Re: [Xen-devel] [PATCH linux-2.6.18-xen] fix xenbus_transaction_start() hang caused by double xenbus_transaction_end()

["Jan Beulich" <JBeulich@xxxxxxxxxx>]

>>> On 12.05.11 at 12:24, Laszlo Ersek <lersek@xxxxxxxxxx> wrote:
> fix xenbus_transaction_start() hang caused by double xenbus_transaction_end()
> 
> vbd_resize() up_read()'s xs_state.suspend_mutex twice in a row via double
> xenbus_transaction_end() calls. The next down_read() in
> xenbus_transaction_start() (at eg. the next resize attempt) hangs.
> 
> See RHBZ#618317.
> 
> Thanks for considering.
> 
> Signed-off-by: Laszlo Ersek <lersek@xxxxxxxxxx>

Acked-by: Jan Beulich <jbeulich@xxxxxxxxxx>

(I wonder how this ever passed any testing.)

The same would be needed for pv-ops too afaics.

Jan

> ---
>  drivers/xen/blkback/vbd.c |    1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/xen/blkback/vbd.c b/drivers/xen/blkback/vbd.c
> --- a/drivers/xen/blkback/vbd.c
> +++ b/drivers/xen/blkback/vbd.c
> @@ -156,6 +156,7 @@
>               goto again;
>       if (err)
>               printk(KERN_WARNING "Error ending transaction");
> +     return;
>  abort:
>       xenbus_transaction_end(xbt, 1);
>  }
> 
> 
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> http://lists.xensource.com/xen-devel 




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