LinuxTV Patchwork cec: mark devnode as registered before actually registering it

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Submitter Hans Verkuil
Date May 10, 2019, 3:15 p.m.
Message ID <b1c054d1-e041-b518-96bd-d53003d02804@xs4all.nl>
Download mbox | patch
Permalink /patch/56104/
State Accepted
Delegated to: Hans Verkuil
Headers show

Comments

Hans Verkuil - May 10, 2019, 3:15 p.m.
The cec device node can be used right after it was created, but that
leaves a race condition where the device was created, but devnode->registered
was still false. So an ioctl() would result in an error.

So set it to true before calling cdev_device_add() and to false again if
cdev_device_add returned an error.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
---

Patch

diff --git a/drivers/media/cec/cec-core.c b/drivers/media/cec/cec-core.c
index f5d1578e256a..db7adffcdc76 100644
--- a/drivers/media/cec/cec-core.c
+++ b/drivers/media/cec/cec-core.c
@@ -128,13 +128,14 @@  static int __must_check cec_devnode_register(struct cec_devnode *devnode,
 	devnode->cdev.owner = owner;
 	kobject_set_name(&devnode->cdev.kobj, "cec%d", devnode->minor);

+	devnode->registered = true;
 	ret = cdev_device_add(&devnode->cdev, &devnode->dev);
 	if (ret) {
+		devnode->registered = false;
 		pr_err("%s: cdev_device_add failed\n", __func__);
 		goto clr_bit;
 	}

-	devnode->registered = true;
 	return 0;

 clr_bit:

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