Peer manager Flash storage is full

[Demetrio Magrin REEL]

I modified the FW "ble_app_uart" using the example "\nRF5_SDK_15.2.0_9412b96\examples\ble_peripheral\ble_app_uart \".
I added the pairing function and "delete_bonds ()".
The "delete_bonds ()" function is activated by pressing the EVAL button "Button 2" at startup.

After many pairing and delete_bonds () tests with the same device (Client) I saw that encrypted communication was no longer active (test by sniffer and wireshark).
I have seen that in these cases JLINK RTT sends me what is shown below.

00> <info> app: Debug logging for UART over RTT started.
00> <info> app: Connected
00> <info> app: Data len is set to 0xF4(244)
00> <info> peer_manager_handler: Connection security failed: role: Peripheral, conn_handle: 0x0, procedure: Bonding, error: 133
00> <info> app: Disconnected
00> <info> app: Connected
00> <info> app: Data len is set to 0xF4(244)
00> <warning> peer_manager_handler: Flash storage is full
00> <info> peer_manager_handler: Attempting to clean flash.
00> <error> peer_manager_handler: There are no peers to delete.
00> <info> peer_manager_handler: Connection secured: role: Peripheral, conn_handle: 0, procedure: Bonding
00> <info> peer_manager_handler: Attempting to clean flash.
00> <error> peer_manager_handler: There are no peers to delete.
00> <info> app: Disconnected
00>

To solve this problem I had to perform the "Erase flash" function through the "SEGGER J-FLASH" program.

Questions:
1) Why the "delete_bonds()" function does not solve this problem ?
2) Is there a way to solve this problem without having to perform the "Erase Flash" function through the SEGGER program ?

Thank you.

BR

Demetrio Magrin

[Demetrio Magrin REEL]

Hi,

I forgot to report the "void pm_evt_handler (pm_evt_t const * p_evt)" function below.

static void pm_evt_handler(pm_evt_t const * p_evt)
{
    pm_handler_on_pm_evt(p_evt);
    pm_handler_flash_clean(p_evt);

    switch (p_evt->evt_id)
    {
        case PM_EVT_PEERS_DELETE_SUCCEEDED:
        {
            advertising_start(false);
        }
        break;
        case PM_EVT_CONN_SEC_CONFIG_REQ:
        {
            //
            // Allow pairing request from an already bonded peer.
            // Note that this will enable a potential attacker to update an existing bond.
            // So there is a trade-off between security and user-friendliness.
            //
            pm_conn_sec_config_t conn_sec_config = { .allow_repairing = true };
            pm_conn_sec_config_reply(m_conn_handle, &conn_sec_config);
        }
        break;
        default:
        break;
    }
}

Thank you.

BR

Demetrio Magrin

[Edvin]

Hello,

Can you check whether fds_gc() is ever called inside your pm_handler_flash_clean() (on line 369 in peer_manager_handler.c)

Best regards,

Edvin

[Demetrio Magrin REEL]

Hello,

For me it is now difficult to reproduce the problem because I deleted the FLASH with SEGGER J-FLASH program.

Analyzing the messages displayed by J-LINK RTT program the code does not execute the "fds_gc()" function because "err_code = NRF_ERROR_NOT_FOUND" -> see msg "There are no peers to delete." and the msg
 "Running flash garbage collection." does not appear in the log from J-Link RTT.

----------------------

00> <info> peer_manager_handler: Attempting to clean flash.
00> <error> peer_manager_handler: There are no peers to delete.

......

void pm_handler_flash_clean(pm_evt_t const * p_pm_evt)
{

        case PM_EVT_STORAGE_FULL:

            if (!flash_cleaning)
            {
                err_code = NRF_SUCCESS;
                NRF_LOG_INFO("Attempting to clean flash.");
                if (!flash_write_after_gc)
                {
                    pm_peer_id_t peer_id_to_delete;
                    err_code = pm_peer_ranks_get(NULL, NULL, &peer_id_to_delete, NULL);
                    if (err_code == NRF_SUCCESS)
                    {
                        NRF_LOG_INFO("Deleting lowest ranked peer (peer_id: %d)", peer_id_to_delete);
                        err_code = pm_peer_delete(peer_id_to_delete);
                        APP_ERROR_CHECK(err_code);
                        flash_write_after_gc = true;
                    }
                    if (err_code == NRF_ERROR_NOT_FOUND)
                    {
                        NRF_LOG_ERROR("There are no peers to delete.");
                    }
                    else if (err_code == NRF_ERROR_NOT_SUPPORTED)
                    {
                        NRF_LOG_WARNING("Peer ranks functionality is disabled, so no peers are deleted.");
                    }
                    else
                    {
                        APP_ERROR_CHECK(err_code);
                    }
                }
                if (err_code == NRF_SUCCESS)
                {
                    err_code = fds_gc();
                    if (err_code == NRF_SUCCESS)
                    {
                        NRF_LOG_DEBUG("Running flash garbage collection.");
                        flash_cleaning = true;
                    }
                    else if (err_code != FDS_ERR_NO_SPACE_IN_QUEUES)
                    {
                        APP_ERROR_CHECK(err_code);
                    }
                }
            }
            break;

---------------------

Questions:
- Is it not correct to execute the "fds_gc()" function in case "PM_EVT_STORAGE_FULL" and "There are no peers to  
  delete." ?

BR

Demetrio Magrin

[Edvin]

Demetrio Magrin REEL said:

- Is it not correct to execute the "fds_gc()" function in case "PM_EVT_STORAGE_FULL" and "There are no peers to  
  delete." ?

 Yes, it is. If the storage is full, and there are no peers to delete, that means that it isn't the peer manager that is full, but the flash. Running a fds_gc() should clean the flash.

The reason why I asked is that "Running flash garbage collection" will only be printed if fds_gc() returns NRF_SUCCESS, so I am not sure whether fds_gc is not called, or if it is called, but not successfully. 

If it is not called, you should call it (you can do that from elsewhere). If it is called, but can't succeed, then it may be because you are in a connection with too low (fast) connection interval. If so, try extending the connection interval, or disconnect before running the fds_gc().

BR,

Edvin

[Demetrio Magrin REEL]

Hello,

I understood what you advised me to do.
To do this I would have to modify the libraries.
I wonder if what I reported is a bug or is normal.

Thank you

BR

Demetrio Magrin