drm/amdkfd: don't use dqm lock during device reset/suspend/resume

If device reset/suspend/resume failed for some reason, dqm lock is
hold forever and this causes deadlock. Below is a kernel backtrace when
application open kfd after suspend/resume failed.

Instead of holding dqm lock in pre_reset and releasing dqm lock in
post_reset, add dqm->sched_running flag which is modified in
dqm->ops.start and dqm->ops.stop. The flag doesn't need lock protection
because write/read are all inside dqm lock.

For HWS case, map_queues_cpsch and unmap_queues_cpsch checks
sched_running flag before sending the updated runlist.

v2: For no-HWS case, when device is stopped, don't call
load/destroy_mqd for eviction, restore and create queue, and avoid
debugfs dump hdqs.

Backtrace of dqm lock deadlock:

[Thu Oct 17 16:43:37 2019] INFO: task rocminfo:3024 blocked for more
than 120 seconds.
[Thu Oct 17 16:43:37 2019]       Not tainted
5.0.0-rc1-kfd-compute-rocm-dkms-no-npi-1131 #1
[Thu Oct 17 16:43:37 2019] "echo 0 >
/proc/sys/kernel/hung_task_timeout_secs" disables this message.
[Thu Oct 17 16:43:37 2019] rocminfo        D    0  3024   2947
0x80000000
[Thu Oct 17 16:43:37 2019] Call Trace:
[Thu Oct 17 16:43:37 2019]  ? __schedule+0x3d9/0x8a0
[Thu Oct 17 16:43:37 2019]  schedule+0x32/0x70
[Thu Oct 17 16:43:37 2019]  schedule_preempt_disabled+0xa/0x10
[Thu Oct 17 16:43:37 2019]  __mutex_lock.isra.9+0x1e3/0x4e0
[Thu Oct 17 16:43:37 2019]  ? __call_srcu+0x264/0x3b0
[Thu Oct 17 16:43:37 2019]  ? process_termination_cpsch+0x24/0x2f0
[amdgpu]
[Thu Oct 17 16:43:37 2019]  process_termination_cpsch+0x24/0x2f0
[amdgpu]
[Thu Oct 17 16:43:37 2019]
kfd_process_dequeue_from_all_devices+0x42/0x60 [amdgpu]
[Thu Oct 17 16:43:37 2019]  kfd_process_notifier_release+0x1be/0x220
[amdgpu]
[Thu Oct 17 16:43:37 2019]  __mmu_notifier_release+0x3e/0xc0
[Thu Oct 17 16:43:37 2019]  exit_mmap+0x160/0x1a0
[Thu Oct 17 16:43:37 2019]  ? __handle_mm_fault+0xba3/0x1200
[Thu Oct 17 16:43:37 2019]  ? exit_robust_list+0x5a/0x110
[Thu Oct 17 16:43:37 2019]  mmput+0x4a/0x120
[Thu Oct 17 16:43:37 2019]  do_exit+0x284/0xb20
[Thu Oct 17 16:43:37 2019]  ? handle_mm_fault+0xfa/0x200
[Thu Oct 17 16:43:37 2019]  do_group_exit+0x3a/0xa0
[Thu Oct 17 16:43:37 2019]  __x64_sys_exit_group+0x14/0x20
[Thu Oct 17 16:43:37 2019]  do_syscall_64+0x4f/0x100
[Thu Oct 17 16:43:37 2019]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

Suggested-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Philip Yang <Philip.Yang@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_device.c b/drivers/gpu/drm/amd/amdkfd/kfd_device.c
index 8f4b24e84964b7eae692d8e2742b7e1e58730424..4fa8834ce7cb011f388e2c5cb5b62355a0c116c7 100644 (file)
--- a/drivers/gpu/drm/amd/amdkfd/kfd_device.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_device.c
@@ -730,9 +730,6 @@ int kgd2kfd_pre_reset(struct kfd_dev *kfd)
                return 0;
        kgd2kfd_suspend(kfd);
 
-       /* hold dqm->lock to prevent further execution*/
-       dqm_lock(kfd->dqm);
-
        kfd_signal_reset_event(kfd);
        return 0;
 }
@@ -750,8 +747,6 @@ int kgd2kfd_post_reset(struct kfd_dev *kfd)
        if (!kfd->init_complete)
                return 0;
 
-       dqm_unlock(kfd->dqm);
-
        ret = kfd_resume(kfd);
        if (ret)
                return ret;

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
index 81fb545cf42c6f90e79a374ba2eebde5c7df89ec..984c2f2b24b607dcc40848844796234694004f08 100644 (file)
--- a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
@@ -340,6 +340,10 @@ static int create_queue_nocpsch(struct device_queue_manager *dqm,
        mqd_mgr->init_mqd(mqd_mgr, &q->mqd, q->mqd_mem_obj,
                                &q->gart_mqd_addr, &q->properties);
        if (q->properties.is_active) {
+               if (!dqm->sched_running) {
+                       WARN_ONCE(1, "Load non-HWS mqd while stopped\n");
+                       goto add_queue_to_list;
+               }
 
                if (WARN(q->process->mm != current->mm,
                                        "should only run in user thread"))
@@ -351,6 +355,7 @@ static int create_queue_nocpsch(struct device_queue_manager *dqm,
                        goto out_free_mqd;
        }
 
+add_queue_to_list:
        list_add(&q->list, &qpd->queues_list);
        qpd->queue_count++;
        if (q->properties.is_active)
@@ -458,6 +463,11 @@ static int destroy_queue_nocpsch_locked(struct device_queue_manager *dqm,
 
        deallocate_doorbell(qpd, q);
 
+       if (!dqm->sched_running) {
+               WARN_ONCE(1, "Destroy non-HWS queue while stopped\n");
+               return 0;
+       }
+
        retval = mqd_mgr->destroy_mqd(mqd_mgr, q->mqd,
                                KFD_PREEMPT_TYPE_WAVEFRONT_RESET,
                                KFD_UNMAP_LATENCY_MS,
@@ -533,6 +543,12 @@ static int update_queue(struct device_queue_manager *dqm, struct queue *q)
                   (q->properties.type == KFD_QUEUE_TYPE_COMPUTE ||
                    q->properties.type == KFD_QUEUE_TYPE_SDMA ||
                    q->properties.type == KFD_QUEUE_TYPE_SDMA_XGMI)) {
+
+               if (!dqm->sched_running) {
+                       WARN_ONCE(1, "Update non-HWS queue while stopped\n");
+                       goto out_unlock;
+               }
+
                retval = mqd_mgr->destroy_mqd(mqd_mgr, q->mqd,
                                KFD_PREEMPT_TYPE_WAVEFRONT_DRAIN,
                                KFD_UNMAP_LATENCY_MS, q->pipe, q->queue);
@@ -602,6 +618,11 @@ static int evict_process_queues_nocpsch(struct device_queue_manager *dqm,
                mqd_mgr = dqm->mqd_mgrs[get_mqd_type_from_queue_type(
                                q->properties.type)];
                q->properties.is_active = false;
+               dqm->queue_count--;
+
+               if (WARN_ONCE(!dqm->sched_running, "Evict when stopped\n"))
+                       continue;
+
                retval = mqd_mgr->destroy_mqd(mqd_mgr, q->mqd,
                                KFD_PREEMPT_TYPE_WAVEFRONT_DRAIN,
                                KFD_UNMAP_LATENCY_MS, q->pipe, q->queue);
@@ -610,7 +631,6 @@ static int evict_process_queues_nocpsch(struct device_queue_manager *dqm,
                         * maintain a consistent eviction state
                         */
                        ret = retval;
-               dqm->queue_count--;
        }
 
 out:
@@ -711,6 +731,11 @@ static int restore_process_queues_nocpsch(struct device_queue_manager *dqm,
                mqd_mgr = dqm->mqd_mgrs[get_mqd_type_from_queue_type(
                                q->properties.type)];
                q->properties.is_active = true;
+               dqm->queue_count++;
+
+               if (WARN_ONCE(!dqm->sched_running, "Restore when stopped\n"))
+                       continue;
+
                retval = mqd_mgr->load_mqd(mqd_mgr, q->mqd, q->pipe,
                                       q->queue, &q->properties, mm);
                if (retval && !ret)
@@ -718,7 +743,6 @@ static int restore_process_queues_nocpsch(struct device_queue_manager *dqm,
                         * maintain a consistent eviction state
                         */
                        ret = retval;
-               dqm->queue_count++;
        }
        qpd->evicted = 0;
 out:
@@ -915,7 +939,8 @@ static int start_nocpsch(struct device_queue_manager *dqm)
        
        if (dqm->dev->device_info->asic_family == CHIP_HAWAII)
                return pm_init(&dqm->packets, dqm);
-       
+       dqm->sched_running = true;
+
        return 0;
 }
 
@@ -923,7 +948,8 @@ static int stop_nocpsch(struct device_queue_manager *dqm)
 {
        if (dqm->dev->device_info->asic_family == CHIP_HAWAII)
                pm_uninit(&dqm->packets);
-       
+       dqm->sched_running = false;
+
        return 0;
 }
 
@@ -1074,6 +1100,7 @@ static int start_cpsch(struct device_queue_manager *dqm)
        dqm_lock(dqm);
        /* clear hang status when driver try to start the hw scheduler */
        dqm->is_hws_hang = false;
+       dqm->sched_running = true;
        execute_queues_cpsch(dqm, KFD_UNMAP_QUEUES_FILTER_DYNAMIC_QUEUES, 0);
        dqm_unlock(dqm);
 
@@ -1089,6 +1116,7 @@ static int stop_cpsch(struct device_queue_manager *dqm)
 {
        dqm_lock(dqm);
        unmap_queues_cpsch(dqm, KFD_UNMAP_QUEUES_FILTER_ALL_QUEUES, 0);
+       dqm->sched_running = false;
        dqm_unlock(dqm);
 
        kfd_gtt_sa_free(dqm->dev, dqm->fence_mem);
@@ -1275,9 +1303,10 @@ static int map_queues_cpsch(struct device_queue_manager *dqm)
 {
        int retval;
 
+       if (!dqm->sched_running)
+               return 0;
        if (dqm->queue_count <= 0 || dqm->processes_count <= 0)
                return 0;
-
        if (dqm->active_runlist)
                return 0;
 
@@ -1299,6 +1328,8 @@ static int unmap_queues_cpsch(struct device_queue_manager *dqm,
 {
        int retval = 0;
 
+       if (!dqm->sched_running)
+               return 0;
        if (dqm->is_hws_hang)
                return -EIO;
        if (!dqm->active_runlist)
@@ -1903,6 +1934,12 @@ int dqm_debugfs_hqds(struct seq_file *m, void *data)
        int pipe, queue;
        int r = 0;
 
+       if (!dqm->sched_running) {
+               seq_printf(m, " Device is stopped\n");
+
+               return 0;
+       }
+
        r = dqm->dev->kfd2kgd->hqd_dump(dqm->dev->kgd,
                                        KFD_CIK_HIQ_PIPE, KFD_CIK_HIQ_QUEUE,
                                        &dump, &n_regs);

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.h b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.h
index 2eaea6b04cbe4d655bd0afc5445ba4b700fdc934..a8c37e6da02785553839c9b9963fccf99ffa4c62 100644 (file)
--- a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.h
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.h
@@ -201,6 +201,7 @@ struct device_queue_manager {
        bool                    is_hws_hang;
        struct work_struct      hw_exception_work;
        struct kfd_mem_obj      hiq_sdma_mqd;
+       bool                    sched_running;
 };
 
 void device_queue_manager_init_cik(