Hello,

Could you please provide the feedback to my previous report? Thanks a lot :)

Best wishes, Jia-Ju Bai

On 2021/9/15 17:39, Jia-Ju Bai wrote:

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@tsinghua.edu.cn

Best wishes, Jia-Ju Bai