diff options
| -rw-r--r-- | net/ipv6/ip6_fib.c | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c index dd26657b6a4a..45ef4d65dcbc 100644 --- a/net/ipv6/ip6_fib.c +++ b/net/ipv6/ip6_fib.c @@ -727,20 +727,28 @@ unlock: void fib6_metric_set(struct fib6_info *f6i, int metric, u32 val) { + struct dst_metrics *m; + if (!f6i) return; - if (f6i->fib6_metrics == &dst_default_metrics) { + if (READ_ONCE(f6i->fib6_metrics) == &dst_default_metrics) { + struct dst_metrics *dflt = (struct dst_metrics *)&dst_default_metrics; struct dst_metrics *p = kzalloc_obj(*p, GFP_ATOMIC); if (!p) return; + p->metrics[metric - 1] = val; refcount_set(&p->refcnt, 1); - f6i->fib6_metrics = p; + if (cmpxchg(&f6i->fib6_metrics, dflt, p) != dflt) + kfree(p); + else + return; } - f6i->fib6_metrics->metrics[metric - 1] = val; + m = READ_ONCE(f6i->fib6_metrics); + WRITE_ONCE(m->metrics[metric - 1], val); } /* |