The copy_to_user() function returns the number of bytes remaining to be copied, but we want to return -EFAULT if the copy doesn't complete. Fixes: b754ffbbc0ee ("cxl/mem: Add basic IOCTL interface") Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> --- drivers/cxl/mem.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c index 8331a2fc7667..d73ab363ad71 100644 --- a/drivers/cxl/mem.c +++ b/drivers/cxl/mem.c @@ -745,7 +745,10 @@ static int cxl_send_cmd(struct cxl_memdev *cxlmd, if (rc) return rc; - return copy_to_user(s, &send, sizeof(send)); + if (copy_to_user(s, &send, sizeof(send))) + return -EFAULT; + + return 0; } static long __cxl_memdev_ioctl(struct cxl_memdev *cxlmd, unsigned int cmd, -- 2.30.0