xen-netback fixes for stable 35876b5 3e55f8b

xen-netback fixes for stable 35876b5 3e55f8b

[William Dauchy]

[-- Attachment #1: Type: text/plain, Size: 2851 bytes --]

Hello,

I believe the two commits 35876b5 and 3e55f8b could be included in stable tree.
35876b5 is related to 4885628 already in the stable tree and fixes a
possible oops.
3e55f8b is fixing another possible oops (see commit messages).

I tested them on top of a v3.4.33.
Could we consider adding these patches in stable tree at least for v3.4?

Tested-by: William Dauchy <william@gandi.net>
Cc: stable@vger.kernel.org



commit 35876b5ffc154c357476b2c3bdab10feaf4bd8f0
Author: David Vrabel <david.vrabel@citrix.com>
Date:   Thu Feb 14 03:18:57 2013 +0000

    xen-netback: correctly return errors from netbk_count_requests()
   
    netbk_count_requests() could detect an error, call
    netbk_fatal_tx_error() but return 0.  The vif may then be used
    afterwards (e.g., in a call to netbk_tx_error().
   
    Since netbk_fatal_tx_error() could set vif->refcnt to 1, the vif may
    be freed immediately after the call to netbk_fatal_tx_error() (e.g.,
    if the vif is also removed).
   
    Netback thread              Xenwatch thread
    -------------------------------------------
    netbk_fatal_tx_err()        netback_remove()
                                  xenvif_disconnect()
                                    ...
                                    free_netdev()
    netbk_tx_err() Oops!
   
    Signed-off-by: Wei Liu <wei.liu2@citrix.com>
    Signed-off-by: Jan Beulich <JBeulich@suse.com>
    Signed-off-by: David Vrabel <david.vrabel@citrix.com>
    Reported-by: Christopher S. Aker <caker@theshore.net>
    Acked-by: Ian Campbell <ian.campbell@citrix.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>

commit 3e55f8b306cf305832a4ac78aa82e1b40e818ece
Author: David Vrabel <david.vrabel@citrix.com>
Date:   Thu Feb 14 03:18:58 2013 +0000

    xen-netback: cancel the credit timer when taking the vif down
   
    If the credit timer is left armed after calling
    xen_netbk_remove_xenvif(), then it may fire and attempt to schedule
    the vif which will then oops as vif->netbk == NULL.
   
    This may happen both in the fatal error path and during normal
    disconnection from the front end.
   
    The sequencing during shutdown is critical to ensure that: a)
    vif->netbk doesn't become unexpectedly NULL; and b) the net device/vif
    is not freed.
   
    1. Mark as unschedulable (netif_carrier_off()).
    2. Synchronously cancel the timer.
    3. Remove the vif from the schedule list.
    4. Remove it from it netback thread group.
    5. Wait for vif->refcnt to become 0.
   
    Signed-off-by: David Vrabel <david.vrabel@citrix.com>
    Acked-by: Ian Campbell <ian.campbell@citrix.com>
    Reported-by: Christopher S. Aker <caker@theshore.net>
    Signed-off-by: David S. Miller <davem@davemloft.net>


Regards,
-- 
William

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 198 bytes --]

Re: xen-netback fixes for stable 35876b5 3e55f8b

[Greg Kroah-Hartman]

On Fri, Feb 22, 2013 at 05:47:28PM +0100, William Dauchy wrote:
> Hello,
> 
> I believe the two commits 35876b5 and 3e55f8b could be included in stable tree.
> 35876b5 is related to 4885628 already in the stable tree and fixes a
> possible oops.
> 3e55f8b is fixing another possible oops (see commit messages).
> 
> I tested them on top of a v3.4.33.
> Could we consider adding these patches in stable tree at least for v3.4?

You mean 3.4 and newer, right?

Are you sure that 3.2 and 3.0 aren't also relevant here?

thanks,

greg k-h

Re: xen-netback fixes for stable 35876b5 3e55f8b

[William Dauchy]

[-- Attachment #1: Type: text/plain, Size: 246 bytes --]

On Feb22 09:08, Greg Kroah-Hartman wrote:
> You mean 3.4 and newer, right?
> Are you sure that 3.2 and 3.0 aren't also relevant here?

They are, but didn't test them directly.
I just applied them without trouble.

Thanks,

-- 
William

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 198 bytes --]

Re: xen-netback fixes for stable 35876b5 3e55f8b

[Greg Kroah-Hartman]

On Fri, Feb 22, 2013 at 06:17:54PM +0100, William Dauchy wrote:
> On Feb22 09:08, Greg Kroah-Hartman wrote:
> > You mean 3.4 and newer, right?
> > Are you sure that 3.2 and 3.0 aren't also relevant here?
> 
> They are, but didn't test them directly.
> I just applied them without trouble.

What does that mean?  Should they be applied for those kernels or not?

confused,

greg k-h

Re: xen-netback fixes for stable 35876b5 3e55f8b

[William Dauchy]

[-- Attachment #1: Type: text/plain, Size: 188 bytes --]

On Feb22 09:28, Greg Kroah-Hartman wrote:
> What does that mean?  Should they be applied for those kernels or not?

Yes indeed.
Sorry for my confused answer.

Thanks,
-- 
William

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 198 bytes --]

Re: xen-netback fixes for stable 35876b5 3e55f8b

[Ian Campbell]

Adding Dave Miller, the networking maintainer. He needs to ack such
requests I think. Adding netdev too for good meassure.

On Fri, 2013-02-22 at 16:47 +0000, William Dauchy wrote:
> Hello,
> 
> I believe the two commits 35876b5 and 3e55f8b could be included in stable tree.
> 35876b5 is related to 4885628 already in the stable tree and fixes a
> possible oops.
> 3e55f8b is fixing another possible oops (see commit messages).

DaveM has these queued for stable already:
http://marc.info/?l=xen-devel&m=136086628711282&w=2

He likes to soak thing in mainline for a bit before forwarding to stable
which is likely why they aren't there yet
http://marc.info/?l=xen-devel&m=136029801624783&w=2

Ian.

Re: xen-netback fixes for stable 35876b5 3e55f8b

[William Dauchy]

[-- Attachment #1: Type: text/plain, Size: 255 bytes --]

On Feb22 17:44, Ian Campbell wrote:
> He likes to soak thing in mainline for a bit before forwarding to stable
> which is likely why they aren't there yet
> http://marc.info/?l=xen-devel&m=136029801624783&w=2

ack, didn't know that.

-- 
William

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 198 bytes --]

Re: xen-netback fixes for stable 35876b5 3e55f8b

[David Miller]

They are already queued up, see:

http://patchwork.ozlabs.org/bundle/davem/stable/?state=*