Re: [GIT]: Networking

Linus Torvalds
2008-07-21T16:50:11Z

On Sun, 20 Jul 2008, David Miller wrote:
>
> Alexey, please try this patch:
>
> atl1: Do not wake queue before queue has been started.

David, can we please make this all a bit less fragile?

There are _millions_ of network drivers, and these changes seem to have
broken not just common drivers, but also drivers that "work" seem to now
have broken suspend/resume.

There's at least one report of suspend apparently oopsing now, and I
assume it's basically the same thing - it was bisected down to that same
37437bb2e1ae8af470dfcd5b4ff454110894ccaf commit ("pkt_sched: Schedule
qdiscs instead of netdev_queue.")

Why is it so unnecessarily fragile to begin with? Especially for stuff
that happens at bootup or suspend, doing a BUG_ON() is _particularly_
painful, because a dead machine means that you cannot get any logs or
anything else.

So wouldn't it be *much* better to do something like the appended, and at
least try to limp on, and maybe have a system that people can get logs
out of?

Linus

---
net/core/dev.c | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 2eed17b..43ab4f5 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1325,7 +1325,8 @@ static void dev_queue_xmit_nit(struct sk_buff *skb, struct net_device *dev)

void __netif_schedule(struct Qdisc *q)
{
- BUG_ON(q == &noop_qdisc);
+ if (WARN_ON_ONCE(q == &noop_qdisc))
+ return;

if (!test_and_set_bit(__QDISC_STATE_SCHED, &q->state)) {
struct softnet_data *sd;
---