From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Guilherme G. Piccoli" Subject: [PATCH net] igb: re-assign hw address pointer on reset after PCI error Date: Mon, 31 Oct 2016 18:12:29 -0200 Message-ID: <1477944749-22822-1-git-send-email-gpiccoli@linux.vnet.ibm.com> Cc: jeffrey.t.kirsher@intel.com, gpiccoli@linux.vnet.ibm.com, netdev@vger.kernel.org To: intel-wired-lan@lists.osuosl.org Return-path: Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:53036 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S946256AbcJaUMi (ORCPT ); Mon, 31 Oct 2016 16:12:38 -0400 Received: from pps.filterd (m0098393.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.17/8.16.0.17) with SMTP id u9VK8cnF037808 for ; Mon, 31 Oct 2016 16:12:38 -0400 Received: from e24smtp03.br.ibm.com (e24smtp03.br.ibm.com [32.104.18.24]) by mx0a-001b2d01.pphosted.com with ESMTP id 26e91agshd-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Mon, 31 Oct 2016 16:12:37 -0400 Received: from localhost by e24smtp03.br.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 31 Oct 2016 18:12:34 -0200 Received: from d24relay03.br.ibm.com (d24relay03.br.ibm.com [9.18.232.225]) by d24dlp01.br.ibm.com (Postfix) with ESMTP id 261C8352005F for ; Mon, 31 Oct 2016 16:12:05 -0400 (EDT) Received: from d24av04.br.ibm.com (d24av04.br.ibm.com [9.8.31.97]) by d24relay03.br.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u9VKCW0G34472096 for ; Mon, 31 Oct 2016 18:12:32 -0200 Received: from d24av04.br.ibm.com (localhost [127.0.0.1]) by d24av04.br.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id u9VKCVYZ026481 for ; Mon, 31 Oct 2016 18:12:32 -0200 Sender: netdev-owner@vger.kernel.org List-ID: Whenever the igb driver detects the result of a read operation returns a value composed only by F's (like 0xFFFFFFFF), it will detach the net_device, clear the hw_addr pointer and warn to the user that adapter's link is lost - those steps happen on igb_rd32(). In case a PCI error happens on Power architecture, there's a recovery mechanism called EEH, that will reset the PCI slot and call driver's handlers to reset the adapter and network functionality as well. We observed that once hw_addr is NULL after the error is detected on igb_rd32(), it's never assigned back, so in the process of resetting the network functionality we got a NULL pointer dereference in both igb_configure_tx_ring() and igb_configure_rx_ring(). In order to avoid such bug, we re-assign the hw_addr value in the beginning of the function igb_reset(), in case the hw_addr is NULL when we reach that path. Reported-by: Anthony H. Thai Reported-by: Harsha Thyagaraja Signed-off-by: Guilherme G. Piccoli --- drivers/net/ethernet/intel/igb/igb_main.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c index edc9a6a..c19119c 100644 --- a/drivers/net/ethernet/intel/igb/igb_main.c +++ b/drivers/net/ethernet/intel/igb/igb_main.c @@ -1873,6 +1873,13 @@ void igb_reset(struct igb_adapter *adapter) struct e1000_fc_info *fc = &hw->fc; u32 pba, hwm; + /* In case of PCI error, adapter might have lost its HW + * address; if we reached this point after an error scenario, + * we should re-assign the hw_addr based on the saved io_addr. + */ + if (!hw->hw_addr) + hw->hw_addr = adapter->io_addr; + /* Repartition Pba for greater than 9k mtu * To take effect CTRL.RST is required. */ -- 2.1.0