net: m_can: missing mutexes in tx_work_queue and isr-handler

[Prückl Thomas <T.Prueckl@xxxxxxxxx>]

Hi Chandrasekar,

I'm using the m_can driver with the externals TCAN4550-Q1 can controller (SPI) on an IMX8MN controller.
After some time the driver stops working.

After reviewing the driver (m_can.c) I noticed that there are not mutex locks preventing concurrent access of 
m_can_isr and m_can_tx_work_queue.

After I added mutex_lock in these functions the driver was working fine.

Is the driver really missing the locking or is it done on another level?

Yours sincerely,
Thomas Prueckl