From 332e0e17ad49e084b7db670ef43b5eb59abd9e34 Mon Sep 17 00:00:00 2001 From: Xiyu Yang Date: Mon, 20 Apr 2020 13:44:16 +0800 Subject: [PATCH] staging: comedi: Fix comedi_device refcnt leak in comedi_open comedi_open() invokes comedi_dev_get_from_minor(), which returns a reference of the COMEDI device to "dev" with increased refcount. When comedi_open() returns, "dev" becomes invalid, so the refcount should be decreased to keep refcount balanced. The reference counting issue happens in one exception handling path of comedi_open(). When "cfp" allocation is failed, the refcnt increased by comedi_dev_get_from_minor() is not decreased, causing a refcnt leak. Fix this issue by calling comedi_dev_put() on this error path when "cfp" allocation is failed. Fixes: 20f083c07565 ("staging: comedi: prepare support for per-file read and write subdevices") Signed-off-by: Xiyu Yang Cc: stable Signed-off-by: Xin Tan Signed-off-by: Ian Abbott Link: https://lore.kernel.org/r/1587361459-83622-1-git-send-email-xiyuyang19@fudan.edu.cn Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/comedi_fops.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c index 08d1bbb..e84b4fb 100644 --- a/drivers/staging/comedi/comedi_fops.c +++ b/drivers/staging/comedi/comedi_fops.c @@ -2725,8 +2725,10 @@ static int comedi_open(struct inode *inode, struct file *file) } cfp = kzalloc(sizeof(*cfp), GFP_KERNEL); - if (!cfp) + if (!cfp) { + comedi_dev_put(dev); return -ENOMEM; + } cfp->dev = dev; -- 2.7.4