[PATCH 4.9 082/102] clk: sunxi: fix uninitialized access

Greg Kroah-Hartman
2019-07-08T15:22:24Z

From: Arnd Bergmann <arnd@arndb.de>

commit 4e903450bcb9a6bc90733b981d7cb8b3c4996a0e upstream.

gcc-8 reports an uninitialized variable access in a code path
that we would see with incorrect DTB input:

drivers/clk/sunxi/clk-sun8i-bus-gates.c: In function 'sun8i_h3_bus_gates_init':
drivers/clk/sunxi/clk-sun8i-bus-gates.c:85:27: error: 'clk_parent' may be used uninitialized in this function [-Werror=maybe-uninitialized]

This works around by skipping invalid input and printing a warning
instead if it ever happens. The problem was apparently part of the
initiali driver submission, but older compilers don't notice it.

Fixes: ab6e23a4e388 ("clk: sunxi: Add H3 clocks support")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/clk/sunxi/clk-sun8i-bus-gates.c | 4 ++++
1 file changed, 4 insertions(+)

--- a/drivers/clk/sunxi/clk-sun8i-bus-gates.c
+++ b/drivers/clk/sunxi/clk-sun8i-bus-gates.c
@@ -78,6 +78,10 @@ static void __init sun8i_h3_bus_gates_in
clk_parent = APB1;
else if (index >= 96 && index <= 127)
clk_parent = APB2;
+ else {
+ WARN_ON(true);
+ continue;
+ }

clk_reg = reg + 4 * (index / 32);
clk_bit = index % 32;