Re: [PATCH] ARM: STi: at least warn if of_iomap fails
From: Patrice CHOTARD
Date: Mon Jul 16 2018 - 03:55:43 EST
Hi Nicholas
On 07/12/2018 05:48 PM, Nicholas Mc Guire wrote:
> The call to of_iomap() is unchecked but scu_enable(), which the returned
> address is passed on to, assumes a valid mapping. If the mapping is
> invalid this could probably lead to undefined system state so at least
> a warning should be issued.
>
> Signed-off-by: Nicholas Mc Guire <hofrat@xxxxxxxxx>
> Fixes: commit 65ebcc115889 ("ARM: sti: Add STiH415 SOC support")
> ---
> Problem was found by an experimental coccinelle script
>
> Patch was compile tested with: multi_v7_defconfig (implies
> CONFIG_ARCH_STI=y, CONFIG_SMP=y)
>
> Patch is against 4.18-rc3 (localversion-next is next-20180712)
>
> arch/arm/mach-sti/platsmp.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/arm/mach-sti/platsmp.c b/arch/arm/mach-sti/platsmp.c
> index 231f19e..89ae76f 100644
> --- a/arch/arm/mach-sti/platsmp.c
> +++ b/arch/arm/mach-sti/platsmp.c
> @@ -109,6 +109,7 @@ static void __init sti_smp_prepare_cpus(unsigned int max_cpus)
>
> if (np) {
> scu_base = of_iomap(np, 0);
> + WARN_ON(!scu_base);
> scu_enable(scu_base);
> of_node_put(np);
> }
>
I should prefer to exit with an error to avoid unpredictable behavior,
something like this is better :
scu_base = of_iomap(np, 0);
of_node_put(np);
if (!scu_base) {
pr_err("No SCU remap\n");
return;
}
scu_enable(scu_base);
Thanks