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=-13.8 required=3.0 tests=BAYES_00, 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 39F52C433ED for ; Fri, 2 Apr 2021 12:42:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E627F6115A for ; Fri, 2 Apr 2021 12:42:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229932AbhDBMmf (ORCPT ); Fri, 2 Apr 2021 08:42:35 -0400 Received: from mail-yb1-f177.google.com ([209.85.219.177]:46911 "EHLO mail-yb1-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229599AbhDBMmc (ORCPT ); Fri, 2 Apr 2021 08:42:32 -0400 Received: by mail-yb1-f177.google.com with SMTP id 8so4967750ybc.13 for ; Fri, 02 Apr 2021 05:42:31 -0700 (PDT) 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=5iDxqoL/eLy0OTQNjrpfUTPwzmCOZwOG7yvfuKlLZ3c=; b=EsDvPq5LiMBHtx8CX3IyZu5UwE5eB50rj5wIgazWfgOD48GeOt0L+uaqUeithXZ5P8 VfAOPZ7Vp47c5iAAu2oZB2fgiGR7RPILOs+fUi4Vr2GUc4I+rEmHYfUulZmlgBCInPTa ZrAaSRNMcW5B0uHeKVEjegAKecQgvHe3+XXWrSkN2nyY/YmQVsXKr2PTj1628kV4ZBgL DduWGZWaLUp4pG7YUvGR8UX0m0o8aVnCyzvJLQiGcy1DptfrFIyEbaUX80Dr1dxZ9Z4f 9pG3Z9n6PLJvSGt9uiuoNrYS7GXL//BsTgMaN0oLxEgkvS35txdXIczfNGuAlViPN++Y XRYg== X-Gm-Message-State: AOAM531sxRqs26ytVaK7SO2ie2sIyvDgDTg1n3SNVU6JqajdkMPyazDg zhpBD8KxwuJHkiatpcm7opK4jPWAw8VCvAxo28RyLjWcjRM= X-Google-Smtp-Source: ABdhPJzg0HF58ofbDl39CMZakkdShamGs3qYOXGKL2TlAZ5yQdYa3UYDniOEhtsa32zRcmf3s3RacIel9XI5UV5rVgc= X-Received: by 2002:a25:34d2:: with SMTP id b201mr5100299yba.307.1617367351248; Fri, 02 Apr 2021 05:42:31 -0700 (PDT) MIME-Version: 1.0 References: <20210402102245.1512583-1-mkl@pengutronix.de> In-Reply-To: <20210402102245.1512583-1-mkl@pengutronix.de> From: Vincent MAILHOL Date: Fri, 2 Apr 2021 21:42:20 +0900 Message-ID: Subject: Re: [PATCH] can: skb: alloc_can{,fd}_skb(): set "cf" to NULL if skb allocation fails To: Marc Kleine-Budde Cc: linux-can Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-can@vger.kernel.org On Fri. 2 Apr 2021 at 19:22, Marc Kleine-Budde wrote: > The handling of CAN bus errors typically consist of allocating a CAN > error SKB using alloc_can_err_skb() followed by stats handling and > filling the error details in the newly allocated CAN error SKB. Even > if the allocation of the SKB fails the stats handling should not be > skipped. > > The common pattern in CAN drivers is to allocate the skb and work on > the struct can_frame pointer "cf", if it has been assigned by > alloc_can_err_skb(). > > | skb = alloc_can_err_skb(priv->ndev, &cf); > | > | /* RX errors */ > | if (bdiag1 & (MCP251XFD_REG_BDIAG1_DCRCERR | > | MCP251XFD_REG_BDIAG1_NCRCERR)) { > | netdev_dbg(priv->ndev, "CRC error\n"); > | > | stats->rx_errors++; > | if (cf) > | cf->data[3] |= CAN_ERR_PROT_LOC_CRC_SEQ; > | } > > In case of an OOM alloc_can_err_skb() returns NULL, but doesn't set > "cf" to NULL as well. For the above pattern to work the "cf" has to be > initialized to NULL, which is easily forgotten. > > To solve this kind of problems, set "cf" to NULL if > alloc_can_err_skb() returns NULL. > > Suggested-by: Vincent MAILHOL > Signed-off-by: Marc Kleine-Budde > --- > drivers/net/can/dev/skb.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/can/dev/skb.c b/drivers/net/can/dev/skb.c > index 387c0bc0fb9c..61660248c69e 100644 > --- a/drivers/net/can/dev/skb.c > +++ b/drivers/net/can/dev/skb.c > @@ -183,8 +183,11 @@ struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf) > > skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) + > sizeof(struct can_frame)); > - if (unlikely(!skb)) > + if (unlikely(!skb)) { > + *cf = NULL; > + > return NULL; > + } > > skb->protocol = htons(ETH_P_CAN); > skb->pkt_type = PACKET_BROADCAST; > @@ -211,8 +214,11 @@ struct sk_buff *alloc_canfd_skb(struct net_device *dev, > > skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) + > sizeof(struct canfd_frame)); > - if (unlikely(!skb)) > + if (unlikely(!skb)) { > + *cfd = NULL; > + > return NULL; > + } > > skb->protocol = htons(ETH_P_CANFD); > skb->pkt_type = PACKET_BROADCAST; Thanks Marc! Reviewed-by: Vincent Mailhol