On 10/22/19 3:19 PM, Yang, Philip wrote:
>
> On 2019-10-22 2:40 p.m., Grodzovsky, Andrey wrote:
>> On 10/22/19 2:38 PM, Grodzovsky, Andrey wrote:
>>> On 10/22/19 2:28 PM, Yang, Philip wrote:
>>>> 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->device_stopped 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
>>>> device_stopped flag before sending the updated runlist.
>>> Is there a chance of race condition here where dqm->device_stopped
>>> returns true for some operation (e.g.map_queues_cpsch) but just as it
>>> proceeds GPU reset starts ?
>>>
>>> Andrey
>>
>> Correction -
>>
>> dqm->device_stopped returns FALSE
>>
> No race condition here, dqm->device_stopped is set to FALSE in
> kgd2kfd_post_reset -> dqm->ops.start(), which the last step of
> amdgpu_device_gpu_recover, so it's safe to do map_queue_cpsch.
>
> Regards,
> Philip
Sorry - i was confused by the commit description vs. body - in the
description it's called device_stopped flag while in the body it's
sched_running - probably the description needs to be fixed.
So i mean the switch true->false when GPU reset just begins - you get an
IOCTL to map a queue (if i understood KFD code correctly), check
dqm->sched_running == true and continue, what if right then GPU reset
started due to some issue like job timeout or user triggered reset -
dqm->sched_running becomes false but you already past that checkpoint in
the IOCTL, no ?
Andrey
>
>> Andrey
>>
>>>
>>>> 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@xxxxxxx>
>>>> Signed-off-by: Philip Yang <Philip.Yang@xxxxxxx>
>>>> ---
>>>> drivers/gpu/drm/amd/amdkfd/kfd_chardev.c | 6 +--
>>>> drivers/gpu/drm/amd/amdkfd/kfd_device.c | 5 --
>>>> .../drm/amd/amdkfd/kfd_device_queue_manager.c | 47 +++++++++++++++++--
>>>> .../drm/amd/amdkfd/kfd_device_queue_manager.h | 1 +
>>>> 4 files changed, 46 insertions(+), 13 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
>>>> index d9e36dbf13d5..40d75c39f08e 100644
>>>> --- a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
>>>> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
>>>> @@ -120,13 +120,13 @@ static int kfd_open(struct inode *inode, struct file *filep)
>>>> return -EPERM;
>>>> }
>>>>
>>>> + if (kfd_is_locked())
>>>> + return -EAGAIN;
>>>> +
>>>> process = kfd_create_process(filep);
>>>> if (IS_ERR(process))
>>>> return PTR_ERR(process);
>>>>
>>>> - if (kfd_is_locked())
>>>> - return -EAGAIN;
>>>> -
>>>> dev_dbg(kfd_device, "process %d opened, compat mode (32 bit) - %d\n",
>>>> process->pasid, process->is_32bit_user_mode);
>>>>
>>>> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_device.c b/drivers/gpu/drm/amd/amdkfd/kfd_device.c
>>>> index 8f4b24e84964..4fa8834ce7cb 100644
>>>> --- 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 81fb545cf42c..82e1c6280d13 100644
>>>> --- 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 (!dqm->sched_running)
>>>> + 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 (!dqm->sched_running)
>>>> + 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 2eaea6b04cbe..a8c37e6da027 100644
>>>> --- 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(
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