drm/amdgpu: annotate a false positive recursive locking

[  584.110304] ============================================
[  584.110590] WARNING: possible recursive locking detected
[  584.110876] 5.6.0-deli-v5.6-2848-g3f3109b0e75f #1 Tainted: G           OE
[  584.111164] --------------------------------------------
[  584.111456] kworker/38:1/553 is trying to acquire lock:
[  584.111721] ffff9b15ff0a47a0 (&adev->reset_sem){++++}, at: amdgpu_device_gpu_recover+0x262/0x1030 [amdgpu]
[  584.112112]
               but task is already holding lock:
[  584.112673] ffff9b1603d247a0 (&adev->reset_sem){++++}, at: amdgpu_device_gpu_recover+0x262/0x1030 [amdgpu]
[  584.113068]
               other info that might help us debug this:
[  584.113689]  Possible unsafe locking scenario:

[  584.114350]        CPU0
[  584.114685]        ----
[  584.115014]   lock(&adev->reset_sem);
[  584.115349]   lock(&adev->reset_sem);
[  584.115678]
                *** DEADLOCK ***

[  584.116624]  May be due to missing lock nesting notation

[  584.117284] 4 locks held by kworker/38:1/553:
[  584.117616]  #0: ffff9ad635c1d348 ((wq_completion)events){+.+.}, at: process_one_work+0x21f/0x630
[  584.117967]  #1: ffffac708e1c3e58 ((work_completion)(&con->recovery_work)){+.+.}, at: process_one_work+0x21f/0x630
[  584.118358]  #2: ffffffffc1c2a5d0 (&tmp->hive_lock){+.+.}, at: amdgpu_device_gpu_recover+0xae/0x1030 [amdgpu]
[  584.118786]  #3: ffff9b1603d247a0 (&adev->reset_sem){++++}, at: amdgpu_device_gpu_recover+0x262/0x1030 [amdgpu]
[  584.119222]
               stack backtrace:
[  584.119990] CPU: 38 PID: 553 Comm: kworker/38:1 Kdump: loaded Tainted: G           OE     5.6.0-deli-v5.6-2848-g3f3109b0e75f #1
[  584.120782] Hardware name: Supermicro SYS-7049GP-TRT/X11DPG-QT, BIOS 3.1 05/23/2019
[  584.121223] Workqueue: events amdgpu_ras_do_recovery [amdgpu]
[  584.121638] Call Trace:
[  584.122050]  dump_stack+0x98/0xd5
[  584.122499]  __lock_acquire+0x1139/0x16e0
[  584.122931]  ? trace_hardirqs_on+0x3b/0xf0
[  584.123358]  ? cancel_delayed_work+0xa6/0xc0
[  584.123771]  lock_acquire+0xb8/0x1c0
[  584.124197]  ? amdgpu_device_gpu_recover+0x262/0x1030 [amdgpu]
[  584.124599]  down_write+0x49/0x120
[  584.125032]  ? amdgpu_device_gpu_recover+0x262/0x1030 [amdgpu]
[  584.125472]  amdgpu_device_gpu_recover+0x262/0x1030 [amdgpu]
[  584.125910]  ? amdgpu_ras_error_query+0x1b8/0x2a0 [amdgpu]
[  584.126367]  amdgpu_ras_do_recovery+0x159/0x190 [amdgpu]
[  584.126789]  process_one_work+0x29e/0x630
[  584.127208]  worker_thread+0x3c/0x3f0
[  584.127621]  ? __kthread_parkme+0x61/0x90
[  584.128014]  kthread+0x12f/0x150
[  584.128402]  ? process_one_work+0x630/0x630
[  584.128790]  ? kthread_park+0x90/0x90
[  584.129174]  ret_from_fork+0x3a/0x50

Each adev has owned lock_class_key to avoid false positive
recursive locking.

v2:
1. register adev->lock_key into lockdep, otherwise lockdep will
report the below warning

[ 1216.705820] BUG: key ffff890183b647d0 has not been registered!
[ 1216.705924] ------------[ cut here ]------------
[ 1216.705972] DEBUG_LOCKS_WARN_ON(1)
[ 1216.705997] WARNING: CPU: 20 PID: 541 at kernel/locking/lockdep.c:3743 lockdep_init_map+0x150/0x210

v3:
change to use down_write_nest_lock to annotate the false dead-lock
warning.

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dennis Li <Dennis.Li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index 16e23f0533614833440d1876696709a8ea8cf7cf..fe8878761c295d58aab221c90ac9d8796259d8b8 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -4178,12 +4178,16 @@ end:
        return r;
 }
 
-static bool amdgpu_device_lock_adev(struct amdgpu_device *adev)
+static bool amdgpu_device_lock_adev(struct amdgpu_device *adev, struct amdgpu_hive_info *hive)
 {
        if (atomic_cmpxchg(&adev->in_gpu_reset, 0, 1) != 0)
                return false;
 
-       down_write(&adev->reset_sem);
+       if (hive) {
+               down_write_nest_lock(&adev->reset_sem, &hive->hive_lock);
+       } else {
+               down_write(&adev->reset_sem);
+       }
 
        atomic_inc(&adev->gpu_reset_counter);
        switch (amdgpu_asic_reset_method(adev)) {
@@ -4345,7 +4349,7 @@ int amdgpu_device_gpu_recover(struct amdgpu_device *adev,
 
        /* block all schedulers and reset given job's ring */
        list_for_each_entry(tmp_adev, device_list_handle, gmc.xgmi.head) {
-               if (!amdgpu_device_lock_adev(tmp_adev)) {
+               if (!amdgpu_device_lock_adev(tmp_adev, hive)) {
                        DRM_INFO("Bailing on TDR for s_job:%llx, as another already in progress",
                                  job ? job->base.id : -1);
                        r = 0;