5.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Joakim Zhang <joakim.zhang@xxxxxxxxxxx>
[ Upstream commit b07bc2347672cc8c7293c64499f1488278c5ca3d ]
Reproduced with below sequence:
dma_declare_coherent_memory()->dma_release_coherent_memory()
->dma_declare_coherent_memory()->"return -EBUSY" error
It will return -EBUSY from the dma_assign_coherent_memory()
in dma_declare_coherent_memory(), the reason is that dev->dma_mem
pointer has not been set to NULL after it's freed.
Fixes: cf65a0f6f6ff ("dma-mapping: move all DMA mapping code to kernel/dma")
Signed-off-by: Joakim Zhang <joakim.zhang@xxxxxxxxxxx>
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
kernel/dma/coherent.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/kernel/dma/coherent.c b/kernel/dma/coherent.c
index 2a0c4985f38e..d164b3dbcd93 100644
--- a/kernel/dma/coherent.c
+++ b/kernel/dma/coherent.c
@@ -323,8 +323,10 @@ static int rmem_dma_device_init(struct reserved_mem *rmem, struct device *dev)
static void rmem_dma_device_release(struct reserved_mem *rmem,
struct device *dev)
{
- if (dev)
+ if (dev) {
dev->dma_mem = NULL;
+ dev->dma_mem = NULL;
+ }
}
static const struct reserved_mem_ops rmem_dma_ops = {
--
2.43.0
