From: Nikolay Aleksandrov <nikolay@xxxxxxxxxx>
[ Upstream commit 8837cbbf854246f5f4d565f21e6baa945d37aded ]
We need a way to release a fib6_nh's per-cpu dsts when replacing
nexthops otherwise we can end up with stale per-cpu dsts which hold net
device references, so add a new IPv6 stub called fib6_nh_release_dsts.
It must be used after an RCU grace period, so no new dsts can be created
through a group's nexthop entry.
Similar to fib6_nh_release it shouldn't be used if fib6_nh_init has failed
so it doesn't need a dummy stub when IPv6 is not enabled.
Fixes: 7bf4796dd099 ("nexthops: add support for replace")
Signed-off-by: Nikolay Aleksandrov <nikolay@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
include/net/ip6_fib.h | 1 +
include/net/ipv6_stubs.h | 1 +
net/ipv6/af_inet6.c | 1 +
net/ipv6/route.c | 19 +++++++++++++++++++
4 files changed, 22 insertions(+)
diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h
index c412dde4d67dc..83b8070d1cc93 100644
--- a/include/net/ip6_fib.h
+++ b/include/net/ip6_fib.h
@@ -485,6 +485,7 @@ int fib6_nh_init(struct net *net, struct fib6_nh *fib6_nh,
struct fib6_config *cfg, gfp_t gfp_flags,
struct netlink_ext_ack *extack);
void fib6_nh_release(struct fib6_nh *fib6_nh);
+void fib6_nh_release_dsts(struct fib6_nh *fib6_nh);
int call_fib6_entry_notifiers(struct net *net,
enum fib_event_type event_type,
diff --git a/include/net/ipv6_stubs.h b/include/net/ipv6_stubs.h
index afbce90c44808..45e0339be6fa4 100644
--- a/include/net/ipv6_stubs.h
+++ b/include/net/ipv6_stubs.h
@@ -47,6 +47,7 @@ struct ipv6_stub {
struct fib6_config *cfg, gfp_t gfp_flags,
struct netlink_ext_ack *extack);
void (*fib6_nh_release)(struct fib6_nh *fib6_nh);
+ void (*fib6_nh_release_dsts)(struct fib6_nh *fib6_nh);
void (*fib6_update_sernum)(struct net *net, struct fib6_info *rt);
int (*ip6_del_rt)(struct net *net, struct fib6_info *rt, bool skip_notify);
void (*fib6_rt_update)(struct net *net, struct fib6_info *rt,
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index 0c4da163535ad..dab4a047590b7 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -1026,6 +1026,7 @@ static const struct ipv6_stub ipv6_stub_impl = {
.ip6_mtu_from_fib6 = ip6_mtu_from_fib6,
.fib6_nh_init = fib6_nh_init,
.fib6_nh_release = fib6_nh_release,
+ .fib6_nh_release_dsts = fib6_nh_release_dsts,
.fib6_update_sernum = fib6_update_sernum_stub,
.fib6_rt_update = fib6_rt_update,
.ip6_del_rt = ip6_del_rt,
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 9b9ef09382ab9..79cb5e5a4948b 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -3680,6 +3680,25 @@ void fib6_nh_release(struct fib6_nh *fib6_nh)
fib_nh_common_release(&fib6_nh->nh_common);
}
+void fib6_nh_release_dsts(struct fib6_nh *fib6_nh)
+{
+ int cpu;
+
+ if (!fib6_nh->rt6i_pcpu)
+ return;
+
+ for_each_possible_cpu(cpu) {
+ struct rt6_info *pcpu_rt, **ppcpu_rt;
+
+ ppcpu_rt = per_cpu_ptr(fib6_nh->rt6i_pcpu, cpu);
+ pcpu_rt = xchg(ppcpu_rt, NULL);
+ if (pcpu_rt) {
+ dst_dev_put(&pcpu_rt->dst);
+ dst_release(&pcpu_rt->dst);
+ }
+ }
+}
+
static struct fib6_info *ip6_route_info_create(struct fib6_config *cfg,
gfp_t gfp_flags,
struct netlink_ext_ack *extack)
--
2.33.0
