On Tue, 2016-09-06 at 10:36 -0700, Martin KaFai Lau wrote:
> On Fri, Sep 02, 2016 at 02:39:50PM -0400, Dave Jones wrote:
> > Neither the failure or success paths of ping_v6_sendmsg release
> > the dst it acquires. This leads to a flood of warnings from
> > "net/core/dst.c:288 dst_release" on older kernels that
> > don't have 8bf4ada2e21378816b28205427ee6b0e1ca4c5f1 backported.
> >
> > That patch optimistically hoped this had been fixed post 3.10, but
> > it seems at least one case wasn't, where I've seen this triggered
> > a lot from machines doing unprivileged icmp sockets.
> >
> > Cc: Martin Lau <ka...@fb.com>
> > Signed-off-by: Dave Jones <da...@codemonkey.org.uk>
> >
> > diff --git a/net/ipv6/ping.c b/net/ipv6/ping.c
> > index 0900352c924c..0e983b694ee8 100644
> > --- a/net/ipv6/ping.c
> > +++ b/net/ipv6/ping.c
> > @@ -126,8 +126,10 @@ static int ping_v6_sendmsg(struct sock *sk, struct
> > msghdr *msg, size_t len)
> > rt = (struct rt6_info *) dst;
> >
> > np = inet6_sk(sk);
> > - if (!np)
> > - return -EBADF;
> > + if (!np) {
> > + err = -EBADF;
> > + goto dst_err_out;
> > + }
> >
> > if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
> > fl6.flowi6_oif = np->mcast_oif;
> > @@ -163,6 +165,9 @@ static int ping_v6_sendmsg(struct sock *sk, struct
> > msghdr *msg, size_t len)
> > }
> > release_sock(sk);
> >
> > +dst_err_out:
> > + dst_release(dst);
> > +
> > if (err)
> > return err;
> >
>
> Acked-by: Martin KaFai Lau <ka...@fb.com>
This really does not make sense to me.
If np was NULL, we should have a crash before.
So we should remove this test, since it is absolutely useless.
