From: Jason Wang jasowang@redhat.com
[ Upstream commit a35d310f03a692bf4798eb309a1950a06a150620 ]
We need check if tun->numqueues is zero (e.g for the persist device) before trying to use it for modular arithmetic.
Reported-by: Eric Dumazet eric.dumazet@gmail.com Fixes: 96f84061620c6("tun: add eBPF based queue selection method") Signed-off-by: Jason Wang jasowang@redhat.com Reviewed-by: Eric Dumazet edumazet@google.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/tun.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
--- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -596,13 +596,18 @@ static u16 tun_automq_select_queue(struc static u16 tun_ebpf_select_queue(struct tun_struct *tun, struct sk_buff *skb) { struct tun_prog *prog; + u32 numqueues; u16 ret = 0;
+ numqueues = READ_ONCE(tun->numqueues); + if (!numqueues) + return 0; + prog = rcu_dereference(tun->steering_prog); if (prog) ret = bpf_prog_run_clear_cb(prog->prog, skb);
- return ret % tun->numqueues; + return ret % numqueues; }
static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,