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[209.132.180.67]) by mx.google.com with ESMTP id l4si13595901pfg.76.2017.04.10.05.53.18; Mon, 10 Apr 2017 05:53:18 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753103AbdDJMwZ (ORCPT + 24 others); Mon, 10 Apr 2017 08:52:25 -0400 Received: from szxga03-in.huawei.com ([45.249.212.189]:5422 "EHLO dggrg03-dlp.huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752750AbdDJMwW (ORCPT ); Mon, 10 Apr 2017 08:52:22 -0400 Received: from 172.30.72.57 (EHLO DGGEML401-HUB.china.huawei.com) ([172.30.72.57]) by dggrg03-dlp.huawei.com (MOS 4.4.6-GA FastPath queued) with ESMTP id ALL62813; Mon, 10 Apr 2017 20:52:15 +0800 (CST) Received: from localhost.localdomain (10.67.212.75) by DGGEML401-HUB.china.huawei.com (10.3.17.32) with Microsoft SMTP Server id 14.3.301.0; Mon, 10 Apr 2017 20:52:05 +0800 From: John Garry To: , CC: , , , , , John Garry Subject: [PATCH 5/6] scsi: hisi_sas: fix NULL deference when TMF timeouts Date: Mon, 10 Apr 2017 21:22:00 +0800 Message-ID: <1491830521-21437-6-git-send-email-john.garry@huawei.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1491830521-21437-1-git-send-email-john.garry@huawei.com> References: <1491830521-21437-1-git-send-email-john.garry@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.67.212.75] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020206.58EB8001.005E, ss=1, re=0.000, recu=0.000, reip=0.000, cl=1, cld=1, fgs=0, ip=0.0.0.0, so=2014-11-16 11:51:01, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: 80b783d92e70782b24424872204e4a03 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If a TMF timeouts (maybe due to unlikely scenario of an expander being unplugged when TMF for remote device is active), when we eventually try to free the slot, we crash as we dereference the slot's task, which has already been released. As a fix, add checks in the slot release code for a NULL task. Signed-off-by: John Garry --- drivers/scsi/hisi_sas/hisi_sas_main.c | 60 +++++++++++++++++++---------------- 1 file changed, 33 insertions(+), 27 deletions(-) -- 1.9.1 diff --git a/drivers/scsi/hisi_sas/hisi_sas_main.c b/drivers/scsi/hisi_sas/hisi_sas_main.c index a5c6d06..7e6e882 100644 --- a/drivers/scsi/hisi_sas/hisi_sas_main.c +++ b/drivers/scsi/hisi_sas/hisi_sas_main.c @@ -77,17 +77,22 @@ static void hisi_sas_slot_index_init(struct hisi_hba *hisi_hba) void hisi_sas_slot_task_free(struct hisi_hba *hisi_hba, struct sas_task *task, struct hisi_sas_slot *slot) { - struct device *dev = &hisi_hba->pdev->dev; - struct domain_device *device = task->dev; - struct hisi_sas_device *sas_dev = device->lldd_dev; - if (!slot->task) - return; + if (task) { + struct device *dev = &hisi_hba->pdev->dev; + struct domain_device *device = task->dev; + struct hisi_sas_device *sas_dev = device->lldd_dev; - if (!sas_protocol_ata(task->task_proto)) - if (slot->n_elem) - dma_unmap_sg(dev, task->scatter, slot->n_elem, - task->data_dir); + if (!sas_protocol_ata(task->task_proto)) + if (slot->n_elem) + dma_unmap_sg(dev, task->scatter, slot->n_elem, + task->data_dir); + + task->lldd_task = NULL; + + if (sas_dev) + atomic64_dec(&sas_dev->running_req); + } if (slot->command_table) dma_pool_free(hisi_hba->command_table_pool, @@ -102,12 +107,10 @@ void hisi_sas_slot_task_free(struct hisi_hba *hisi_hba, struct sas_task *task, slot->sge_page_dma); list_del_init(&slot->entry); - task->lldd_task = NULL; slot->task = NULL; slot->port = NULL; hisi_sas_slot_index_free(hisi_hba, slot->idx); - if (sas_dev) - atomic64_dec(&sas_dev->running_req); + /* slot memory is fully zeroed when it is reused */ } EXPORT_SYMBOL_GPL(hisi_sas_slot_task_free); @@ -569,25 +572,23 @@ static void hisi_sas_port_notify_formed(struct asd_sas_phy *sas_phy) spin_unlock_irqrestore(&hisi_hba->lock, flags); } -static void hisi_sas_do_release_task(struct hisi_hba *hisi_hba, - struct sas_task *task, +static void hisi_sas_do_release_task(struct hisi_hba *hisi_hba, struct sas_task *task, struct hisi_sas_slot *slot) { - struct task_status_struct *ts; - unsigned long flags; - - if (!task) - return; + if (task) { + unsigned long flags; + struct task_status_struct *ts; - ts = &task->task_status; + ts = &task->task_status; - ts->resp = SAS_TASK_COMPLETE; - ts->stat = SAS_ABORTED_TASK; - spin_lock_irqsave(&task->task_state_lock, flags); - task->task_state_flags &= - ~(SAS_TASK_STATE_PENDING | SAS_TASK_AT_INITIATOR); - task->task_state_flags |= SAS_TASK_STATE_DONE; - spin_unlock_irqrestore(&task->task_state_lock, flags); + ts->resp = SAS_TASK_COMPLETE; + ts->stat = SAS_ABORTED_TASK; + spin_lock_irqsave(&task->task_state_lock, flags); + task->task_state_flags &= + ~(SAS_TASK_STATE_PENDING | SAS_TASK_AT_INITIATOR); + task->task_state_flags |= SAS_TASK_STATE_DONE; + spin_unlock_irqrestore(&task->task_state_lock, flags); + } hisi_sas_slot_task_free(hisi_hba, task, slot); } @@ -742,7 +743,12 @@ static int hisi_sas_exec_internal_tmf_task(struct domain_device *device, /* Even TMF timed out, return direct. */ if ((task->task_state_flags & SAS_TASK_STATE_ABORTED)) { if (!(task->task_state_flags & SAS_TASK_STATE_DONE)) { + struct hisi_sas_slot *slot = task->lldd_task; + dev_err(dev, "abort tmf: TMF task timeout\n"); + if (slot) + slot->task = NULL; + goto ex_err; } }