From 3b4c15ed45f91b0c823a2597dfd0474baed2b76f Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 27 May 2019 20:20:57 +0800 Subject: [PATCH] net: avoid weird emergency message [ Upstream commit d7c04b05c9ca14c55309eb139430283a45c4c25f ] When host is under high stress, it is very possible thread running netdev_wait_allrefs() returns from msleep(250) 10 seconds late. This leads to these messages in the syslog : [...] unregister_netdevice: waiting for syz_tun to become free. Usage count = 0 If the device refcount is zero, the wait is over. Signed-off-by: Eric Dumazet Reported-by: syzbot Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman Signed-off-by: Yang Yingliang --- net/core/dev.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/core/dev.c b/net/core/dev.c index 3bcec116a5f2..13a82744a00a 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -8716,7 +8716,7 @@ static void netdev_wait_allrefs(struct net_device *dev) refcnt = netdev_refcnt_read(dev); - if (time_after(jiffies, warning_time + 10 * HZ)) { + if (refcnt && time_after(jiffies, warning_time + 10 * HZ)) { pr_emerg("unregister_netdevice: waiting for %s to become free. Usage count = %d\n", dev->name, refcnt); warning_time = jiffies; -- GitLab