lkml.org 
[lkml]   [2014]   [Jan]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 3.11 013/208] xen-netback: fix refcnt unbalance for 3.11 and earlier versions
    Date
    3.11.10.3 -stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Wei Liu <wei.liu2@citrix.com>

    With the introduction of "xen-netback: Don't destroy the netdev until
    the vif is shut down" (upstream commit id 279f438e36), vif disconnect
    and free are separated. However in the backported verion reference
    counting code was not correctly modified, and the reset of vif->tx_irq
    was lost. If frontend goes through vif life cycle more than once the
    reference counting is skewed.

    This patch adds back the missing tx_irq reset line. It also moves
    several lines of the reference counting code to vif_free, so the moved
    code corresponds to the counterpart in vif_alloc, thus the reference
    counting is balanced.

    3.12 and onward versions are not affected by this bug, because reference
    counting code was removed due to the introduction of 1:1 model.

    This pacth should be backported to all stable verions which are lower
    than 3.12 and have 279f438e36.

    Reported-and-tested-by: Tomasz Wroblewski <tomasz.wroblewski@citrix.com>
    Signed-off-by: Wei Liu <wei.liu2@citrix.com>
    Cc: Ian Campbell <ian.campbell@citrix.com>
    Cc: Konrad Wilk <konrad.wilk@oracle.com>
    Cc: David Vrabel <david.vrabel@citrix.com>
    Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
    ---
    drivers/net/xen-netback/interface.c | 7 ++++---
    1 file changed, 4 insertions(+), 3 deletions(-)

    diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
    index d28324a..342d4e5 100644
    --- a/drivers/net/xen-netback/interface.c
    +++ b/drivers/net/xen-netback/interface.c
    @@ -418,9 +418,6 @@ void xenvif_disconnect(struct xenvif *vif)
    if (netif_carrier_ok(vif->dev))
    xenvif_carrier_off(vif);

    - atomic_dec(&vif->refcnt);
    - wait_event(vif->waiting_to_free, atomic_read(&vif->refcnt) == 0);
    -
    if (vif->tx_irq) {
    if (vif->tx_irq == vif->rx_irq)
    unbind_from_irqhandler(vif->tx_irq, vif);
    @@ -428,6 +425,7 @@ void xenvif_disconnect(struct xenvif *vif)
    unbind_from_irqhandler(vif->tx_irq, vif);
    unbind_from_irqhandler(vif->rx_irq, vif);
    }
    + vif->tx_irq = 0;
    }

    xen_netbk_unmap_frontend_rings(vif);
    @@ -435,6 +433,9 @@ void xenvif_disconnect(struct xenvif *vif)

    void xenvif_free(struct xenvif *vif)
    {
    + atomic_dec(&vif->refcnt);
    + wait_event(vif->waiting_to_free, atomic_read(&vif->refcnt) == 0);
    +
    unregister_netdev(vif->dev);

    free_netdev(vif->dev);
    --
    1.8.3.2


    \
     
     \ /
      Last update: 2014-01-13 20:41    [W:2.739 / U:0.428 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site