On July 30, 2020 11:48:06 Dan Carpenter <dan.carpenter@xxxxxxxxxx> wrote:
On Wed, Jul 29, 2020 at 06:13:44PM +0300, Andy Shevchenko wrote:
On Wed, Jul 29, 2020 at 5:00 PM Cengiz Can <cengiz@xxxxxxxxxx> wrote:
`find_gmin_subdev` function that returns a pointer to `struct
gmin_subdev` can return NULL.
In `gmin_v2p8_ctrl` there's a call to this function but the possibility
of a NULL was not checked before its being dereferenced. ie:
```
/* Acquired here --------v */
struct gmin_subdev *gs = find_gmin_subdev(subdev);
int ret;
int value;
/* v------Dereferenced here */
if (gs->v2p8_gpio >= 0) {
pr_info("atomisp_gmin_platform: 2.8v power on GPIO %d\n",
gs->v2p8_gpio);
ret = gpio_request(gs->v2p8_gpio, "camera_v2p8");
if (!ret)
ret = gpio_direction_output(gs->v2p8_gpio, 0);
if (ret)
pr_err("V2P8 GPIO initialization failed\n");
}
```
I have moved the NULL check before deref point.
"Move the NULL check..."
See Submitting Patches documentation how to avoid "This patch", "I", "we", etc.
Noted. Sorry. I'm not a native English speaker.
I always feel like this is a pointless requirement. We're turning into
bureaucracts.
diff --git a/drivers/staging/media/atomisp/pci/atomisp_gmin_platform.c
b/drivers/staging/media/atomisp/pci/atomisp_gmin_platform.c
index 0df46a1af5f0..8e9c5016f299 100644
--- a/drivers/staging/media/atomisp/pci/atomisp_gmin_platform.c
+++ b/drivers/staging/media/atomisp/pci/atomisp_gmin_platform.c
@@ -871,6 +871,11 @@ static int gmin_v2p8_ctrl(struct v4l2_subdev *subdev,
int on)
int ret;
int value;
+ if (!gs) {
+ pr_err("Unable to find gmin subdevice\n");
+ return -EINVAL;
And here is a change of semantics...
Yeah. The change of semantics should be documented in the commit
message, but it's actually correct. I discussed this with Mauro earlier
but my bug reporting script didn't CC a mailing list and I didn't
catch it. Mauro suggested:
53 > Yet, it could make sense to have something like:
54 >
55 > if (WARN_ON(!gs))
56 > return -ENODEV;
57 >
58 > at the beginning of the functions that call find_gmin_subdev().
I will be updating v2 according to this.
regards,
dan carpenter
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