This is a note to let you know that I've just added the patch titled
dma-buf: fix racing conflict of dma_heap_add()
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
dma-buf-fix-racing-conflict-of-dma_heap_add.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 1d0e7066a80030dcb306d2c4e0fef30aa073d547
Author: Dawei Li <set_pte_at@xxxxxxxxxxx>
Date: Sat Nov 5 00:05:36 2022 +0800
dma-buf: fix racing conflict of dma_heap_add()
[ 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@xxxxxxxxxxx>
Acked-by: Andrew Davis <afd@xxxxxx>
Acked-by: Christian König <christian.koenig@xxxxxxx>
Signed-off-by: Sumit Semwal <sumit.semwal@xxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/TYCP286MB2323873BBDF88020781FB986CA3B9@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/dma-buf/dma-heap.c b/drivers/dma-buf/dma-heap.c
index 8f5848aa144f..59d158873f4c 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:
