misc: fastrpc: fix double refcounting on dmabuf (5672ff4d) · Commits · 戴 / test

dma buf refcount has to be done by the driver which is going to use the fd. This driver already does refcount on the dmabuf fd if its actively using it but also does an additional refcounting via extra ioctl. This additional refcount can lead to memory leak in cases where the applications fail to call the ioctl to decrement the refcount. So remove this extra refcount in the ioctl More info of dma buf usage at drivers/dma-buf/dma-buf.c Reported-by:

Mayank Chopra <mak.chopra@codeaurora.org> Reported-by:

Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org> Tested-by:

Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org> Signed-off-by:

Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Link: https://lore.kernel.org/r/20190829092926.12037-5-srinivas.kandagatla@linaro.org Signed-off-by:

Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/fastrpc.c

+0 −25

Original line number	Diff line number	Diff line
		@@ -1198,26 +1198,6 @@ static int fastrpc_device_open(struct inode inode, struct file filp)
		return 0;
		}

		static int fastrpc_dmabuf_free(struct fastrpc_user fl, char __user argp)
		{
		struct dma_buf *buf;
		int info;

		if (copy_from_user(&info, argp, sizeof(info)))
		return -EFAULT;

		buf = dma_buf_get(info);
		if (IS_ERR_OR_NULL(buf))
		return -EINVAL;
		/*
		* one for the last get and other for the ALLOC_DMA_BUFF ioctl
		*/
		dma_buf_put(buf);
		dma_buf_put(buf);

		return 0;
		}

		static int fastrpc_dmabuf_alloc(struct fastrpc_user fl, char __user argp)
		{
		struct fastrpc_alloc_dma_buf bp;
		@@ -1253,8 +1233,6 @@ static int fastrpc_dmabuf_alloc(struct fastrpc_user fl, char __user argp)
		return -EFAULT;
		}

		get_dma_buf(buf->dmabuf);

		return 0;
		}

		@@ -1322,9 +1300,6 @@ static long fastrpc_device_ioctl(struct file *file, unsigned int cmd,
		case FASTRPC_IOCTL_INIT_CREATE:
		err = fastrpc_init_create_process(fl, argp);
		break;
		case FASTRPC_IOCTL_FREE_DMA_BUFF:
		err = fastrpc_dmabuf_free(fl, argp);
		break;
		case FASTRPC_IOCTL_ALLOC_DMA_BUFF:
		err = fastrpc_dmabuf_alloc(fl, argp);
		break;

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