To avoid race condition and avoid UAF cases, implement kref based queues and protect the below operations using xa lock a. Getting a queue from xarray b. Increment/Decrement it's refcount
Every time some one want to access a queue, always get via amdgpu_userq_get to make sure we have locks in place and get the object if active. A userqueue is destroyed on the last refcount is dropped which typically would be via IOCTL or during fini. Signed-off-by: Sunil Khatri <[email protected]> --- drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c | 85 ++++++++++++++----- drivers/gpu/drm/amd/amdgpu/amdgpu_userq.h | 4 + .../gpu/drm/amd/amdgpu/amdgpu_userq_fence.c | 10 ++- 3 files changed, 76 insertions(+), 23 deletions(-) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c index e07b2082cf25..bd62c95eeaad 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c @@ -461,7 +461,6 @@ static void amdgpu_userq_cleanup(struct amdgpu_usermode_queue *queue, uq_funcs->mqd_destroy(queue); amdgpu_userq_fence_driver_free(queue); /* Use interrupt-safe locking since IRQ handlers may access these XArrays */ - xa_erase_irq(&uq_mgr->userq_xa, queue_id); xa_erase_irq(&adev->userq_doorbell_xa, queue->doorbell_index); queue->userq_mgr = NULL; list_del(&queue->userq_va_list); @@ -470,12 +469,6 @@ static void amdgpu_userq_cleanup(struct amdgpu_usermode_queue *queue, up_read(&adev->reset_domain->sem); } -static struct amdgpu_usermode_queue * -amdgpu_userq_find(struct amdgpu_userq_mgr *uq_mgr, u32 qid) -{ - return xa_load(&uq_mgr->userq_xa, qid); -} - void amdgpu_userq_ensure_ev_fence(struct amdgpu_userq_mgr *uq_mgr, struct amdgpu_eviction_fence_mgr *evf_mgr) @@ -625,22 +618,14 @@ amdgpu_userq_get_doorbell_index(struct amdgpu_userq_mgr *uq_mgr, } static int -amdgpu_userq_destroy(struct drm_file *filp, u32 queue_id) +amdgpu_userq_destroy(struct amdgpu_userq_mgr *uq_mgr, struct amdgpu_usermode_queue *queue, + u32 queue_id) { - struct amdgpu_fpriv *fpriv = filp->driver_priv; - struct amdgpu_userq_mgr *uq_mgr = &fpriv->userq_mgr; struct amdgpu_device *adev = uq_mgr->adev; - struct amdgpu_usermode_queue *queue; int r = 0; cancel_delayed_work_sync(&uq_mgr->resume_work); mutex_lock(&uq_mgr->userq_mutex); - queue = amdgpu_userq_find(uq_mgr, queue_id); - if (!queue) { - drm_dbg_driver(adev_to_drm(uq_mgr->adev), "Invalid queue id to destroy\n"); - mutex_unlock(&uq_mgr->userq_mutex); - return -EINVAL; - } amdgpu_userq_wait_for_last_fence(queue); /* Cancel any pending hang detection work and cleanup */ if (queue->hang_detect_fence) { @@ -680,6 +665,38 @@ amdgpu_userq_destroy(struct drm_file *filp, u32 queue_id) return r; } +struct amdgpu_usermode_queue *amdgpu_userq_get(struct amdgpu_userq_mgr *uq_mgr, u32 qid) +{ + struct amdgpu_usermode_queue *queue; + + xa_lock(&uq_mgr->userq_xa); + queue = xa_load(&uq_mgr->userq_xa, qid); + if (queue) + kref_get(&queue->refcount); + + xa_unlock(&uq_mgr->userq_xa); + return queue; +} + +void amdgpu_userq_put(struct amdgpu_userq_mgr *uq_mgr, u32 qid) +{ + struct amdgpu_usermode_queue *queue; + + xa_lock(&uq_mgr->userq_xa); + queue = xa_load(&uq_mgr->userq_xa, qid); + + if (queue && refcount_dec_and_test(&queue->refcount.refcount)) { + __xa_erase(&uq_mgr->userq_xa, qid); + xa_unlock(&uq_mgr->userq_xa); + + if (amdgpu_userq_destroy(uq_mgr, queue, qid)) + drm_file_err(uq_mgr->file, "Failed to destroy usermode queue\n"); + return; + } + + xa_unlock(&uq_mgr->userq_xa); +} + static int amdgpu_userq_priority_permit(struct drm_file *filp, int priority) { @@ -891,6 +908,8 @@ amdgpu_userq_create(struct drm_file *filp, union drm_amdgpu_userq *args) args->out.queue_id = qid; atomic_inc(&uq_mgr->userq_count[queue->queue_type]); + /* drop this refcount during queue destroy */ + kref_init(&queue->refcount); unlock: mutex_unlock(&uq_mgr->userq_mutex); @@ -985,6 +1004,7 @@ int amdgpu_userq_ioctl(struct drm_device *dev, void *data, struct drm_file *filp) { union drm_amdgpu_userq *args = data; + struct amdgpu_fpriv *fpriv = filp->driver_priv; int r; if (!amdgpu_userq_enabled(dev)) @@ -1001,9 +1021,7 @@ int amdgpu_userq_ioctl(struct drm_device *dev, void *data, break; case AMDGPU_USERQ_OP_FREE: - r = amdgpu_userq_destroy(filp, args->in.queue_id); - if (r) - drm_file_err(filp, "Failed to destroy usermode queue\n"); + amdgpu_userq_put(&fpriv->userq_mgr, args->in.queue_id); break; default: @@ -1023,16 +1041,23 @@ amdgpu_userq_restore_all(struct amdgpu_userq_mgr *uq_mgr) /* Resume all the queues for this process */ xa_for_each(&uq_mgr->userq_xa, queue_id, queue) { + queue = amdgpu_userq_get(uq_mgr, queue_id); + if (!queue) + continue; + if (!amdgpu_userq_buffer_vas_mapped(queue)) { drm_file_err(uq_mgr->file, "trying restore queue without va mapping\n"); queue->state = AMDGPU_USERQ_STATE_INVALID_VA; + amdgpu_userq_put(uq_mgr, queue_id); continue; } r = amdgpu_userq_restore_helper(queue); if (r) ret = r; + + amdgpu_userq_put(uq_mgr, queue_id); } if (ret) @@ -1266,9 +1291,13 @@ amdgpu_userq_evict_all(struct amdgpu_userq_mgr *uq_mgr) amdgpu_userq_detect_and_reset_queues(uq_mgr); /* Try to unmap all the queues in this process ctx */ xa_for_each(&uq_mgr->userq_xa, queue_id, queue) { + queue = amdgpu_userq_get(uq_mgr, queue_id); + if (!queue) + continue; r = amdgpu_userq_preempt_helper(queue); if (r) ret = r; + amdgpu_userq_put(uq_mgr, queue_id); } if (ret) @@ -1301,16 +1330,24 @@ amdgpu_userq_wait_for_signal(struct amdgpu_userq_mgr *uq_mgr) int ret; xa_for_each(&uq_mgr->userq_xa, queue_id, queue) { + queue = amdgpu_userq_get(uq_mgr, queue_id); + if (!queue) + continue; + struct dma_fence *f = queue->last_fence; - if (!f || dma_fence_is_signaled(f)) + if (!f || dma_fence_is_signaled(f)) { + amdgpu_userq_put(uq_mgr, queue_id); continue; + } ret = dma_fence_wait_timeout(f, true, msecs_to_jiffies(100)); if (ret <= 0) { drm_file_err(uq_mgr->file, "Timed out waiting for fence=%llu:%llu\n", f->context, f->seqno); + amdgpu_userq_put(uq_mgr, queue_id); return -ETIMEDOUT; } + amdgpu_userq_put(uq_mgr, queue_id); } return 0; @@ -1368,9 +1405,15 @@ void amdgpu_userq_mgr_fini(struct amdgpu_userq_mgr *userq_mgr) mutex_lock(&userq_mgr->userq_mutex); amdgpu_userq_detect_and_reset_queues(userq_mgr); xa_for_each(&userq_mgr->userq_xa, queue_id, queue) { + queue = amdgpu_userq_get(userq_mgr, queue_id); + if (!queue) + continue; amdgpu_userq_wait_for_last_fence(queue); amdgpu_userq_unmap_helper(queue); amdgpu_userq_cleanup(queue, queue_id); + amdgpu_userq_put(userq_mgr, queue_id); + /* Second put is for the reference taken in this function itself */ + amdgpu_userq_put(userq_mgr, queue_id); } xa_destroy(&userq_mgr->userq_xa); diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.h index f4d1d46ae15e..ec3ce485626d 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.h +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.h @@ -74,6 +74,7 @@ struct amdgpu_usermode_queue { struct dentry *debugfs_queue; struct delayed_work hang_detect_work; struct dma_fence *hang_detect_fence; + struct kref refcount; struct list_head userq_va_list; }; @@ -114,6 +115,9 @@ struct amdgpu_db_info { struct amdgpu_userq_obj *db_obj; }; +struct amdgpu_usermode_queue *amdgpu_userq_get(struct amdgpu_userq_mgr *uq_mgr, u32 qid); +void amdgpu_userq_put(struct amdgpu_userq_mgr *uq_mgr, u32 qid); + int amdgpu_userq_ioctl(struct drm_device *dev, void *data, struct drm_file *filp); int amdgpu_userq_mgr_init(struct amdgpu_userq_mgr *userq_mgr, struct drm_file *file_priv, diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c index 3c30512a6266..ba453361d2b4 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c @@ -521,7 +521,7 @@ int amdgpu_userq_signal_ioctl(struct drm_device *dev, void *data, goto put_gobj_read; /* Retrieve the user queue */ - queue = xa_load(&userq_mgr->userq_xa, args->queue_id); + queue = amdgpu_userq_get(userq_mgr, args->queue_id); if (!queue) { r = -ENOENT; goto put_gobj_write; @@ -612,6 +612,9 @@ int amdgpu_userq_signal_ioctl(struct drm_device *dev, void *data, free_syncobj_handles: kfree(syncobj_handles); + if (queue) + amdgpu_userq_put(userq_mgr, args->queue_id); + return r; } @@ -863,7 +866,7 @@ int amdgpu_userq_wait_ioctl(struct drm_device *dev, void *data, */ num_fences = dma_fence_dedup_array(fences, num_fences); - waitq = xa_load(&userq_mgr->userq_xa, wait_info->waitq_id); + waitq = amdgpu_userq_get(userq_mgr, wait_info->waitq_id); if (!waitq) { r = -EINVAL; goto free_fences; @@ -947,5 +950,8 @@ int amdgpu_userq_wait_ioctl(struct drm_device *dev, void *data, free_syncobj_handles: kfree(syncobj_handles); + if (waitq) + amdgpu_userq_put(userq_mgr, wait_info->waitq_id); + return r; } -- 2.34.1
