net/ipv6: separate handling of FIB entries from dst based routes

Hello David Ahern,

This is a semi-automatic email about new static checker warnings.

The patch 93531c674315: "net/ipv6: separate handling of FIB entries from dst based routes" from Apr 17, 2018, leads to the following Smatch complaint:

net/ipv6/route.c:2128 fib6_check()
error: we previously assumed 'f6i' could be null (see line 2124)

net/ipv6/route.c
2123 /*
2124 * Destination cache support functions
2125 */
2126
2127 static bool fib6_check(struct fib6_info *f6i, u32 cookie)
2128 {
2129 u32 rt_cookie = 0;
2130
2131 if ((f6i && !rt6_get_cookie_safe(f6i, &rt_cookie)) ||

                     ^^^

Check

2132 rt_cookie != cookie)
2133 return false;
2134
2135 if (fib6_check_expired(f6i))

                                       ^^^

Unchecked dereference inside function.

2136 return false;
2137
2138 return true;
2139 }

regards,
dan carpenter