On Tue, Mar 5, 2019 at 7:11 AM Eric Dumazet <eduma...@google.com> wrote: >
> > > > My original suggestion was to use VM_WARN_ONCE() so that the debug checks > > would > > be compiled out by the compiler, unless you compile a debug kernel. > > > > Something like : > > > > diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c > > index > > ad07dd71063da09843ccfbd3e00d3f41567e1205..889563a66dde2a41c198d92a80183cf5382f632d > > 100644 > > --- a/net/ipv4/tcp.c > > +++ b/net/ipv4/tcp.c > > @@ -943,6 +943,9 @@ ssize_t do_tcp_sendpages(struct sock *sk, struct page > > *page, int offset, > > ssize_t copied; > > long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT); > > > > + if (VM_WARN_ONCE(PageSlab(page)), "page must not be a Slab one") > > + return -EINVAL; > > + Well, VM_WARN_ONCE() returns 1 if !CONFIG_DEBUG_VM, so it is not behaving like WARN_ONCE(), which is unfortunate. But you get the idea ;) > > /* Wait for a connection to finish. One exception is TCP Fast Open > > * (passive side) where data is allowed to be sent before a > > connection > > * is fully established. > > > > > > For some reason you added a fallback :/ > >
