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Message-ID: <a3e713f2663bffbb71400563ba6d3735@codeaurora.org>
Date:   Thu, 13 Feb 2020 14:37:57 +0530
From:   gubbaven@...eaurora.org
To:     Abhishek Pandit-Subedi <abhishekpandit@...omium.org>
Cc:     Marcel Holtmann <marcel@...tmann.org>,
        Johan Hedberg <johan.hedberg@...il.com>,
        Matthias Kaehlcke <mka@...omium.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Bluez mailing list <linux-bluetooth@...r.kernel.org>,
        robh@...nel.org, hemantg@...eaurora.org,
        linux-arm-msm@...r.kernel.org, bgodavar@...eaurora.org,
        Claire Chang <tientzu@...omium.org>,
        Sean Paul <seanpaul@...omium.org>, rjliao@...eaurora.org,
        Yoni Shavit <yshavit@...gle.com>
Subject: Re: [PATCH v2] Bluetooth: hci_qca: Bug fixes while collecting
 controller memory dump

Hi Abhishek,

Sure I will update and post next patch set.

Regards,
Lakshmi Narayana.
On 2020-02-12 22:27, Abhishek Pandit-Subedi wrote:
> Hi Venkata,
> 
> I would suggest removing the memdump_timer entirely and making the
> ctrl_memdump_timeout into struct delayed_work.
> 
> Instead of using mod_timer to get the callback ready, you would
> instead call `queue_delayed_work(qca->workqueue,
> &qca->ctrl_memdump_timeout, MEMDUMP_TIMEOUT_MS);` and instead of
> del_timer, you would instead
> `cancel_delayed_work(&qca->ctrl_memdump_timeout)` if mutex is held or
> `cancel_delayed_work_sync(&qca->ctrl_memdump_timeout)` if mutex is not
> held.
> 
> Other than that, everything else looks good to me.
> 
> On Wed, Feb 12, 2020 at 7:51 AM Venkata Lakshmi Narayana Gubba
> <gubbaven@...eaurora.org> wrote:
>> 
>> This patch will fix the below issues
>>    1.Fixed race conditions while accessing memory dump state flags.
>>    2.Updated with actual context of timer in hci_memdump_timeout()
>>    3.Updated injecting hardware error event if the dumps failed to 
>> receive.
>>    4.Once timeout is triggered, stopping the memory dump collections.
>> 
>> Possible scenarios while collecting memory dump:
>> 
>> Scenario 1:
>> 
>> Memdump event from firmware
>> Some number of memdump events with seq #
>> Hw error event
>> Reset
>> 
>> Scenario 2:
>> 
>> Memdump event from firmware
>> Some number of memdump events with seq #
>> Timeout schedules hw_error_event if hw error event is not received 
>> already
>> hw_error_event clears the memdump activity
>> reset
>> 
>> Scenario 3:
>> 
>> hw_error_event sends memdump command to firmware and waits for 
>> completion
>> Some number of memdump events with seq #
>> hw error event
>> reset
>> 
>> Fixes: d841502c79e3 ("Bluetooth: hci_qca: Collect controller memory 
>> dump during SSR")
>> Reported-by: Abhishek Pandit-Subedi <abhishekpandit@...omium.org>
>> Signed-off-by: Venkata Lakshmi Narayana Gubba 
>> <gubbaven@...eaurora.org>
>> ---
>>  drivers/bluetooth/hci_qca.c | 96 
>> ++++++++++++++++++++++++++++++++-------------
>>  1 file changed, 69 insertions(+), 27 deletions(-)
>> 
>> diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
>> index eacc65b..80ee838 100644
>> --- a/drivers/bluetooth/hci_qca.c
>> +++ b/drivers/bluetooth/hci_qca.c
>> @@ -29,6 +29,7 @@
>>  #include <linux/platform_device.h>
>>  #include <linux/regulator/consumer.h>
>>  #include <linux/serdev.h>
>> +#include <linux/mutex.h>
>>  #include <asm/unaligned.h>
>> 
>>  #include <net/bluetooth/bluetooth.h>
>> @@ -69,7 +70,8 @@ enum qca_flags {
>>         QCA_IBS_ENABLED,
>>         QCA_DROP_VENDOR_EVENT,
>>         QCA_SUSPENDING,
>> -       QCA_MEMDUMP_COLLECTION
>> +       QCA_MEMDUMP_COLLECTION,
>> +       QCA_HW_ERROR_EVENT
>>  };
>> 
>> 
>> @@ -145,11 +147,13 @@ struct qca_data {
>>         struct work_struct ws_rx_vote_off;
>>         struct work_struct ws_tx_vote_off;
>>         struct work_struct ctrl_memdump_evt;
>> +       struct work_struct ctrl_memdump_timeout;
>>         struct qca_memdump_data *qca_memdump;
>>         unsigned long flags;
>>         struct completion drop_ev_comp;
>>         wait_queue_head_t suspend_wait_q;
>>         enum qca_memdump_states memdump_state;
>> +       struct mutex hci_memdump_lock;
>> 
>>         /* For debugging purpose */
>>         u64 ibs_sent_wacks;
>> @@ -524,21 +528,33 @@ static void hci_ibs_wake_retrans_timeout(struct 
>> timer_list *t)
>> 
>>  static void hci_memdump_timeout(struct timer_list *t)
>>  {
>> -       struct qca_data *qca = from_timer(qca, t, tx_idle_timer);
>> -       struct hci_uart *hu = qca->hu;
>> -       struct qca_memdump_data *qca_memdump = qca->qca_memdump;
>> -       char *memdump_buf = qca_memdump->memdump_buf_tail;
>> -
>> -       bt_dev_err(hu->hdev, "clearing allocated memory due to memdump 
>> timeout");
>> -       /* Inject hw error event to reset the device and driver. */
>> -       hci_reset_dev(hu->hdev);
>> -       vfree(memdump_buf);
>> -       kfree(qca_memdump);
>> -       qca->memdump_state = QCA_MEMDUMP_TIMEOUT;
>> +       struct qca_data *qca = from_timer(qca, t, memdump_timer);
>> +
>> +       queue_work(qca->workqueue, &qca->ctrl_memdump_timeout);
>>         del_timer(&qca->memdump_timer);
>> -       cancel_work_sync(&qca->ctrl_memdump_evt);
>>  }
>> 
>> +static void qca_controller_memdump_timeout(struct work_struct *work)
>> +{
>> +       struct qca_data *qca = container_of(work, struct qca_data,
>> +                                       ctrl_memdump_timeout);
>> +       struct hci_uart *hu = qca->hu;
>> +
>> +       mutex_lock(&qca->hci_memdump_lock);
>> +       if (test_bit(QCA_MEMDUMP_COLLECTION, &qca->flags)) {
>> +               qca->memdump_state = QCA_MEMDUMP_TIMEOUT;
>> +               if (!test_bit(QCA_HW_ERROR_EVENT, &qca->flags)) {
>> +                       /* Inject hw error event to reset the device
>> +                        * and driver.
>> +                        */
>> +                       hci_reset_dev(hu->hdev);
>> +               }
>> +       }
>> +
>> +       mutex_unlock(&qca->hci_memdump_lock);
>> +}
>> +
>> +
>>  /* Initialize protocol */
>>  static int qca_open(struct hci_uart *hu)
>>  {
>> @@ -558,6 +574,7 @@ static int qca_open(struct hci_uart *hu)
>>         skb_queue_head_init(&qca->tx_wait_q);
>>         skb_queue_head_init(&qca->rx_memdump_q);
>>         spin_lock_init(&qca->hci_ibs_lock);
>> +       mutex_init(&qca->hci_memdump_lock);
>>         qca->workqueue = alloc_ordered_workqueue("qca_wq", 0);
>>         if (!qca->workqueue) {
>>                 BT_ERR("QCA Workqueue not initialized properly");
>> @@ -570,6 +587,7 @@ static int qca_open(struct hci_uart *hu)
>>         INIT_WORK(&qca->ws_rx_vote_off, 
>> qca_wq_serial_rx_clock_vote_off);
>>         INIT_WORK(&qca->ws_tx_vote_off, 
>> qca_wq_serial_tx_clock_vote_off);
>>         INIT_WORK(&qca->ctrl_memdump_evt, qca_controller_memdump);
>> +       INIT_WORK(&qca->ctrl_memdump_timeout, 
>> qca_controller_memdump_timeout);
>>         init_waitqueue_head(&qca->suspend_wait_q);
>> 
>>         qca->hu = hu;
>> @@ -963,11 +981,20 @@ static void qca_controller_memdump(struct 
>> work_struct *work)
>> 
>>         while ((skb = skb_dequeue(&qca->rx_memdump_q))) {
>> 
>> +               mutex_lock(&qca->hci_memdump_lock);
>> +               /* Skip processing the received packets if timeout 
>> detected. */
>> +               if (qca->memdump_state == QCA_MEMDUMP_TIMEOUT) {
>> +                       mutex_unlock(&qca->hci_memdump_lock);
>> +                       return;
>> +               }
>> +
>>                 if (!qca_memdump) {
>>                         qca_memdump = kzalloc(sizeof(struct 
>> qca_memdump_data),
>>                                               GFP_ATOMIC);
>> -                       if (!qca_memdump)
>> +                       if (!qca_memdump) {
>> +                               mutex_unlock(&qca->hci_memdump_lock);
>>                                 return;
>> +                       }
>> 
>>                         qca->qca_memdump = qca_memdump;
>>                 }
>> @@ -992,6 +1019,7 @@ static void qca_controller_memdump(struct 
>> work_struct *work)
>>                         if (!(dump_size)) {
>>                                 bt_dev_err(hu->hdev, "Rx invalid 
>> memdump size");
>>                                 kfree_skb(skb);
>> +                               mutex_unlock(&qca->hci_memdump_lock);
>>                                 return;
>>                         }
>> 
>> @@ -1016,6 +1044,7 @@ static void qca_controller_memdump(struct 
>> work_struct *work)
>>                         kfree(qca_memdump);
>>                         kfree_skb(skb);
>>                         qca->qca_memdump = NULL;
>> +                       mutex_unlock(&qca->hci_memdump_lock);
>>                         return;
>>                 }
>> 
>> @@ -1050,12 +1079,16 @@ static void qca_controller_memdump(struct 
>> work_struct *work)
>>                         kfree(qca->qca_memdump);
>>                         qca->qca_memdump = NULL;
>>                         qca->memdump_state = QCA_MEMDUMP_COLLECTED;
>> +                       clear_bit(QCA_MEMDUMP_COLLECTION, 
>> &qca->flags);
>>                 }
>> +
>> +               mutex_unlock(&qca->hci_memdump_lock);
>>         }
>> 
>>  }
>> 
>> -int qca_controller_memdump_event(struct hci_dev *hdev, struct sk_buff 
>> *skb)
>> +static int qca_controller_memdump_event(struct hci_dev *hdev,
>> +                                       struct sk_buff *skb)
>>  {
>>         struct hci_uart *hu = hci_get_drvdata(hdev);
>>         struct qca_data *qca = hu->priv;
>> @@ -1406,30 +1439,21 @@ static void 
>> qca_wait_for_dump_collection(struct hci_dev *hdev)
>>  {
>>         struct hci_uart *hu = hci_get_drvdata(hdev);
>>         struct qca_data *qca = hu->priv;
>> -       struct qca_memdump_data *qca_memdump = qca->qca_memdump;
>> -       char *memdump_buf = NULL;
>> 
>>         wait_on_bit_timeout(&qca->flags, QCA_MEMDUMP_COLLECTION,
>>                             TASK_UNINTERRUPTIBLE, MEMDUMP_TIMEOUT_MS);
>> 
>>         clear_bit(QCA_MEMDUMP_COLLECTION, &qca->flags);
>> -       if (qca->memdump_state == QCA_MEMDUMP_IDLE) {
>> -               bt_dev_err(hu->hdev, "Clearing the buffers due to 
>> timeout");
>> -               if (qca_memdump)
>> -                       memdump_buf = qca_memdump->memdump_buf_tail;
>> -               vfree(memdump_buf);
>> -               kfree(qca_memdump);
>> -               qca->memdump_state = QCA_MEMDUMP_TIMEOUT;
>> -               del_timer(&qca->memdump_timer);
>> -               cancel_work_sync(&qca->ctrl_memdump_evt);
>> -       }
>>  }
>> 
>>  static void qca_hw_error(struct hci_dev *hdev, u8 code)
>>  {
>>         struct hci_uart *hu = hci_get_drvdata(hdev);
>>         struct qca_data *qca = hu->priv;
>> +       struct qca_memdump_data *qca_memdump = qca->qca_memdump;
>> +       char *memdump_buf = NULL;
>> 
>> +       set_bit(QCA_HW_ERROR_EVENT, &qca->flags);
>>         bt_dev_info(hdev, "mem_dump_status: %d", qca->memdump_state);
>> 
>>         if (qca->memdump_state == QCA_MEMDUMP_IDLE) {
>> @@ -1449,6 +1473,24 @@ static void qca_hw_error(struct hci_dev *hdev, 
>> u8 code)
>>                 bt_dev_info(hdev, "waiting for dump to complete");
>>                 qca_wait_for_dump_collection(hdev);
>>         }
>> +
>> +       if (qca->memdump_state != QCA_MEMDUMP_COLLECTED) {
>> +               bt_dev_err(hu->hdev, "clearing allocated memory due to 
>> memdump timeout");
>> +               mutex_lock(&qca->hci_memdump_lock);
>> +               if (qca_memdump)
>> +                       memdump_buf = qca_memdump->memdump_buf_head;
>> +               vfree(memdump_buf);
>> +               kfree(qca_memdump);
>> +               qca->qca_memdump = NULL;
>> +               qca->memdump_state = QCA_MEMDUMP_TIMEOUT;
>> +               del_timer(&qca->memdump_timer);
>> +               skb_queue_purge(&qca->rx_memdump_q);
>> +               mutex_unlock(&qca->hci_memdump_lock);
>> +               cancel_work_sync(&qca->ctrl_memdump_timeout);
>> +               cancel_work_sync(&qca->ctrl_memdump_evt);
>> +       }
>> +
>> +       clear_bit(QCA_HW_ERROR_EVENT, &qca->flags);
>>  }
>> 
>>  static void qca_cmd_timeout(struct hci_dev *hdev)
>> --
>> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a 
>> member
>> of Code Aurora Forum, hosted by The Linux Foundation
>> 
> 
> Thanks
> Abhishek

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