Hello,
My static analysis tool reports a possible ABBA deadlock in the dfl
driver in Linux 5.10:
dfl_fpga_cdev_assign_port()
mutex_lock(&cdev->lock); --> Line 1067 (Lock A)
mutex_lock(&pdata->lock); --> Line 1624 (Lock B)
fme_pr()
mutex_lock(&pdata->lock); --> Line 126 (Lock B)
fpga_region_program_fpga()
fpga_bridges_enable()
fpga_bridge_enable()
fme_bridge_enable_set() --> function pointer via
"bridge->br_ops->enable_set()"
dfl_fpga_cdev_find_port()
mutex_lock(&cdev->lock); --> Line 499 (LockA)
When dfl_fpga_cdev_assign_port() and fme_pr() are concurrently executed,
the deadlock can occur.
I am not quite sure whether this possible deadlock is real and how to
fix it if it is real.
Any feedback would be appreciated, thanks
Reported-by: TOTE Robot <oslab@xxxxxxxxxxxxxxx>
Best wishes,
Jia-Ju Bai
