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Subject: Re: [PATCH] iio: buffer: use sysfs_attr_init() on allocated attrs
To:     Alexandru Ardelean <aardelean@deviqon.com>,
        linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org
Cc:     jic23@kernel.org
From:   Marek Szyprowski <m.szyprowski@samsung.com>
Message-ID: <6c77abb2-0b6f-a745-0950-0be34d41913e@samsung.com>
Date:   Tue, 6 Apr 2021 08:17:09 +0200
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On 02.04.2021 19:42, Alexandru Ardelean wrote:
> When dynamically allocating sysfs attributes, it's a good idea to call
> sysfs_attr_init() on them to initialize lock_class_keys.
> This change does that.
>
> The lock_class_keys are set when the CONFIG_DEBUG_LOCK_ALLOC symbol is
> enabled. Which is [likely] one reason why I did not see this during
> development.
>
> I also am not able to see this even with CONFIG_DEBUG_LOCK_ALLOC enabled,
> so this may [likely] be reproduce-able on some system configurations.
>
> This was reported via:
>    https://lore.kernel.org/linux-iio/CA+U=DsrsvGgXEF30-vXuXS_k=-mjSjiBwEEzwKb1hJVn1P98OA@mail.gmail.com/T/#u
>
> Fixes: 15097c7a1adc ("iio: buffer: wrap all buffer attributes into iio_dev_attr")
> Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Signed-off-by: Alexandru Ardelean <aardelean@deviqon.com>
> ---
>
> @Marek: could you maybe test this on your setup?
>
> I haven't been able to reproduce this on mine.

Works fine with this fix. Thanks!

Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>

> Thanks
> Alex
>
>   drivers/iio/industrialio-buffer.c | 1 +
>   1 file changed, 1 insertion(+)
>
> diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
> index ee5aab9d4a23..06b2ea087408 100644
> --- a/drivers/iio/industrialio-buffer.c
> +++ b/drivers/iio/industrialio-buffer.c
> @@ -1309,6 +1309,7 @@ static struct attribute *iio_buffer_wrap_attr(struct iio_buffer *buffer,
>   	iio_attr->buffer = buffer;
>   	memcpy(&iio_attr->dev_attr, dattr, sizeof(iio_attr->dev_attr));
>   	iio_attr->dev_attr.attr.name = kstrdup_const(attr->name, GFP_KERNEL);
> +	sysfs_attr_init(&iio_attr->dev_attr.attr);
>   
>   	list_add(&iio_attr->l, &buffer->buffer_attr_list);
>   

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland