With new transparent VF support, it is possible to get a deadlock
when some of the deferred work is running and the unregister_vf
is trying to cancel the work element. The solution is to use
trylock and reschedule (similar to bonding and team device).
Reported-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
Fixes: 0c195567a8f6 ("netvsc: transparent VF management")
Signed-off-by: Stephen Hemminger <sthemmin@xxxxxxxxxxxxx>
---
drivers/net/hyperv/netvsc_drv.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index c71728d82049..e75c0f852a63 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -1601,7 +1601,11 @@ static void netvsc_vf_setup(struct work_struct *w)
struct net_device *ndev = hv_get_drvdata(ndev_ctx->device_ctx);
struct net_device *vf_netdev;
- rtnl_lock();
+ if (!rtnl_trylock()) {
+ schedule_work(w);
+ return;
+ }
+
vf_netdev = rtnl_dereference(ndev_ctx->vf_netdev);
if (vf_netdev)
__netvsc_vf_setup(ndev, vf_netdev);
@@ -1655,7 +1659,11 @@ static void netvsc_vf_update(struct work_struct *w)
struct net_device *vf_netdev;
bool vf_is_up;
- rtnl_lock();
+ if (!rtnl_trylock()) {
+ schedule_work(w);
+ return;
+ }
+
vf_netdev = rtnl_dereference(ndev_ctx->vf_netdev);
if (!vf_netdev)
goto unlock;
--
2.11.0
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