4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx> [ Upstream commit 178fe94405bffbd1acd83b6ff3b40211185ae9c9 ] 'ipv6_find_idev()' returns NULL on error, not an error pointer. Update the test accordingly and return -ENOBUFS, as already done in 'addrconf_add_dev()', if NULL is returned. Fixes: ("ipv6: allow userspace to add IFA_F_OPTIMISTIC addresses") Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/ipv6/addrconf.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -4711,8 +4711,8 @@ inet6_rtm_newaddr(struct sk_buff *skb, s IFA_F_MCAUTOJOIN | IFA_F_OPTIMISTIC; idev = ipv6_find_idev(dev); - if (IS_ERR(idev)) - return PTR_ERR(idev); + if (!idev) + return -ENOBUFS; if (!ipv6_allow_optimistic_dad(net, idev)) cfg.ifa_flags &= ~IFA_F_OPTIMISTIC;