From 606091b2f6dcbfbc9c1f948f9525cf0484288054 Mon Sep 17 00:00:00 2001 From: Dawei Li Date: Sat, 5 Nov 2022 00:05:36 +0800 Subject: [PATCH] dma-buf: fix racing conflict of dma_heap_add() MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit [ 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 Acked-by: Andrew Davis Acked-by: Christian König Signed-off-by: Sumit Semwal Link: https://patchwork.freedesktop.org/patch/msgid/TYCP286MB2323873BBDF88020781FB986CA3B9@TYCP286MB2323.JPNP286.PROD.OUTLOOK.COM Signed-off-by: Sasha Levin --- 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 8f5848aa..59d1588 100644 --- a/drivers/dma-buf/dma-heap.c +++ b/drivers/dma-buf/dma-heap.c @@ -233,18 +233,6 @@ 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); @@ -283,13 +271,27 @@ 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: -- 2.7.4