From: Dawei Li set_pte_at@outlook.com
[ Upstream commit 432e25902b9651622578c6248e549297d03caf66 ]
Racing conflict could be: task A task B list_for_each_entry strcmp(h->name)) list_for_each_entry strcmp(h->name) kzalloc kzalloc ...... ..... device_create device_create list_add list_add
The root cause is that task B has no idea about the fact someone else(A) has inserted heap with same name when it calls list_add, so a potential collision occurs.
Fixes: c02a81fba74f ("dma-buf: Add dma-buf heaps framework") Signed-off-by: Dawei Li set_pte_at@outlook.com Acked-by: Andrew Davis afd@ti.com Acked-by: Christian König christian.koenig@amd.com Signed-off-by: Sumit Semwal sumit.semwal@linaro.org Link: https://patchwork.freedesktop.org/patch/msgid/TYCP286MB2323873BBDF88020781FB... Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/dma-buf/dma-heap.c | 28 +++++++++++++++------------- 1 file changed, 15 insertions(+), 13 deletions(-)
diff --git a/drivers/dma-buf/dma-heap.c b/drivers/dma-buf/dma-heap.c index 798f86fcd50f..dcbb023acc45 100644 --- a/drivers/dma-buf/dma-heap.c +++ b/drivers/dma-buf/dma-heap.c @@ -209,18 +209,6 @@ struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info) return ERR_PTR(-EINVAL); }
- /* check the name is unique */ - mutex_lock(&heap_list_lock); - list_for_each_entry(h, &heap_list, list) { - if (!strcmp(h->name, exp_info->name)) { - mutex_unlock(&heap_list_lock); - pr_err("dma_heap: Already registered heap named %s\n", - exp_info->name); - return ERR_PTR(-EINVAL); - } - } - mutex_unlock(&heap_list_lock); - heap = kzalloc(sizeof(*heap), GFP_KERNEL); if (!heap) return ERR_PTR(-ENOMEM); @@ -259,13 +247,27 @@ struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info) err_ret = ERR_CAST(dev_ret); goto err2; } - /* Add heap to the list */ + mutex_lock(&heap_list_lock); + /* check the name is unique */ + list_for_each_entry(h, &heap_list, list) { + if (!strcmp(h->name, exp_info->name)) { + mutex_unlock(&heap_list_lock); + pr_err("dma_heap: Already registered heap named %s\n", + exp_info->name); + err_ret = ERR_PTR(-EINVAL); + goto err3; + } + } + + /* Add heap to the list */ list_add(&heap->list, &heap_list); mutex_unlock(&heap_list_lock);
return heap;
+err3: + device_destroy(dma_heap_class, heap->heap_devt); err2: cdev_del(&heap->heap_cdev); err1: