From 9b4e946ce14e20d7addbfb7d9139e604f9fda107 Mon Sep 17 00:00:00 2001 From: stephen hemminger Date: Thu, 24 Aug 2017 16:49:16 -0700 Subject: [PATCH] netvsc: fix deadlock betwen link status and removal There is a deadlock possible when canceling the link status delayed work queue. The removal process is run with RTNL held, and the link status callback is acquring RTNL. Resolve the issue by using trylock and rescheduling. If cancel is in process, that block it from happening. Fixes: 122a5f6410f4 ("staging: hv: use delayed_work for netvsc_send_garp()") Signed-off-by: Stephen Hemminger Signed-off-by: David S. Miller --- drivers/net/hyperv/netvsc_drv.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c index 0d78727f1a14..d91cbc6c3ca4 100644 --- a/drivers/net/hyperv/netvsc_drv.c +++ b/drivers/net/hyperv/netvsc_drv.c @@ -1269,7 +1269,12 @@ static void netvsc_link_change(struct work_struct *w) bool notify = false, reschedule = false; unsigned long flags, next_reconfig, delay; - rtnl_lock(); + /* if changes are happening, comeback later */ + if (!rtnl_trylock()) { + schedule_delayed_work(&ndev_ctx->dwork, LINKCHANGE_INT); + return; + } + net_device = rtnl_dereference(ndev_ctx->nvdev); if (!net_device) goto out_unlock; -- 2.20.1