From 11b29c9e25788d0afb2ddb67bcd89424bd25f2f7 Mon Sep 17 00:00:00 2001 From: Felix Kuehling Date: Tue, 2 Oct 2018 18:41:12 -0400 Subject: [PATCH] drm/amdkfd: Fix incorrect use of process->mm MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit This mm_struct pointer should never be dereferenced. If running in a user thread, just use current->mm. If running in a kernel worker use get_task_mm to get a safe reference to the mm_struct. Reviewed-by: Oded Gabbay Acked-by: Christian König Signed-off-by: Felix Kuehling Signed-off-by: Alex Deucher --- .../drm/amd/amdkfd/kfd_device_queue_manager.c | 37 +++++++++++++++---- 1 file changed, 29 insertions(+), 8 deletions(-) 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 ec0d62a16e53..4f22e745df51 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c +++ b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c @@ -358,8 +358,8 @@ static int create_compute_queue_nocpsch(struct device_queue_manager *dqm, struct queue *q, struct qcm_process_device *qpd) { - int retval; struct mqd_manager *mqd_mgr; + int retval; mqd_mgr = dqm->ops.get_mqd_manager(dqm, KFD_MQD_TYPE_COMPUTE); if (!mqd_mgr) @@ -387,8 +387,12 @@ static int create_compute_queue_nocpsch(struct device_queue_manager *dqm, if (!q->properties.is_active) return 0; - retval = mqd_mgr->load_mqd(mqd_mgr, q->mqd, q->pipe, q->queue, - &q->properties, q->process->mm); + if (WARN(q->process->mm != current->mm, + "should only run in user thread")) + retval = -EFAULT; + else + retval = mqd_mgr->load_mqd(mqd_mgr, q->mqd, q->pipe, q->queue, + &q->properties, current->mm); if (retval) goto out_uninit_mqd; @@ -545,9 +549,15 @@ static int update_queue(struct device_queue_manager *dqm, struct queue *q) retval = map_queues_cpsch(dqm); else if (q->properties.is_active && (q->properties.type == KFD_QUEUE_TYPE_COMPUTE || - q->properties.type == KFD_QUEUE_TYPE_SDMA)) - retval = mqd_mgr->load_mqd(mqd_mgr, q->mqd, q->pipe, q->queue, - &q->properties, q->process->mm); + q->properties.type == KFD_QUEUE_TYPE_SDMA)) { + if (WARN(q->process->mm != current->mm, + "should only run in user thread")) + retval = -EFAULT; + else + retval = mqd_mgr->load_mqd(mqd_mgr, q->mqd, + q->pipe, q->queue, + &q->properties, current->mm); + } out_unlock: dqm_unlock(dqm); @@ -653,6 +663,7 @@ out: static int restore_process_queues_nocpsch(struct device_queue_manager *dqm, struct qcm_process_device *qpd) { + struct mm_struct *mm = NULL; struct queue *q; struct mqd_manager *mqd_mgr; struct kfd_process_device *pdd; @@ -686,6 +697,15 @@ static int restore_process_queues_nocpsch(struct device_queue_manager *dqm, kfd_flush_tlb(pdd); } + /* Take a safe reference to the mm_struct, which may otherwise + * disappear even while the kfd_process is still referenced. + */ + mm = get_task_mm(pdd->process->lead_thread); + if (!mm) { + retval = -EFAULT; + goto out; + } + /* activate all active queues on the qpd */ list_for_each_entry(q, &qpd->queues_list, list) { if (!q->properties.is_evicted) @@ -700,14 +720,15 @@ static int restore_process_queues_nocpsch(struct device_queue_manager *dqm, q->properties.is_evicted = false; q->properties.is_active = true; retval = mqd_mgr->load_mqd(mqd_mgr, q->mqd, q->pipe, - q->queue, &q->properties, - q->process->mm); + q->queue, &q->properties, mm); if (retval) goto out; dqm->queue_count++; } qpd->evicted = 0; out: + if (mm) + mmput(mm); dqm_unlock(dqm); return retval; } -- 2.30.2