In the Linux kernel, the following vulnerability has been resolved:
bus: fsl-mc: fix double-free on mc_dev
The blamed commit tried to simplify how the deallocations are done but, in the process, introduced a double-free on the mc_dev variable.
In case the MC device is a DPRC, a new mcbus is allocated and the mcdev variable is just a reference to one of its fields. In this circumstance, on the error path only the mc_bus should be freed.
This commit introduces back the following checkpatch warning which is a false-positive.
WARNING: kfree(NULL) is safe and this check is probably not required + if (mcbus) + kfree(mcbus);