| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.0 004/139] net: avoid weird emergency message | Date | Thu, 23 May 2019 21:04:52 +0200 |
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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 @@ -8829,7 +8829,7 @@ 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;
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