From 4985e507e0b99078b81d8691a99ff6b42084046e Mon Sep 17 00:00:00 2001 From: Joakim Zhang Date: Thu, 14 Dec 2023 16:25:26 +0800 Subject: [PATCH] dma-mapping: clear dev->dma_mem to NULL after freeing it [ 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 Signed-off-by: Christoph Hellwig Signed-off-by: Sasha Levin --- 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 = {