Hello,
My static analysis tool reports a possible ABBA deadlock in the amdgpu
driver in Linux 5.10:
amdgpu_debugfs_process_reg_op()
mutex_lock(&adev->grbm_idx_mutex); --> Line 250 (Lock A)
mutex_lock(&adev->pm.mutex); --> Line 259 (Lock B)
amdgpu_set_power_dpm_force_performance_level()
mutex_lock(&adev->pm.mutex); --> Line 381 (Lock B)
pp_dpm_force_performance_level() --> function pointer via
"amdgpu_dpm_force_performance_level()"
pp_dpm_en_umd_pstate()
amdgpu_device_ip_set_clockgating_state()
gfx_v7_0_set_clockgating_state() --> function pointer via
"funcs->set_clockgating_state()"
gfx_v7_0_enable_mgcg()
mutex_lock(&adev->grbm_idx_mutex); --> Line 3646 (Lock A)
mutex_lock(&adev->grbm_idx_mutex); --> Line 3697 (Lock A)
When amdgpu_debugfs_process_reg_op() and
amdgpu_set_power_dpm_force_performance_level() 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
