clk: samsung: exynos-clkout: Assign .num before accessing .hws

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: clk: samsung: exynos-clkout: 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 (UBSAN_BOUNDS) 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 exynos_clkout_probe() due to .num being assigned after .hws[] has been accessed: UBSAN: array-index-out-of-bounds in drivers/clk/samsung/clk-exynos-clkout.c:178:18 index 0 is out of range for type 'clk_hw *[*]' Move the .num initialization to before the first access of .hws[], clearing up the warning.

References

• https://git.kernel.org/stable/c/fbf57f5e453dadadb3d29b2d1dbe067e3dc4e236
• https://git.kernel.org/stable/c/eb1f3a6ab3efee2b52361879cdc2dc6b11f499c0
• https://git.kernel.org/stable/c/a317f63255ebc3dac378c79c5bff4f8d0561c290
• https://git.kernel.org/stable/c/cf33f0b7df13685234ccea7be7bfe316b60db4db