Download client with SMP dfu over uart crash.

[marcusl97]

Hi, i have been working on getting dfu over uart with smp and mcumgr working on a nrf9160dk.

I kept getting a fatal error: ***** SECURE FAULT ***** Attribution unit violation error where the dumped adress only told me that it came from crc16_sw.c. After a lot of debugging i found out that when CONFIG_SMP_CMD_RETRY_TIME was set too short the download client would time out. Then since img_mgmt_client_upload_init starts a workthread that by default keeps trying to send the data via serial_util.c: mcumgr_serial_tx_pkt() for 15 seconds every CONFIG_SMP_CMD_RETRY_TIME milliseconds. But when the download client fails the data is gone and there isn't any cancellation of the smp transfer or any null check in mcumgr_serial_tx_pkt(). I have fixed it by increasing the CONFIG_SMP_CMD_RETRY_TIME to 1000 and adding a null check in mcumgr_serial_tx_pkt().

[JPHutchins]

Hi, can you try using https://github.com/intercreate/smpmgr? I'll be happy to support.

[JPHutchins]

I'm seeing that SMP_CMD_RETRY_TIME has to do with an SMP client, not a server, so I don't see why it would interact with mcumgr or any other host-side SMP client. Or is this for a coprocessor update, e.g. host SMP client -> primary SMP server -> primary SMP client -> secondary SMP server?

zephyr/subsys/mgmt/mcumgr/smp_client/Kconfig

Lines 24 to 30 in e472fb6

	config SMP_CMD_RETRY_TIME
	int "SMP command re-send period in ms"
	range 100 1000
	default 500
	help
	The time (in ms) which the SMP client will wait for a response before re-sending
	a command.

[marcusl97]

Yes i was trying to send a application update via UART on a nrf9160dk, running smp client on the 9160 and smp server on the 52840 chip. I have moved on to another solution now since i found out that it is not possible to configure an uart for mcumgr during runtime. But i am willing to help test this issue more and try to add a solution.

I can also add that i am working on nrf connect sdk 2.6.1.