4.19-stable review patch. If anyone has any objections, please let me know.
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From: Joakim Zhang joakim.zhang@cixtech.com
[ 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@cixtech.com Signed-off-by: Christoph Hellwig hch@lst.de Signed-off-by: Sasha Levin sashal@kernel.org --- 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 597d40893862..4c7ffd094a57 100644 --- a/kernel/dma/coherent.c +++ b/kernel/dma/coherent.c @@ -369,8 +369,10 @@ 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 = {