From: Ambresh K <ambresh@xxxxxx> On a possible HW bug or in-correct configuration of MUX register's in bootloader; might return a value greater than available parent clocks for a MUX clk. Sensing invalid parent index, clk_mux_get_parent returns -EINVALID. Due to function's "u8" return type it will get converted into signed value, thus causing following pointer dereference on test platform. M[ 0.000000] dra7xx_clk_init: clk init (gpu_core_gclk_mux)^M ^M[ 0.000000] Unable to handle kernel NULL pointer dereference at virtual address 00000000^M ^M[ 0.000000] pgd = c0004000^M ^M[ 0.000000] [00000000] *pgd=00000000^M ^M[ 0.000000] Internal error: Oops: 5 [#1] SMP ARM^M ^M[ 0.000000] Modules linked in:^M ^M[ 0.000000] CPU: 0 Not tainted (3.8.4-gb746a7c-dirty #59)^M ^M[ 0.000000] PC is at strcmp+0x8/0x34^M Changes since v1: - Fixed review comments. - Fixed return type of .get_parent callback function. Ambresh K (3): clk: fix clk_mux_get_parent return's signed value clk: skip re-parenting orphan clk ARM: OMAP2+: clk: Fix return type of callbacks arch/arm/mach-omap2/clkt_clksel.c | 2 +- arch/arm/mach-omap2/clkt_dpll.c | 2 +- arch/arm/mach-omap2/clock.h | 4 ++-- drivers/clk/clk-mux.c | 2 +- drivers/clk/clk.c | 16 +++++++++++++++- include/linux/clk-provider.h | 6 +++--- 6 files changed, 23 insertions(+), 9 deletions(-) -- 1.7.4.1 -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html