drm/amd/display: Add NULL check for function pointer in dcn401_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 dcn401_set_output_transfer_func This commit adds a null check for the set_output_gamma function pointer in the dcn401_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/d8ee900b92b6526cf84275b49a473155ad75c70e
• https://git.kernel.org/stable/c/dd340acd42c24a3f28dd22fae6bf38662334264c