From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 86CAAC433DB for ; Mon, 15 Feb 2021 03:47:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 50B686023B for ; Mon, 15 Feb 2021 03:47:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229870AbhBODrq (ORCPT ); Sun, 14 Feb 2021 22:47:46 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57962 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229865AbhBODrp (ORCPT ); Sun, 14 Feb 2021 22:47:45 -0500 Received: from mail-oi1-x235.google.com (mail-oi1-x235.google.com [IPv6:2607:f8b0:4864:20::235]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4FEDDC061756 for ; Sun, 14 Feb 2021 19:47:05 -0800 (PST) Received: by mail-oi1-x235.google.com with SMTP id i3so6503172oif.1 for ; Sun, 14 Feb 2021 19:47:05 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=DyqWbTqa6RPmmicUNXCsXIT8lyN+mZX4oU1sw6bj9LU=; b=Vad/da0KIYz952KCnjE0VCNL/lCMh47/QPw8RnF9HWJ/2XvUc7q8tJQN10AAxhoKa3 yOffwGkj3KKNCX9Mu7fNBjB1WusIvflnZo+VFaE3wYiw6jlzeoOqzvh4+TiTNVtKwyjo hPgIGFuumhzHIXOzAHef6dxFVbDB9SmdXNGe5vBmHSIkAmGwA9hYOlGXMo6Xu+vtmSqp XhH2CwzyRedVPQ4NS2m8a9sa1RxsiGYVARBmASDal28rBWRE5KQ7wLSmH6/QHK8j8Rc3 OcX9tOiltgbSOvrwTvp1xhfjM7PC+3I0GQHkjGGtqLmpSGUJdf19mpUM4pyYNEMMIZkY TgSA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=DyqWbTqa6RPmmicUNXCsXIT8lyN+mZX4oU1sw6bj9LU=; b=rmr65/yMFESG5R0fY8lcGfTqEM0j6FjgEdTsFC+gguJrSMqHEypRbuzxPiO++tA3zK LJE+MZoC6JtkBhGIGwaxwXtrA0rBBHxXs2+BFb0pE0K8RiyU2IrE34Ysh1lfUeQWIMSz JkW3KlokMhEsb3S1imjRENLVoWdupexPnY4uG+iC7dHFDDPTYQHvl2PJqyixzMJvkj09 84hso2REQkoey4O6YF5TU+a/0x0/1v90VwYicaLTij6UqQVtekffcHcXIVQGGe2M4csY h37lT2GltiZcrq9TRrUrphSFggI9I6MJP1jCswpjmZDjp/HPnE2l/0reBZ7nK/RfweSM l9rA== X-Gm-Message-State: AOAM532e9OyRifaBsL+cJSxFrALq5jbjJD9TD3DLWVbfy+Vs7TNg3nou X5Iv49UByoZ5mfSDq7krb7IKfiVGcuGojMTkNIo= X-Google-Smtp-Source: ABdhPJxWzm2A0xaZxf6QTL+JNK36fGoPQuma0CSI4CJGyxuZS8aHlGctenXLnPIUyqxI1azIkZfNzcxpZ+oIezxPbPc= X-Received: by 2002:aca:3906:: with SMTP id g6mr7171176oia.169.1613360824730; Sun, 14 Feb 2021 19:47:04 -0800 (PST) MIME-Version: 1.0 References: <20210214222630.3901-1-rpearson@hpe.com> In-Reply-To: <20210214222630.3901-1-rpearson@hpe.com> From: Zhu Yanjun Date: Mon, 15 Feb 2021 11:46:54 +0800 Message-ID: Subject: Re: [PATCH for-next] RDMA/rxe: Fix ib_device reference counting (again) To: Bob Pearson Cc: Jason Gunthorpe , RDMA mailing list , Bob Pearson Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On Mon, Feb 15, 2021 at 6:27 AM Bob Pearson wrote: > > Three errors occurred in the fix referenced below. > > 1) The on and off again 'if (skb)' got dropped but was really > needed in rxe_rcv_mcast_pkt() to prevent calling ib_device_put() > on the non-error path. > > 2) Extending the reference taken by rxe_get_dev_from_net() in > rxe_udp_encap_recv() until each skb is freed was not matched by > a reference in the loopback path resulting in underflows. > > 3) In rxe_comp.c the function free_pkt() did not clear skb which > triggered a warning at done: and could possibly at exit: in > rxe_completer(). The WARN_ONCE() calls are not required at done: > and only in one place before going to exit. > > This patch fixes these errors. > > Fixes: 899aba891cab ("RDMA/rxe: Fix FIXME in rxe_udp_encap_recv()") > Signed-off-by: Bob Pearson > --- > drivers/infiniband/sw/rxe/rxe_comp.c | 5 +++-- > drivers/infiniband/sw/rxe/rxe_net.c | 7 ++++++- > drivers/infiniband/sw/rxe/rxe_recv.c | 6 ++++-- > 3 files changed, 13 insertions(+), 5 deletions(-) > > diff --git a/drivers/infiniband/sw/rxe/rxe_comp.c b/drivers/infiniband/sw/rxe/rxe_comp.c > index a8ac791a1bb9..13fc5a1cced1 100644 > --- a/drivers/infiniband/sw/rxe/rxe_comp.c > +++ b/drivers/infiniband/sw/rxe/rxe_comp.c > @@ -671,6 +671,9 @@ int rxe_completer(void *arg) > * it down the road or let it expire > */ > > + /* warn if we did receive a packet */ > + WARN_ON_ONCE(skb); > + > /* there is nothing to retry in this case */ > if (!wqe || (wqe->state == wqe_state_posted)) > goto exit; > @@ -750,7 +753,6 @@ int rxe_completer(void *arg) > /* we come here if we are done with processing and want the task to > * exit from the loop calling us > */ > - WARN_ON_ONCE(skb); > rxe_drop_ref(qp); > return -EAGAIN; > > @@ -758,7 +760,6 @@ int rxe_completer(void *arg) > /* we come here if we have processed a packet we want the task to call > * us again to see if there is anything else to do > */ > - WARN_ON_ONCE(skb); > rxe_drop_ref(qp); > return 0; > } > diff --git a/drivers/infiniband/sw/rxe/rxe_net.c b/drivers/infiniband/sw/rxe/rxe_net.c > index 36d56163afac..8e81df578552 100644 > --- a/drivers/infiniband/sw/rxe/rxe_net.c > +++ b/drivers/infiniband/sw/rxe/rxe_net.c > @@ -406,12 +406,17 @@ int rxe_send(struct rxe_pkt_info *pkt, struct sk_buff *skb) > > void rxe_loopback(struct sk_buff *skb) > { > + struct rxe_pkt_info *pkt = SKB_TO_PKT(skb); > + > if (skb->protocol == htons(ETH_P_IP)) > skb_pull(skb, sizeof(struct iphdr)); > else > skb_pull(skb, sizeof(struct ipv6hdr)); > > - rxe_rcv(skb); > + if (WARN_ON(!ib_device_try_get(&pkt->rxe->ib_dev))) > + kfree_skb(skb); > + else > + rxe_rcv(skb); > } > > struct sk_buff *rxe_init_packet(struct rxe_dev *rxe, struct rxe_av *av, > diff --git a/drivers/infiniband/sw/rxe/rxe_recv.c b/drivers/infiniband/sw/rxe/rxe_recv.c > index 8a48a33d587b..a5e330e3bbce 100644 > --- a/drivers/infiniband/sw/rxe/rxe_recv.c > +++ b/drivers/infiniband/sw/rxe/rxe_recv.c > @@ -299,8 +299,10 @@ static void rxe_rcv_mcast_pkt(struct rxe_dev *rxe, struct sk_buff *skb) > > err1: > /* free skb if not consumed */ > - kfree_skb(skb); > - ib_device_put(&rxe->ib_dev); > + if (unlikely(skb)) { >From Leon Romanovsky " Please don't put "if (a) kfree(a);" constructions unless you want to deal with daily flux of patches with attempt to remove "if". " Zhu Yanjun > + kfree_skb(skb); > + ib_device_put(&rxe->ib_dev); > + } > } > > /** > -- > 2.27.0 >