drm/amd/display: Add NULL check for function pointer in dcn32_set_output_transfer_func

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Add NULL check for function pointer in dcn32_set_output_transfer_func This commit adds a null check for the set_output_gamma function pointer in the dcn32_set_output_transfer_func function. Previously, set_output_gamma was being checked for null, but then it was being dereferenced without any null check. This could lead to a null pointer dereference if set_output_gamma is null. To fix this, we now ensure that set_output_gamma is not null before dereferencing it. We do this by adding a null check for set_output_gamma before the call to set_output_gamma.

References

• https://git.kernel.org/stable/c/e087c9738ee1cdeebde346f4dfc819e5f7057e90
• https://git.kernel.org/stable/c/f38b09ba6a335c511eb27920bb9bb4a1b2c20084
• https://git.kernel.org/stable/c/496486950c3d2aebf46a3be300296ac091da7a2d
• https://git.kernel.org/stable/c/5298270bdabe97be5b8236e544c9e936415fe1f2
• https://git.kernel.org/stable/c/28574b08c70e56d34d6f6379326a860b96749051