On 20/04/2020 06:44, Xiyu Yang wrote:
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 <xiyuyang19@xxxxxxxxxxxx> Signed-off-by: Xin Tan <tanxin.ctf@xxxxxxxxx> --- 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 08d1bbbebf2d..e84b4fb493d6 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;
Thanks for spotting that! Signed-off-by: Ian Abbott <abbotti@xxxxxxxxx> -- -=( Ian Abbott <abbotti@xxxxxxxxx> || Web: www.mev.co.uk )=- -=( MEV Ltd. is a company registered in England & Wales. )=- -=( Registered number: 02862268. Registered address: )=- -=( 15 West Park Road, Bramhall, STOCKPORT, SK7 3JZ, UK. )=- _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
