On Mon, 9 Oct 2017 09:29:17 +0800
Jia-Ju Bai [off-list ref] wrote:

According to pcmcia.c, the driver may sleep under a spinlock.
The function call paths are:
ssb_pcmcia_read8 (acquire the spinlock)
   select_core_and_segment
     ssb_pcmcia_switch_segment
       ssb_pcmcia_cfg_write
         pcmcia_write_config_byte
           pcmcia_access_config (drivers/pcmcia/pcmcia_resource.c)
             mutex_lock --> may sleep

ssb_pcmcia_read8 (acquire the spinlock)
   select_core_and_segment
     ssb_pcmcia_switch_segment
       sssb_pcmcia_cfg_read
         pcmcia_read_config_byte
           pcmcia_access_config (drivers/pcmcia/pcmcia_resource.c)
             mutex_lock --> may sleep

A possible fix is to use spinlock instead of mutex lock in 
pcmcia_access_config in drivers/pcmcia/pcmcia_resource.c.

These bugs are found by my static analysis tool and my code review.

Thanks for scanning and your resulting bug notification.
I currently don't have the hardware at hand to develop and test a
proper fix for this.
That said, I'm not so sure anymore why bar_lock is a spinlock instead
of a mutex. It might be possible to convert this to mutex.

I will try to look into this.

-- 
Michael