diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c index 31d77885bcae3e3843b6d486cfc21cdbe709bcf0..6e57c03e3255f09ac3927fd4b61232ed07103332 100644 --- a/net/ipv6/ip6_fib.c +++ b/net/ipv6/ip6_fib.c @@ -966,6 +966,7 @@ static void __fib6_drop_pcpu_from(struct fib6_nh *fib6_nh, if (!fib6_nh->rt6i_pcpu) return; + rcu_read_lock(); /* release the reference to this fib entry from * all of its cached pcpu routes */ @@ -974,7 +975,9 @@ static void __fib6_drop_pcpu_from(struct fib6_nh *fib6_nh, struct rt6_info *pcpu_rt; ppcpu_rt = per_cpu_ptr(fib6_nh->rt6i_pcpu, cpu); - pcpu_rt = *ppcpu_rt; + + /* Paired with xchg() in rt6_get_pcpu_route() */ + pcpu_rt = READ_ONCE(*ppcpu_rt); /* only dropping the 'from' reference if the cached route * is using 'match'. The cached pcpu_rt->from only changes @@ -988,6 +991,7 @@ static void __fib6_drop_pcpu_from(struct fib6_nh *fib6_nh, fib6_info_release(from); } } + rcu_read_unlock(); } struct fib6_nh_pcpu_arg { diff --git a/net/ipv6/route.c b/net/ipv6/route.c index a504b88ec06b5aec6b0f915c3ff044cd98f864ab..f083d9faba6b1e544121d711c8cf391aea292f37 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -1409,6 +1409,7 @@ static struct rt6_info *rt6_get_pcpu_route(const struct fib6_result *res) struct rt6_info *prev, **p; p = this_cpu_ptr(res->nh->rt6i_pcpu); + /* Paired with READ_ONCE() in __fib6_drop_pcpu_from() */ prev = xchg(p, NULL); if (prev) { dst_dev_put(&prev->dst);