@@ -633,18 +633,17 @@ static bool rt6_qualify_for_ecmp(struct rt6_info *rt)
static int fib6_commit_metrics(struct dst_entry *dst,
struct nlattr *mx, int mx_len)
{
+ bool dst_host = dst->flags & DST_HOST;
struct nlattr *nla;
int remaining;
u32 *mp;
- if (dst->flags & DST_HOST) {
- mp = dst_metrics_write_ptr(dst);
- } else {
- mp = kzalloc(sizeof(u32) * RTAX_MAX, GFP_ATOMIC);
- if (!mp)
- return -ENOMEM;
+ mp = dst_host ? dst_metrics_write_ptr(dst) :
+ kzalloc(sizeof(u32) * RTAX_MAX, GFP_ATOMIC);
+ if (unlikely(!mp))
+ return -ENOMEM;
+ if (!dst_host)
dst_init_metrics(dst, mp, 0);
- }
nla_for_each_attr(nla, mx, mx_len, remaining) {
int type = nla_type(nla);
When IPv6 host routes with metrics attached are being added, we fetch the metrics store from the dst via COW through dst_metrics_write_ptr(), added through commit e5fd387ad5b3. One remaining problem here is that we actually call into inet_getpeer() and may end up allocating/creating a new peer from the kmemcache, which may fail. Example trace from perf probe (inet_getpeer:41) where create is 1: ip 6877 [002] 4221.391591: probe:inet_getpeer: (ffffffff8165e293) 85e294 inet_getpeer.part.7 (<- kmem_cache_alloc()) 85e578 inet_getpeer 8eb333 ipv6_cow_metrics 8f10ff fib6_commit_metrics Therefore, a check for NULL on the return of dst_metrics_write_ptr() is necessary here. Joint work with Florian Westphal. Fixes: e5fd387ad5b3 ("ipv6: do not overwrite inetpeer metrics prematurely") Cc: Michal Kubeček <mkubecek@suse.cz> Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Daniel Borkmann <dborkman@redhat.com> --- net/ipv6/ip6_fib.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-)