From: Eric Dumazet edumazet@google.com
[ 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 edumazet@google.com Reported-by: syzbot syzkaller@googlegroups.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/core/dev.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/net/core/dev.c +++ b/net/core/dev.c @@ -6986,7 +6986,7 @@ static void netdev_wait_allrefs(struct n
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;