ends in busybox because it can't find a root partition.
>>> I would have expected it to be using qemu emulated disks now, but a
>>"cat /proc/partitions" in busybox shows nothing.
>>> But that's perhaps qemu code ejecting the emulated disks anyhow ...
>>
>>Hi Konrad,
>>
>>With the linux PATA modules compiled in it now also boots fine with
>>qemu-xen-traditional and xen_platform_pci=0

> Wohoooo! I will be tack on Tested and Reported by tag on it.

> Thank you for quick testing!

Thanks , don't know if you want to consider it for stable as well, seems to be 
since the 3.8 series ..

--
Sander

>>
>>Thanks,
>>
>>Sander
>>
>>> In the config file i use:
>>>  disk = [ 'phy:/dev/xen_vms/testvm,hda,w' ]
>>
>>> --
>>> Sander
>>
>>>> From f7d3581aa19a35ea3ff10b965b2b08843e923635 Mon Sep 17 00:00:00
>>2001
>>>> From: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
>>>> Date: Tue, 26 Nov 2013 15:05:40 -0500
>>>> Subject: [PATCH] xen/pvhvm: If xen_platform_pci=0 is set don't blow
>>up.
>>
>>>> *TODO*
>>
>>>> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
>>>> ---
>>>>  drivers/block/xen-blkfront.c               |  2 +-
>>>>  drivers/input/misc/xen-kbdfront.c          |  4 ++++
>>>>  drivers/net/xen-netfront.c                 |  2 +-
>>>>  drivers/xen/xenbus/xenbus_probe_frontend.c |  2 +-
>>>>  include/xen/platform_pci.h                 | 13 +++++++++++++
>>>>  5 files changed, 20 insertions(+), 3 deletions(-)
>>
>>>> diff --git a/drivers/block/xen-blkfront.c
>>b/drivers/block/xen-blkfront.c
>>>> index 432db1b..bcbaf0b 100644
>>>> --- a/drivers/block/xen-blkfront.c
>>>> +++ b/drivers/block/xen-blkfront.c
>>>> @@ -2074,7 +2074,7 @@ static int __init xlblk_init(void)
>>>>         if (!xen_domain())
>>>>                 return -ENODEV;
>>>>  
>>>> -       if (xen_hvm_domain() && !xen_platform_pci_unplug)
>>>> +       if (xen_err_out())
>>>>                 return -ENODEV;
>>>>  
>>>>         if (register_blkdev(XENVBD_MAJOR, DEV_NAME)) {
>>>> diff --git a/drivers/input/misc/xen-kbdfront.c
>>b/drivers/input/misc/xen-kbdfront.c
>>>> index e21c181..9d250cf 100644
>>>> --- a/drivers/input/misc/xen-kbdfront.c
>>>> +++ b/drivers/input/misc/xen-kbdfront.c
>>>> @@ -29,6 +29,7 @@
>>>>  #include <xen/interface/io/fbif.h>
>>>>  #include <xen/interface/io/kbdif.h>
>>>>  #include <xen/xenbus.h>
>>>> +#include <xen/platform_pci.h>
>>>>  
>>>>  struct xenkbd_info {
>>>>         struct input_dev *kbd;
>>>> @@ -380,6 +381,9 @@ static int __init xenkbd_init(void)
>>>>         if (xen_initial_domain())
>>>>                 return -ENODEV;
>>>>  
>>>> +       if (xen_err_out())
>>>> +               return -ENODEV;
>>>> +
>>>>         return xenbus_register_frontend(&xenkbd_driver);
>>>>  }
>>>>  
>>>> diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
>>>> index e59acb1..be2744b 100644
>>>> --- a/drivers/net/xen-netfront.c
>>>> +++ b/drivers/net/xen-netfront.c
>>>> @@ -2115,7 +2115,7 @@ static int __init netif_init(void)
>>>>         if (!xen_domain())
>>>>                 return -ENODEV;
>>>>  
>>>> -       if (xen_hvm_domain() && !xen_platform_pci_unplug)
>>>> +       if (xen_err_out())
>>>>                 return -ENODEV;
>>>>  
>>>>         pr_info("Initialising Xen virtual ethernet driver\n");
>>>> diff --git a/drivers/xen/xenbus/xenbus_probe_frontend.c
>>b/drivers/xen/xenbus/xenbus_probe_frontend.c
>>>> index 129bf84..b1c0f2a 100644
>>>> --- a/drivers/xen/xenbus/xenbus_probe_frontend.c
>>>> +++ b/drivers/xen/xenbus/xenbus_probe_frontend.c
>>>> @@ -496,7 +496,7 @@ subsys_initcall(xenbus_probe_frontend_init);
>>>>  #ifndef MODULE
>>>>  static int __init boot_wait_for_devices(void)
>>>>  {
>>>> -       if (xen_hvm_domain() && !xen_platform_pci_unplug)
>>>> +       if (xen_err_out())
>>>>                 return -ENODEV;
>>>>  
>>>>         ready_to_wait_for_devices = 1;
>>>> diff --git a/include/xen/platform_pci.h b/include/xen/platform_pci.h
>>>> index 438c256..a5bbd0b 100644
>>>> --- a/include/xen/platform_pci.h
>>>> +++ b/include/xen/platform_pci.h
>>>> @@ -47,5 +47,18 @@ static inline int xen_must_unplug_disks(void) {
>>>>  }
>>>>  
>>>>  extern int xen_platform_pci_unplug;
>>>> +static  bool xen_err_out(void)
>>>> +{
>>>>  
>>>> +       if (!xen_domain())
>>>> +               return true;
>>>> +
>>>> +       if (xen_hvm_domain()) {
>>>> +               if (xen_platform_pci_unplug &
>>(XEN_UNPLUG_UNNECESSARY | XEN_UNPLUG_NEVER))
>>>> +                       return true;
>>>> +               if (xen_platform_pci_unplug == 0)
>>>> +                       return true;
>>>> +       }
>>>> +       return false;
>>>> +}
>>>>  #endif /* _XEN_PLATFORM_PCI_H */





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