On Mon, 2025-03-17 at 21:37 +0000, Trond Myklebust wrote: > On Mon, 2025-03-17 at 17:36 -0400, Jeff Layton wrote: > > On Mon, 2025-03-17 at 21:28 +0000, Trond Myklebust wrote: > > > On Mon, 2025-03-17 at 17:00 -0400, Jeff Layton wrote: > > > > With the move to having sunrpc client xprts not hold active > > > > references > > > > to the net namespace, there is no need to upgrade the socket's > > > > reference > > > > in xs_create_sock. Just keep the passive reference instead. > > > > > > > > Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx> > > > > --- > > > > net/sunrpc/xprtsock.c | 3 --- > > > > 1 file changed, 3 deletions(-) > > > > > > > > diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c > > > > index > > > > 83cc095846d356f24aed26e2f98525662a6cff1f..0c3d7552f772d6f8477a3ae > > > > d8f0 > > > > c513b62cdf589 100644 > > > > --- a/net/sunrpc/xprtsock.c > > > > +++ b/net/sunrpc/xprtsock.c > > > > @@ -1941,9 +1941,6 @@ static struct socket *xs_create_sock(struct > > > > rpc_xprt *xprt, > > > > goto out; > > > > } > > > > > > > > - if (protocol == IPPROTO_TCP) > > > > - sk_net_refcnt_upgrade(sock->sk); > > > > - > > > > filp = sock_alloc_file(sock, O_NONBLOCK, NULL); > > > > if (IS_ERR(filp)) > > > > return ERR_CAST(filp); > > > > > > > > > > Is this not going to reintroduce the bug described by > > > https://lore.kernel.org/netdev/67b72aeb.050a0220.14d86d.0283.GAE@xxxxxxxxxx/T/#u > > > ? > > > > > > As I understand it, the problem has nothing to do with whether or > > > not > > > NFS or the RPC layer holds a reference to the net namespace, but > > > rather > > > whether there are still packets in the socket queues at the time > > > when > > > that net namespace is being freed. > > > > > > > > > > I don't think so. That syzkaller report was closed by this patch: > > > > 5c70eb5c593d net: better track kernel sockets lifetime > > > > That says: > > > > "To fix this, make sure that kernel sockets own a reference on > > net > > passive." > > > > With this, we still do keep a passive reference on the net in the > > socket, which I think is enough. > > No. You just removed that by reverting the patch that assigns the > passive reference. > That's not how I read sk_net_refcnt_upgrade(). The socket already holds a passive reference on the netns. sk_net_refcnt_upgrade() puts that reference and then gets an active reference to the netns. With this patchset, we just need to keep the passive one (I think). -- Jeff Layton <jlayton@xxxxxxxxxx>
