Message ID | CAJK669acbPLTxTDrk_uqdB2FmewcSA+HF0qEFADgT8YdfNMcpQ@mail.gmail.com |
---|---|
State | Changes Requested, archived |
Delegated to: | David Miller |
Headers | show |
On Tue, 2012-01-24 at 11:52 +0100, Sjur Brændeland wrote: > > Nack, we have to handle other device types than just ARPHDR_CAIF after > introducing > CAIF over USB/NCM. I'd rather fix this in netns by removing the BUG_ON > and return > NULL. How about this instead: [snip] I think that doing it this way is wrong for two reasons: 1. The code in net/ assumes net_generic is a trivial dereference and doesn't check that it's not NULL. This means that if anything goes wrong there you'll have a more dangerous NULL deref instead of a BUG(). 2. You'll need to add other device to that if() statement anyway, as it currently looks like this: cfg = get_cfcnfg(dev_net(dev)); caifdevs = caif_device_list(dev_net(dev)); if (!cfg || !caifdevs) return 0; caifd = caif_get(dev); if (caifd == NULL && dev->type != ARPHRD_CAIF) return 0; What my patch did was simply move the type check to above the net_generic call, it didn't add any new checks - which according to what you said, you'll need to do anyway.
diff --git a/include/net/netns/generic.h b/include/net/netns/generic.h index 3419bf5..0fc2eea 100644 --- a/include/net/netns/generic.h +++ b/include/net/netns/generic.h @@ -37,8 +37,10 @@ static inline void *net_generic(const struct net *net, int id rcu_read_lock(); ng = rcu_dereference(net->gen); - BUG_ON(id == 0 || id > ng->len); - ptr = ng->ptr[id - 1]; + if (id == 0 || id > ng->len) + ptr = NULL; + else + ptr = ng->ptr[id - 1]; rcu_read_unlock(); return ptr;