2024-03-14 12:57:15

by Marek Szyprowski

Subject: [PATCH] cpufreq: dt: always allocate zeroed cpumask

Commit 0499a78369ad ("ARM64: Dynamically allocate cpumasks and increase
supported CPUs to 512") changed the handling of cpumasks on ARM 64bit,
what resulted in the strange issues and warnings during cpufreq-dt
initialization on some big.LITTLE platforms.

This was caused by mixing OPPs between big and LITTLE cores, because
OPP-sharing information between big and LITTLE cores is computed on
cpumask, which in turn was not zeroed on allocation. Fix this by
switching to zalloc_cpumask_var() call.

Fixes: dc279ac6e5b4 ("cpufreq: dt: Refactor initialization to handle probe deferral properly")
CC: [email protected] # v5.10+
Signed-off-by: Marek Szyprowski <[email protected]>
---
drivers/cpufreq/cpufreq-dt.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/cpufreq/cpufreq-dt.c b/drivers/cpufreq/cpufreq-dt.c
index 8bd6e5e8f121..2d83bbc65dd0 100644
--- a/drivers/cpufreq/cpufreq-dt.c
+++ b/drivers/cpufreq/cpufreq-dt.c
@@ -208,7 +208,7 @@ static int dt_cpufreq_early_init(struct device *dev, int cpu)
if (!priv)
return -ENOMEM;

- if (!alloc_cpumask_var(&priv->cpus, GFP_KERNEL))
+ if (!zalloc_cpumask_var(&priv->cpus, GFP_KERNEL))
return -ENOMEM;

cpumask_set_cpu(cpu, priv->cpus);
--
2.34.1

2024-03-14 17:19:09

by Christoph Lameter (Ampere)

Subject: Re: [PATCH] cpufreq: dt: always allocate zeroed cpumask

On Thu, 14 Mar 2024, Marek Szyprowski wrote:

> - if (!alloc_cpumask_var(&priv->cpus, GFP_KERNEL))
> + if (!zalloc_cpumask_var(&priv->cpus, GFP_KERNEL))
> return -ENOMEM;

Reviewed-by: Christoph Lameter (Ampere) <[email protected]>

2024-03-15 05:29:05

by Dhruva Gole

Subject: Re: [PATCH] cpufreq: dt: always allocate zeroed cpumask

On Mar 14, 2024 at 13:54:57 +0100, Marek Szyprowski wrote:
> Commit 0499a78369ad ("ARM64: Dynamically allocate cpumasks and increase
> supported CPUs to 512") changed the handling of cpumasks on ARM 64bit,
> what resulted in the strange issues and warnings during cpufreq-dt
> initialization on some big.LITTLE platforms.
>
> This was caused by mixing OPPs between big and LITTLE cores, because
> OPP-sharing information between big and LITTLE cores is computed on
> cpumask, which in turn was not zeroed on allocation. Fix this by
> switching to zalloc_cpumask_var() call.
>
> Fixes: dc279ac6e5b4 ("cpufreq: dt: Refactor initialization to handle probe deferral properly")
> CC: [email protected] # v5.10+
> Signed-off-by: Marek Szyprowski <[email protected]>
> ---
> drivers/cpufreq/cpufreq-dt.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/cpufreq/cpufreq-dt.c b/drivers/cpufreq/cpufreq-dt.c
> index 8bd6e5e8f121..2d83bbc65dd0 100644
> --- a/drivers/cpufreq/cpufreq-dt.c
> +++ b/drivers/cpufreq/cpufreq-dt.c
> @@ -208,7 +208,7 @@ static int dt_cpufreq_early_init(struct device *dev, int cpu)
> if (!priv)
> return -ENOMEM;
>
> - if (!alloc_cpumask_var(&priv->cpus, GFP_KERNEL))
> + if (!zalloc_cpumask_var(&priv->cpus, GFP_KERNEL))
> return -ENOMEM;

Good catch!

Reviewed-by: Dhruva Gole <[email protected]>


--
Best regards,
Dhruva

2024-03-15 05:50:47

by Viresh Kumar

Subject: Re: [PATCH] cpufreq: dt: always allocate zeroed cpumask

On 14-03-24, 13:54, Marek Szyprowski wrote:
> Commit 0499a78369ad ("ARM64: Dynamically allocate cpumasks and increase
> supported CPUs to 512") changed the handling of cpumasks on ARM 64bit,
> what resulted in the strange issues and warnings during cpufreq-dt
> initialization on some big.LITTLE platforms.
>
> This was caused by mixing OPPs between big and LITTLE cores, because
> OPP-sharing information between big and LITTLE cores is computed on
> cpumask, which in turn was not zeroed on allocation. Fix this by
> switching to zalloc_cpumask_var() call.
>
> Fixes: dc279ac6e5b4 ("cpufreq: dt: Refactor initialization to handle probe deferral properly")
> CC: [email protected] # v5.10+
> Signed-off-by: Marek Szyprowski <[email protected]>
> ---
> drivers/cpufreq/cpufreq-dt.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/cpufreq/cpufreq-dt.c b/drivers/cpufreq/cpufreq-dt.c
> index 8bd6e5e8f121..2d83bbc65dd0 100644
> --- a/drivers/cpufreq/cpufreq-dt.c
> +++ b/drivers/cpufreq/cpufreq-dt.c
> @@ -208,7 +208,7 @@ static int dt_cpufreq_early_init(struct device *dev, int cpu)
> if (!priv)
> return -ENOMEM;
>
> - if (!alloc_cpumask_var(&priv->cpus, GFP_KERNEL))
> + if (!zalloc_cpumask_var(&priv->cpus, GFP_KERNEL))
> return -ENOMEM;
>
> cpumask_set_cpu(cpu, priv->cpus);

Applied. Thanks.

--
viresh