[PATCH] speakup: Add spinlock in synth_direct_store

[Samuel Thibault]

Pavel Andrianov, on Mon 05 Sep 2016 16:17:47 +0300, wrote:
> All operations with synth buffer should be protected,
> as there are global pointers, which should be modified atomically.
> 
> Found by Linux Driver Verification project (linuxtesting.org)
> 
> Signed-off-by: Pavel Andrianov <andrianov at ispras.ru>

Reviewed-by: Samuel Thibault <samuel.thibault at ens-lyon.org>

> ---
>  drivers/staging/speakup/kobjects.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/staging/speakup/kobjects.c b/drivers/staging/speakup/kobjects.c
> index 528cbdc..7fedee3 100644
> --- a/drivers/staging/speakup/kobjects.c
> +++ b/drivers/staging/speakup/kobjects.c
> @@ -411,11 +411,13 @@ static ssize_t synth_direct_store(struct kobject *kobj,
>  	int len;
>  	int bytes;
>  	const char *ptr = buf;
> +	unsigned long flags;
>  
>  	if (!synth)
>  		return -EPERM;
>  
>  	len = strlen(buf);
> +	spin_lock_irqsave(&speakup_info.spinlock, flags);
>  	while (len > 0) {
>  		bytes = min_t(size_t, len, 250);
>  		strncpy(tmp, ptr, bytes);
> @@ -425,6 +427,7 @@ static ssize_t synth_direct_store(struct kobject *kobj,
>  		ptr += bytes;
>  		len -= bytes;
>  	}
> +	spin_unlock_irqrestore(&speakup_info.spinlock, flags);
>  	return count;
>  }
>  
> -- 
> 2.7.4
> 

-- 
Samuel
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