As &card->tx_queue_lock is acquired under softirq context along the
following call chain from solos_bh(), other acquisition of the same
lock inside process context should disable at least bh to avoid double
lock.
<deadlock #2>
pclose()
--> spin_lock(&card->tx_queue_lock)
<interrupt>
--> solos_bh()
--> fpga_tx()
--> spin_lock(&card->tx_queue_lock)
This flaw was found by an experimental static analysis tool I am
developing for irq-related deadlock.
To prevent the potential deadlock, the patch uses spin_lock_bh()
on &card->tx_queue_lock under process context code consistently to
prevent the possible deadlock scenario.
Fixes: 213e85d389 ("solos-pci: clean up pclose() function")
Signed-off-by: Chengfeng Ye <dg573847474@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
15319a4e8e