clk: bcm: rpi: Assign ->num before accessing ->hws

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: clk: bcm: rpi: Assign ->num before accessing ->hws Commit f316cdff8d67 ("clk: Annotate struct clk_hw_onecell_data with __counted_by") annotated the hws member of 'struct clk_hw_onecell_data' with __counted_by, which informs the bounds sanitizer about the number of elements in hws, so that it can warn when hws is accessed out of bounds. As noted in that change, the __counted_by member must be initialized with the number of elements before the first array access happens, otherwise there will be a warning from each access prior to the initialization because the number of elements is zero. This occurs in raspberrypi_discover_clocks() due to ->num being assigned after ->hws has been accessed: UBSAN: array-index-out-of-bounds in drivers/clk/bcm/clk-raspberrypi.c:374:4 index 3 is out of range for type 'struct clk_hw *[] __counted_by(num)' (aka 'struct clk_hw *[]') Move the ->num initialization to before the first access of ->hws, which clears up the warning.

References

• https://git.kernel.org/stable/c/9562dbe5cdbb16ac887d27ef6f179980bb99193c
• https://git.kernel.org/stable/c/cdf9c7871d58d3df59d2775982e3533adb8ec920
• https://git.kernel.org/stable/c/6dc445c1905096b2ed4db1a84570375b4e00cc0f