From d072218f214929194db06069564495b6b9fff34a Mon Sep 17 00:00:00 2001 From: Vitaly Kuznetsov Date: Mon, 15 Aug 2016 17:48:40 +0200 Subject: hv_netvsc: avoid deadlocks between rtnl lock and vf_use_cnt wait Here is a deadlock scenario: - netvsc_vf_up() schedules netvsc_notify_peers() work and quits. - netvsc_vf_down() runs before netvsc_notify_peers() gets executed. As it is being executed from netdev notifier chain we hold rtnl lock when we get here. - we enter while (atomic_read(&net_device_ctx->vf_use_cnt) != 0) loop and wait till netvsc_notify_peers() drops vf_use_cnt. - netvsc_notify_peers() starts on some other CPU but netdev_notify_peers() will hang on rtnl_lock(). - deadlock! Instead of introducing additional synchronization I suggest we drop gwrk.dwrk completely and call NETDEV_NOTIFY_PEERS directly. As we're acting under rtnl lock this is legitimate. Signed-off-by: Vitaly Kuznetsov Acked-by: Haiyang Zhang Signed-off-by: David S. Miller --- drivers/net/hyperv/hyperv_net.h | 7 ------- 1 file changed, 7 deletions(-) (limited to 'drivers/net/hyperv/hyperv_net.h') diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h index 3b3ecf237a12..591af71eae56 100644 --- a/drivers/net/hyperv/hyperv_net.h +++ b/drivers/net/hyperv/hyperv_net.h @@ -644,12 +644,6 @@ struct netvsc_reconfig { u32 event; }; -struct garp_wrk { - struct work_struct dwrk; - struct net_device *netdev; - struct net_device_context *net_device_ctx; -}; - /* The context of the netvsc device */ struct net_device_context { /* point back to our device context */ @@ -667,7 +661,6 @@ struct net_device_context { struct work_struct work; u32 msg_enable; /* debug level */ - struct garp_wrk gwrk; struct netvsc_stats __percpu *tx_stats; struct netvsc_stats __percpu *rx_stats; -- cgit v1.2.3