The commit 2b760fcf5cfb ("ipv6: hook up exception table to store
dst cache") partially reverted 1e2ea8ad37be ("ipv6: set
dst.obsolete when a cached route has expired").
As a result, RTF_CACHE dst referenced outside the fib tree will
not be removed until the next sernum change; dst_check() does not
fail on aged-out dst, and dst->__refcnt can't decrease: the aged
out dst will stay valid for a potentially unlimited time after the
timeout expiration.
This change explicitly removes RTF_CACHE dst from the fib tree when
aged out. The rt6_remove_exception() logic will then obsolete the
dst and other entities will drop the related reference on next
dst_check().
v1 -> v2:
- do not touch dst.obsolete in rt6_remove_exception(), not needed
Fixes: 2b760fcf5cfb ("ipv6: hook up exception table to store dst cache")
Signed-off-by: Paolo Abeni <pab...@redhat.com>
---
net/ipv6/route.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 5c27313803d2..a4a7f199120e 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1575,8 +1575,11 @@ static void rt6_age_examine_exception(struct
rt6_exception_bucket *bucket,
{
struct rt6_info *rt = rt6_ex->rt6i;
- if (atomic_read(&rt->dst.__refcnt) == 1 &&
- time_after_eq(now, rt->dst.lastuse + gc_args->timeout)) {
+ /* we are pruning and obsoleting the exception route even if others
+ * have still reference to it, so that on next dst_check() such
+ * reference can be dropped
+ */
+ if (time_after_eq(now, rt->dst.lastuse + gc_args->timeout)) {
RT6_TRACE("aging clone %p\n", rt);
rt6_remove_exception(bucket, rt6_ex);
return;
--
2.13.6
