Re: [PATCH] speakup: Add spinlock in synth_direct_store

Samuel Thibault
2016-09-05T22:02:42Z

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@ispras.ru>

Reviewed-by: Samuel Thibault <samuel.thibault@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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