I see. In light of this commit, is it a better solution than adding NULL-checks
is to replace the if branch conditioned by `WARN_ON` with simply `WARN` like the
following,
struct i2c_adapter *intel_gmbus_get_adapter(struct drm_i915_private *dev_priv,
unsigned int pin)
{
WARN(!intel_gmbus_is_valid_pin(dev_priv, pin), "Invalid pin: %d\n", pin);
return &dev_priv->gmbus[pin].adapter;
}
Shaobo
On 3/18/19 5:53 PM, Rodrigo Vivi wrote:
On Mon, Mar 18, 2019 at 05:39:48PM -0600, Shaobo He wrote:
Hi Rodrigo,
Sorry I'm a bit lost here. May I ask where the `WARN` is?
along with the return NULL
struct i2c_adapter *intel_gmbus_get_adapte()
if (WARN_ON(!intel_gmbus_is_valid_pin(dev_priv, pin)))
return NULL;
Thanks,
Shaobo
On 3/18/19 5:26 PM, Rodrigo Vivi wrote:
Hi Shaobo,
n Mon, Mar 18, 2019 at 05:01:10PM -0600, Shaobo He wrote:
Hello everyone,
My name is Shaobo He and I am a graduate student at University of Utah. I am
using a static analysis tool to search for null pointer dereferences and
came across a potentially invalid memory access in the file
drivers/gpu/drm/i915/intel_crt.c: in function `intel_crt_detect_ddc`,
function `intel_gmbus_get_adapter` can return a NULL pointer which is
if this happens we've done a terrible job on defining the platform...
dereferenced by the call to `drm_get_edid` or `intel_gmbus_is_forced_bit`.
but it seems you are right... this will reach i2c_transfer in the end
and it will break everything after we gave the Warning...
It seems that the return value of `intel_gmbus_get_adapter` is never
NULL-checked. If so, it would be better to replace the branch to return a
NULL pointer with something like `BUG_ON`.
what about just adding if (!i2c) return false
instead of BUG.
We already have the WARN to debug if this case ever happens.
Thanks,
Rodrigo.
Please let me know if it makes sense. I am looking forward to your reply.
Best,
Shaobo
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