On Fri, Feb 16, 2018 at 2:11 PM, Alexey Khoroshilov
<khoroshi...@ispras.ru> wrote:
> There is a single error path where tfile->napi_mutex is left unlocked.
> It can lead to a deadlock.
>
> Found by Linux Driver Verification project (linuxtesting.org).
>
> Signed-off-by: Alexey Khoroshilov <khoroshi...@ispras.ru>
> ---
> drivers/net/tun.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/drivers/net/tun.c b/drivers/net/tun.c
> index 81e6cc951e7f..0072a9832532 100644
> --- a/drivers/net/tun.c
> +++ b/drivers/net/tun.c
> @@ -1879,6 +1879,10 @@ static ssize_t tun_get_user(struct tun_struct *tun,
> struct tun_file *tfile,
> default:
> this_cpu_inc(tun->pcpu_stats->rx_dropped);
> kfree_skb(skb);
> + if (frags) {
> + tfile->napi.skb = NULL;
> + mutex_unlock(&tfile->napi_mutex);
> + }
> return -EINVAL;
I do not believe this can happen for IFF_TUN
IFF_NAPI_FRAGS can only be set for IFF_TAP
