kernel: lib/generic-radix-tree.c: Fix rare race in __genradix_ptr_alloc()

In the Linux kernel, the following vulnerability has been resolved: lib/generic-radix-tree.c: Fix rare race in genradixptralloc If we need to increase the tree depth, allocate a new node, and then race with another thread that increased the tree depth before us, we'll still have a preallocated no...