On Thu, Apr 01, 2021 at 06:11:27PM +0200, Maciej Falkowski wrote:
> The current control flow of IRQ number assignment to `irq` variable
> allows a request of IRQ of unspecified value,
> generating a warning under Clang compilation with omap1_defconfig on linux-next:
>
> arch/arm/mach-omap1/pm.c:656:11: warning: variable 'irq' is used uninitialized whenever
> 'if' condition is false [-Wsometimes-uninitialized]
> else if (cpu_is_omap16xx())
> ^~~~~~~~~~~~~~~~~
> ./arch/arm/mach-omap1/include/mach/soc.h:123:30: note: expanded from macro 'cpu_is_omap16xx'
> ^~~~~~~~~~~~~
> arch/arm/mach-omap1/pm.c:658:18: note: uninitialized use occurs here
> if (request_irq(irq, omap_wakeup_interrupt, 0, "peripheral wakeup",
> ^~~
> arch/arm/mach-omap1/pm.c:656:7: note: remove the 'if' if its condition is always true
> else if (cpu_is_omap16xx())
> ^~~~~~~~~~~~~~~~~~~~~~
> arch/arm/mach-omap1/pm.c:611:9: note: initialize the variable 'irq' to silence this warning
> int irq;
> ^
> = 0
> 1 warning generated.
>
> The patch provides a default value to the `irq` variable
> along with a validity check.
>
Might be worth a fixes tag:
Fixes: b75ca5217743 ("ARM: OMAP: replace setup_irq() by request_irq()")
> Signed-off-by: Maciej Falkowski <[email protected]>
> Link: https://github.com/ClangBuiltLinux/linux/issues/1324
Reviewed-by: Nathan Chancellor <[email protected]>
> ---
> arch/arm/mach-omap1/pm.c | 10 +++++++---
> 1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/arch/arm/mach-omap1/pm.c b/arch/arm/mach-omap1/pm.c
> index 2c1e2b32b9b3..a745d64d4699 100644
> --- a/arch/arm/mach-omap1/pm.c
> +++ b/arch/arm/mach-omap1/pm.c
> @@ -655,9 +655,13 @@ static int __init omap_pm_init(void)
> irq = INT_7XX_WAKE_UP_REQ;
> else if (cpu_is_omap16xx())
> irq = INT_1610_WAKE_UP_REQ;
> - if (request_irq(irq, omap_wakeup_interrupt, 0, "peripheral wakeup",
> - NULL))
> - pr_err("Failed to request irq %d (peripheral wakeup)\n", irq);
> + else
> + irq = -1;
> +
> + if (irq >= 0) {
> + if (request_irq(irq, omap_wakeup_interrupt, 0, "peripheral wakeup", NULL))
> + pr_err("Failed to request irq %d (peripheral wakeup)\n", irq);
> + }
>
> /* Program new power ramp-up time
> * (0 for most boards since we don't lower voltage when in deep sleep)
> --
> 2.26.3
>