| Message ID | 1643223886-28170-2-git-send-email-quic_deesin@quicinc.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | rpmsg char fixes for race conditions in device reboot | expand |
Hi Deepak, On Thu, Jan 27, 2022 at 12:34:44AM +0530, Deepak Kumar Singh wrote: > Struct device holding cdev should not be freed unless cdev > is not in use. It is possible that user space has opened > char device while kernel has freed the associated struct > device context. > > Mark dev kobj as parent of cdev, so that chardev_add gets > an extra reference to dev. This ensures device context is not > freed until cdev is is not in uses. > --- > drivers/rpmsg/rpmsg_char.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c > index c03a118..72ee101 100644 > --- a/drivers/rpmsg/rpmsg_char.c > +++ b/drivers/rpmsg/rpmsg_char.c > @@ -417,6 +417,7 @@ static int rpmsg_eptdev_create(struct rpmsg_ctrldev *ctrldev, > dev->id = ret; > dev_set_name(dev, "rpmsg%d", ret); > > + cdev_set_parent(&eptdev->cdev, &dev->kobj); > ret = cdev_add(&eptdev->cdev, dev->devt, 1); This issue should have been fixed when cdev_add() was replaced by cdev_device_add(), something you will find on v5.17-rc2. Also, this set is generating checkpatch warnings and as such I will not review the other patches in it. Thanks, Mathieu > if (ret) > goto free_ept_ida; > @@ -533,6 +534,7 @@ static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev) > dev->id = ret; > dev_set_name(&ctrldev->dev, "rpmsg_ctrl%d", ret); > > + cdev_set_parent(&ctrldev->cdev, &dev->kobj); > ret = cdev_add(&ctrldev->cdev, dev->devt, 1); > if (ret) > goto free_ctrl_ida; > -- > 2.7.4 >
On 2/3/2022 11:05 PM, Mathieu Poirier wrote: > Hi Deepak, > > On Thu, Jan 27, 2022 at 12:34:44AM +0530, Deepak Kumar Singh wrote: >> Struct device holding cdev should not be freed unless cdev >> is not in use. It is possible that user space has opened >> char device while kernel has freed the associated struct >> device context. >> >> Mark dev kobj as parent of cdev, so that chardev_add gets >> an extra reference to dev. This ensures device context is not >> freed until cdev is is not in uses. >> --- >> drivers/rpmsg/rpmsg_char.c | 2 ++ >> 1 file changed, 2 insertions(+) >> >> diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c >> index c03a118..72ee101 100644 >> --- a/drivers/rpmsg/rpmsg_char.c >> +++ b/drivers/rpmsg/rpmsg_char.c >> @@ -417,6 +417,7 @@ static int rpmsg_eptdev_create(struct rpmsg_ctrldev *ctrldev, >> dev->id = ret; >> dev_set_name(dev, "rpmsg%d", ret); >> >> + cdev_set_parent(&eptdev->cdev, &dev->kobj); >> ret = cdev_add(&eptdev->cdev, dev->devt, 1); > This issue should have been fixed when cdev_add() was replaced by > cdev_device_add(), something you will find on v5.17-rc2. > > Also, this set is generating checkpatch warnings and as such I will not review > the other patches in it. > > Thanks, > Mathieu Thank you Mathieu for info!! i will recheck other 2 patches for checkpatch warnings. Thanks, Deepak >> if (ret) >> goto free_ept_ida; >> @@ -533,6 +534,7 @@ static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev) >> dev->id = ret; >> dev_set_name(&ctrldev->dev, "rpmsg_ctrl%d", ret); >> >> + cdev_set_parent(&ctrldev->cdev, &dev->kobj); >> ret = cdev_add(&ctrldev->cdev, dev->devt, 1); >> if (ret) >> goto free_ctrl_ida; >> -- >> 2.7.4 >>
diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c index c03a118..72ee101 100644 --- a/drivers/rpmsg/rpmsg_char.c +++ b/drivers/rpmsg/rpmsg_char.c @@ -417,6 +417,7 @@ static int rpmsg_eptdev_create(struct rpmsg_ctrldev *ctrldev, dev->id = ret; dev_set_name(dev, "rpmsg%d", ret); + cdev_set_parent(&eptdev->cdev, &dev->kobj); ret = cdev_add(&eptdev->cdev, dev->devt, 1); if (ret) goto free_ept_ida; @@ -533,6 +534,7 @@ static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev) dev->id = ret; dev_set_name(&ctrldev->dev, "rpmsg_ctrl%d", ret); + cdev_set_parent(&ctrldev->cdev, &dev->kobj); ret = cdev_add(&ctrldev->cdev, dev->devt, 1); if (ret) goto free_ctrl_ida;