From patchwork Wed May 24 12:09:44 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maurizio Lombardi X-Patchwork-Id: 9745899 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 1092F601C2 for ; Wed, 24 May 2017 12:12:06 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0094D28969 for ; Wed, 24 May 2017 12:12:06 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id E92212896F; Wed, 24 May 2017 12:12:05 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8804D28969 for ; Wed, 24 May 2017 12:12:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758593AbdEXMLM (ORCPT ); Wed, 24 May 2017 08:11:12 -0400 Received: from mx1.redhat.com ([209.132.183.28]:41020 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752119AbdEXMJq (ORCPT ); Wed, 24 May 2017 08:09:46 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 013C78004C; Wed, 24 May 2017 12:09:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 013C78004C Authentication-Results: ext-mx03.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx03.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=mlombard@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 013C78004C Received: from manaslu.brq.redhat.com (dhcp-27-224.brq.redhat.com [10.34.27.224]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2267B5C886; Wed, 24 May 2017 12:09:44 +0000 (UTC) From: Maurizio Lombardi To: QLogic-Storage-Upstream@qlogic.com Cc: linux-scsi@vger.kernel.org, jejb@linux.vnet.ibm.com, martin.petersen@oracle.com Subject: [PATCH] bnx2fc: fix race condition in bnx2fc_get_host_stats() Date: Wed, 24 May 2017 14:09:44 +0200 Message-Id: <1495627784-21048-1-git-send-email-mlombard@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Wed, 24 May 2017 12:09:46 +0000 (UTC) Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP If multiple tasks attempt to read the stats, it may happen that the start_req_done completion is re-initialized while still being used by another task, causing a list corruption. This patch fixes the bug by adding a mutex to serialize the calls to bnx2fc_get_host_stats(). WARNING: at lib/list_debug.c:48 list_del+0x6e/0xa0() (Not tainted) Hardware name: PowerEdge R820 list_del corruption. prev->next should be ffff882035627d90, but was ffff884069541588 Pid: 40267, comm: perl Not tainted 2.6.32-642.3.1.el6.x86_64 #1 Call Trace: [] ? warn_slowpath_common+0x91/0xe0 [] ? warn_slowpath_fmt+0x46/0x60 [] ? list_del+0x6e/0xa0 [] ? wait_for_common+0x14d/0x180 [] ? default_wake_function+0x0/0x20 [] ? wait_for_completion_timeout+0x13/0x20 [] ? bnx2fc_get_host_stats+0xa1/0x280 [bnx2fc] [] ? fc_stat_show+0x90/0xc0 [scsi_transport_fc] [] ? show_fcstat_tx_frames+0x16/0x20 [scsi_transport_fc] [] ? dev_attr_show+0x27/0x50 [] ? __get_free_pages+0xe/0x50 [] ? sysfs_read_file+0x111/0x200 [] ? vfs_read+0xb5/0x1a0 [] ? fget_light_pos+0x16/0x50 [] ? sys_read+0x51/0xb0 [] ? __audit_syscall_exit+0x25e/0x290 [] ? system_call_fastpath+0x16/0x1b Signed-off-by: Maurizio Lombardi Acked-by: Chad Dupuis --- drivers/scsi/bnx2fc/bnx2fc.h | 1 + drivers/scsi/bnx2fc/bnx2fc_fcoe.c | 10 ++++++++-- 2 files changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/scsi/bnx2fc/bnx2fc.h b/drivers/scsi/bnx2fc/bnx2fc.h index 4fc8ed5..1f424e4 100644 --- a/drivers/scsi/bnx2fc/bnx2fc.h +++ b/drivers/scsi/bnx2fc/bnx2fc.h @@ -191,6 +191,7 @@ struct bnx2fc_hba { struct bnx2fc_cmd_mgr *cmd_mgr; spinlock_t hba_lock; struct mutex hba_mutex; + struct mutex hba_stats_mutex; unsigned long adapter_state; #define ADAPTER_STATE_UP 0 #define ADAPTER_STATE_GOING_DOWN 1 diff --git a/drivers/scsi/bnx2fc/bnx2fc_fcoe.c b/drivers/scsi/bnx2fc/bnx2fc_fcoe.c index 93b5a00..902722d 100644 --- a/drivers/scsi/bnx2fc/bnx2fc_fcoe.c +++ b/drivers/scsi/bnx2fc/bnx2fc_fcoe.c @@ -663,15 +663,17 @@ static struct fc_host_statistics *bnx2fc_get_host_stats(struct Scsi_Host *shost) if (!fw_stats) return NULL; + mutex_lock(&hba->hba_stats_mutex); + bnx2fc_stats = fc_get_host_stats(shost); init_completion(&hba->stat_req_done); if (bnx2fc_send_stat_req(hba)) - return bnx2fc_stats; + goto unlock_stats_mutex; rc = wait_for_completion_timeout(&hba->stat_req_done, (2 * HZ)); if (!rc) { BNX2FC_HBA_DBG(lport, "FW stat req timed out\n"); - return bnx2fc_stats; + goto unlock_stats_mutex; } BNX2FC_STATS(hba, rx_stat2, fc_crc_cnt); bnx2fc_stats->invalid_crc_count += hba->bfw_stats.fc_crc_cnt; @@ -693,6 +695,9 @@ static struct fc_host_statistics *bnx2fc_get_host_stats(struct Scsi_Host *shost) memcpy(&hba->prev_stats, hba->stats_buffer, sizeof(struct fcoe_statistics_params)); + +unlock_stats_mutex: + mutex_unlock(&hba->hba_stats_mutex); return bnx2fc_stats; } @@ -1340,6 +1345,7 @@ static struct bnx2fc_hba *bnx2fc_hba_create(struct cnic_dev *cnic) } spin_lock_init(&hba->hba_lock); mutex_init(&hba->hba_mutex); + mutex_init(&hba->hba_stats_mutex); hba->cnic = cnic;