From patchwork Mon Feb 4 19:49:42 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Gortmaker X-Patchwork-Id: 218050 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 817A72C02BC for ; Tue, 5 Feb 2013 06:50:13 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755089Ab3BDTuD (ORCPT ); Mon, 4 Feb 2013 14:50:03 -0500 Received: from mail.windriver.com ([147.11.1.11]:35475 "EHLO mail.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755063Ab3BDTuB (ORCPT ); Mon, 4 Feb 2013 14:50:01 -0500 Received: from yow-lpgnfs-02.corp.ad.wrs.com (yow-lpgnfs-02.wrs.com [128.224.149.8]) by mail.windriver.com (8.14.5/8.14.3) with ESMTP id r14Jnv53020640; Mon, 4 Feb 2013 11:49:57 -0800 (PST) From: Paul Gortmaker To: David Miller Cc: netdev@vger.kernel.org, Paul Gortmaker , Claudiu Manoil Subject: [PATCH net-next] gianfar: dont conditionally alloc Rx/Err irq structs Date: Mon, 4 Feb 2013 14:49:42 -0500 Message-Id: <1360007382-7876-1-git-send-email-paul.gortmaker@windriver.com> X-Mailer: git-send-email 1.8.1.2 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Commit ee873fda3bec7c668407b837fc5519eb961fcd37 "gianfar: Pack struct gfar_priv_grp into three cachelines" causes the following null dereference at driver init on sbc8548: libphy: Freescale PowerQUICC MII Bus: probed Unable to handle kernel paging request for data at address 0x00000000 Faulting instruction address: 0xc01d6a38 Oops: Kernel access of bad area, sig: 11 [#1] [...] NIP [c01d6a38] gfar_parse_group+0x228/0x280 LR [c01d6a34] gfar_parse_group+0x224/0x280 Call Trace: [ef82dd60] [c01d6a34] gfar_parse_group+0x224/0x280 (unreliable) [ef82dd90] [c01d73a4] gfar_probe+0x284/0xfe0 The reason is that the commit also changed the allocation of the Rx and error handling irq structs to be skipped for !MQ_MG_MODE. In the !MQ_MG_MODE case, only the Tx irq struct is allocated. Digging further, we see that MQ_MG_MODE is set only if we find the OF compatible string "fsl,etsec2". A quick grep in the dts directory shows lots of boards that support Rx/Tx/Err, but without this specific compat string. And hence they go after the unallocated Rx/Error structs and cause the above oops. Hence such a change can not be deployed until all the dts files are updated and sufficiently deployed. Further, the optimization is of limited value, since the kmalloc'd struct in question has only a single unsigned int, and an (IFNAMSIZ + 6) sized string. Note that no changes to the freeing code are needed here, as it already did an unconditional free of Rx/Tx/Error gfar_irqinfo. Cc: Claudiu Manoil Signed-off-by: Paul Gortmaker --- drivers/net/ethernet/freescale/gianfar.c | 16 ++++------------ 1 file changed, 4 insertions(+), 12 deletions(-) diff --git a/drivers/net/ethernet/freescale/gianfar.c b/drivers/net/ethernet/freescale/gianfar.c index 19c54a0..75734bf 100644 --- a/drivers/net/ethernet/freescale/gianfar.c +++ b/drivers/net/ethernet/freescale/gianfar.c @@ -580,19 +580,11 @@ static int gfar_parse_group(struct device_node *np, u32 *queue_mask; int i; - if (priv->mode == MQ_MG_MODE) { - for (i = 0; i < GFAR_NUM_IRQS; i++) { - grp->irqinfo[i] = kzalloc(sizeof(struct gfar_irqinfo), - GFP_KERNEL); - if (!grp->irqinfo[i]) - return -ENOMEM; - } - } else { - grp->irqinfo[GFAR_TX] = kzalloc(sizeof(struct gfar_irqinfo), - GFP_KERNEL); - if (!grp->irqinfo[GFAR_TX]) + for (i = 0; i < GFAR_NUM_IRQS; i++) { + grp->irqinfo[i] = kzalloc(sizeof(struct gfar_irqinfo), + GFP_KERNEL); + if (!grp->irqinfo[i]) return -ENOMEM; - grp->irqinfo[GFAR_RX] = grp->irqinfo[GFAR_ER] = NULL; } grp->regs = of_iomap(np, 0);