[PATCH] usb: f_fs-aio-simple: add NULL checks for malloc calls

[PATCH] usb: f_fs-aio-simple: add NULL checks for malloc calls

[longlong yan]

Add NULL checks for the return values of malloc() in the aio_simple
FFS example application. If any of the four malloc calls (buf_in,
buf_out, iocb_in, iocb_out) fails, the subsequent code would
dereference NULL pointers in the main loop.

Since free(NULL) is safe, the error path frees all four buffers
unconditionally, then cleans up the remaining resources (io context,
endpoint file descriptors) consistent with the existing cleanup at
the end of the function.

Signed-off-by: longlong yan <yanlonglong@kylinos.cn>
---
 .../ffs-aio-example/simple/device_app/aio_simple.c  | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/tools/usb/ffs-aio-example/simple/device_app/aio_simple.c b/tools/usb/ffs-aio-example/simple/device_app/aio_simple.c
index 96616eb4600b..07ca1f136ad7 100644
--- a/tools/usb/ffs-aio-example/simple/device_app/aio_simple.c
+++ b/tools/usb/ffs-aio-example/simple/device_app/aio_simple.c
@@ -294,6 +294,19 @@ int main(int argc, char *argv[])
 	iocb_in = malloc(sizeof(*iocb_in));
 	iocb_out = malloc(sizeof(*iocb_out));
 
+	if (!buf_in || !buf_out || !iocb_in || !iocb_out) {
+		perror("malloc");
+		free(buf_in);
+		free(buf_out);
+		free(iocb_in);
+		free(iocb_out);
+		io_destroy(ctx);
+		for (i = 0; i < 2; ++i)
+			close(ep[i]);
+		close(ep0);
+		return 1;
+	}
+
 	while (1) {
 		FD_ZERO(&rfds);
 		FD_SET(ep0, &rfds);
-- 
2.43.0

Re: [PATCH] usb: f_fs-aio-simple: add NULL checks for malloc calls

[Greg KH]

On Mon, Aug 17, 2026 at 02:27:56PM +0800, longlong yan wrote:
> Add NULL checks for the return values of malloc() in the aio_simple
> FFS example application. If any of the four malloc calls (buf_in,
> buf_out, iocb_in, iocb_out) fails, the subsequent code would
> dereference NULL pointers in the main loop.
> 
> Since free(NULL) is safe, the error path frees all four buffers
> unconditionally, then cleans up the remaining resources (io context,
> endpoint file descriptors) consistent with the existing cleanup at
> the end of the function.
> 
> Signed-off-by: longlong yan <yanlonglong@kylinos.cn>
> ---
>  .../ffs-aio-example/simple/device_app/aio_simple.c  | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/tools/usb/ffs-aio-example/simple/device_app/aio_simple.c b/tools/usb/ffs-aio-example/simple/device_app/aio_simple.c
> index 96616eb4600b..07ca1f136ad7 100644
> --- a/tools/usb/ffs-aio-example/simple/device_app/aio_simple.c
> +++ b/tools/usb/ffs-aio-example/simple/device_app/aio_simple.c
> @@ -294,6 +294,19 @@ int main(int argc, char *argv[])
>  	iocb_in = malloc(sizeof(*iocb_in));
>  	iocb_out = malloc(sizeof(*iocb_out));
>  
> +	if (!buf_in || !buf_out || !iocb_in || !iocb_out) {
> +		perror("malloc");
> +		free(buf_in);
> +		free(buf_out);
> +		free(iocb_in);
> +		free(iocb_out);
> +		io_destroy(ctx);
> +		for (i = 0; i < 2; ++i)
> +			close(ep[i]);
> +		close(ep0);
> +		return 1;
> +	}

It's userspace, why not just return an error and let the kernel clean up
the memory automatically?

Or better yet, just have a goto to jump to the end of the function where
all of this code already lives?

How did you find this problem?  How was it tested?

thanks,

greg k-h