From: Vitaly Prosyak <[email protected]> The issue started to appear after the following commit 11b3b9f461c5c4f700f6c8da202fcc2fd6418e1f (scheduler to variable number of run-queues). The scheduler flag ready (ring->sched.ready) could not be used to validate multiple scenarios, for example, check job is running, gpu_reset, PCI errors etc. The reason is that after GPU reset, the flag is set to true unconditionally even for those rings with an uninitialized scheduler. As a result, we called drm_sched_stop, drm_sched_start for the uninitialized schedule and NULL pointer dereference is occured. For example, the following occurs on Navi10 during GPU reset:
[ 354.231044] Hardware name: TYAN B8021G88V2HR-2T/S8021GM2NR-2T, BIOS V1.03.B10 04/01/2019 [ 354.239152] Workqueue: amdgpu-reset-dev drm_sched_job_timedout [gpu_sched] [ 354.246047] RIP: 0010:__flush_work.isra.0+0x23a/0x250 [ 354.251110] Code: 8b 04 25 40 2e 03 00 48 89 44 24 40 48 8b 73 40 8b 4b 30 e9 f9 fe ff ff 40 30 f6 4c 8b 36 e9 37 fe ff ff 0f 0b e9 3a ff ff ff <0f> 0b e9 33 ff ff ff 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 [ 354.269876] RSP: 0018:ffffb234c00e3c20 EFLAGS: 00010246 [ 354.275121] RAX: 0000000000000011 RBX: ffff9796d9796de0 RCX: 0000000000000000 [ 354.282271] RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff9796d9796de0 [ 354.289420] RBP: ffff9796d9796de0 R08: ffff977780401940 R09: ffffffffa1a5c620 [ 354.296570] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 [ 354.303720] R13: 0000000000000001 R14: ffff9796d97905c8 R15: ffff9796d9790230 [ 354.310868] FS: 0000000000000000(0000) GS:ffff97865f040000(0000) knlGS:0000000000000000 [ 354.318963] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 354.324717] CR2: 00007fd5341fca50 CR3: 0000002c27a22000 CR4: 00000000003506f0 [ 354.324717] CR2: 00007fd5341fca50 CR3: 0000002c27a22000 CR4: 00000000003506f0 [ 354.331859] Call Trace: [ 354.334320] <TASK> [ 354.336433] ? __flush_work.isra.0+0x23a/0x250 [ 354.340891] ? __warn+0x81/0x130 [ 354.344139] ? __flush_work.isra.0+0x23a/0x250 [ 354.348594] ? report_bug+0x171/0x1a0 [ 354.352279] ? handle_bug+0x3c/0x80 [ 354.355787] ? exc_invalid_op+0x17/0x70 [ 354.359635] ? asm_exc_invalid_op+0x1a/0x20 [ 354.363844] ? __flush_work.isra.0+0x23a/0x250 [ 354.368307] ? srso_return_thunk+0x5/0x5f [ 354.372331] ? srso_return_thunk+0x5/0x5f [ 354.376351] ? desc_read_finalized_seq+0x1f/0x70 [ 354.380982] ? srso_return_thunk+0x5/0x5f [ 354.385011] ? _prb_read_valid+0x20e/0x280 [ 354.389130] __cancel_work_timer+0xd3/0x160 [ 354.393333] drm_sched_stop+0x46/0x1f0 [gpu_sched] [ 354.398143] amdgpu_device_gpu_recover+0x318/0xca0 [amdgpu] [ 354.403995] ? __drm_err+0x1/0x70 [drm] [ 354.407884] amdgpu_job_timedout+0x151/0x240 [amdgpu] [ 354.413279] drm_sched_job_timedout+0x76/0x100 [gpu_sched] [ 354.418787] process_one_work+0x174/0x340 [ 354.422816] worker_thread+0x27b/0x3a0 [ 354.426586] ? __pfx_worker_thread+0x10/0x10 [ 354.430874] kthread+0xe8/0x120 [ 354.434030] ? __pfx_kthread+0x10/0x10 [ 354.437790] ret_from_fork+0x34/0x50 [ 354.441377] ? __pfx_kthread+0x10/0x10 [ 354.445139] ret_from_fork_asm+0x1b/0x30 [ 354.449079] </TASK> [ 354.451285] ---[ end trace 0000000000000000 ]--- [ 354.455917] BUG: kernel NULL pointer dereference, address: 0000000000000008 [ 354.462883] #PF: supervisor read access in kernel mode [ 354.468029] #PF: error_code(0x0000) - not-present page [ 354.473167] PGD 0 P4D 0 [ 354.475705] Oops: 0000 [#1] PREEMPT SMP NOPTI [ 354.480066] CPU: 1 PID: 11 Comm: kworker/u64:0 Tainted: G W 6.7.0-991912.1.zuul.e7596ab24dae4bb686e58b0f1e7842da #1 [ 354.491883] Hardware name: TYAN B8021G88V2HR-2T/S8021GM2NR-2T, BIOS V1.03.B10 04/01/2019 [ 354.499976] Workqueue: amdgpu-reset-dev drm_sched_job_timedout [gpu_sched] [ 354.506855] RIP: 0010:drm_sched_stop+0x61/0x1f0 [gpu_sched] The solution is every place where we check the ready flag and check for ring->no_scheduler. The ready flag serves the purpose in case an initialization is failed, like starting the worker thread, etc. Cc: Alex Deucher <[email protected]> Cc: Christian Koenig <[email protected]> Signed-off-by: Vitaly Prosyak <[email protected]> --- .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_arcturus.c | 2 ++ drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c | 6 +++--- drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 14 ++++++++------ 3 files changed, 13 insertions(+), 9 deletions(-) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_arcturus.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_arcturus.c index 899e31e3a5e8..70bbf602df34 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_arcturus.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_arcturus.c @@ -292,6 +292,8 @@ static int suspend_resume_compute_scheduler(struct amdgpu_device *adev, bool sus if (!(ring && drm_sched_wqueue_ready(&ring->sched))) continue; + if (ring->no_scheduler) + continue; /* stop secheduler and drain ring. */ if (suspend) { diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c index e485dd3357c6..35132aa2c0f4 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c @@ -1678,7 +1678,7 @@ static int amdgpu_debugfs_test_ib_show(struct seq_file *m, void *unused) for (i = 0; i < AMDGPU_MAX_RINGS; i++) { struct amdgpu_ring *ring = adev->rings[i]; - if (!ring || !drm_sched_wqueue_ready(&ring->sched)) + if (!ring || ring->no_scheduler || !drm_sched_wqueue_ready(&ring->sched)) continue; drm_sched_wqueue_stop(&ring->sched); } @@ -1694,7 +1694,7 @@ static int amdgpu_debugfs_test_ib_show(struct seq_file *m, void *unused) for (i = 0; i < AMDGPU_MAX_RINGS; i++) { struct amdgpu_ring *ring = adev->rings[i]; - if (!ring || !drm_sched_wqueue_ready(&ring->sched)) + if (!ring || ring->no_scheduler || !drm_sched_wqueue_ready(&ring->sched)) continue; drm_sched_wqueue_start(&ring->sched); } @@ -1916,7 +1916,7 @@ static int amdgpu_debugfs_ib_preempt(void *data, u64 val) ring = adev->rings[val]; - if (!ring || !ring->funcs->preempt_ib || + if (!ring || !ring->funcs->preempt_ib || ring->no_scheduler || !drm_sched_wqueue_ready(&ring->sched)) return -EINVAL; diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c index 2df14f0e79d8..894b657df1d3 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c @@ -5052,7 +5052,7 @@ bool amdgpu_device_has_job_running(struct amdgpu_device *adev) for (i = 0; i < AMDGPU_MAX_RINGS; ++i) { struct amdgpu_ring *ring = adev->rings[i]; - if (!ring || !drm_sched_wqueue_ready(&ring->sched)) + if (!ring || ring->no_scheduler || !drm_sched_wqueue_ready(&ring->sched)) continue; spin_lock(&ring->sched.job_list_lock); @@ -5191,8 +5191,10 @@ int amdgpu_device_pre_asic_reset(struct amdgpu_device *adev, for (i = 0; i < AMDGPU_MAX_RINGS; ++i) { struct amdgpu_ring *ring = adev->rings[i]; - if (!ring || !drm_sched_wqueue_ready(&ring->sched)) + if (!ring || ring->no_scheduler || !drm_sched_wqueue_ready(&ring->sched)) continue; + if (ring->no_scheduler) + continue; /* Clear job fence from fence drv to avoid force_completion * leave NULL and vm flush fence in fence drv @@ -5658,7 +5660,7 @@ int amdgpu_device_gpu_recover(struct amdgpu_device *adev, for (i = 0; i < AMDGPU_MAX_RINGS; ++i) { struct amdgpu_ring *ring = tmp_adev->rings[i]; - if (!ring || !drm_sched_wqueue_ready(&ring->sched)) + if (!ring || ring->no_scheduler || !drm_sched_wqueue_ready(&ring->sched)) continue; drm_sched_stop(&ring->sched, job ? &job->base : NULL); @@ -5727,7 +5729,7 @@ int amdgpu_device_gpu_recover(struct amdgpu_device *adev, for (i = 0; i < AMDGPU_MAX_RINGS; ++i) { struct amdgpu_ring *ring = tmp_adev->rings[i]; - if (!ring || !drm_sched_wqueue_ready(&ring->sched)) + if (!ring || ring->no_scheduler || !drm_sched_wqueue_ready(&ring->sched)) continue; drm_sched_start(&ring->sched, true); @@ -6082,7 +6084,7 @@ pci_ers_result_t amdgpu_pci_error_detected(struct pci_dev *pdev, pci_channel_sta for (i = 0; i < AMDGPU_MAX_RINGS; ++i) { struct amdgpu_ring *ring = adev->rings[i]; - if (!ring || !drm_sched_wqueue_ready(&ring->sched)) + if (!ring || ring->no_scheduler || !drm_sched_wqueue_ready(&ring->sched)) continue; drm_sched_stop(&ring->sched, NULL); @@ -6224,7 +6226,7 @@ void amdgpu_pci_resume(struct pci_dev *pdev) for (i = 0; i < AMDGPU_MAX_RINGS; ++i) { struct amdgpu_ring *ring = adev->rings[i]; - if (!ring || !drm_sched_wqueue_ready(&ring->sched)) + if (!ring || ring->no_scheduler || !drm_sched_wqueue_ready(&ring->sched)) continue; drm_sched_start(&ring->sched, true); -- 2.25.1
