From: YueHaibing <yuehaibing@xxxxxxxxxx> [ Upstream commit fa89a4593b927b3f59c3b69379f31d3b22272e4e ] gcc warn this: net/ipv6/xfrm6_tunnel.c:143 __xfrm6_tunnel_alloc_spi() warn: always true condition '(spi <= 4294967295) => (0-u32max <= u32max)' 'spi' is u32, which always not greater than XFRM6_TUNNEL_SPI_MAX because of wrap around. So the second forloop will never reach. Signed-off-by: YueHaibing <yuehaibing@xxxxxxxxxx> Signed-off-by: Steffen Klassert <steffen.klassert@xxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- net/ipv6/xfrm6_tunnel.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/ipv6/xfrm6_tunnel.c b/net/ipv6/xfrm6_tunnel.c index 4e438bc7ee87..c28e3eaad7c2 100644 --- a/net/ipv6/xfrm6_tunnel.c +++ b/net/ipv6/xfrm6_tunnel.c @@ -144,6 +144,9 @@ static u32 __xfrm6_tunnel_alloc_spi(struct net *net, xfrm_address_t *saddr) index = __xfrm6_tunnel_spi_check(net, spi); if (index >= 0) goto alloc_spi; + + if (spi == XFRM6_TUNNEL_SPI_MAX) + break; } for (spi = XFRM6_TUNNEL_SPI_MIN; spi < xfrm6_tn->spi; spi++) { index = __xfrm6_tunnel_spi_check(net, spi); -- 2.19.1