diff options
| author | YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> | 2006-04-28 15:59:15 -0700 |
|---|---|---|
| committer | David S. Miller <davem@sunset.davemloft.net> | 2006-04-29 18:33:22 -0700 |
| commit | c302e6d54e468ee9b1e18152e2e9da06953f3473 (patch) | |
| tree | 23ea6976bef7aad9a934b56714786a0d55256ec6 | |
| parent | e959d8121fcbfee6ec049cc617e9423d1799f2e4 (diff) | |
[IPV6]: Fix race in route selection.
We eliminated rt6_dflt_lock (to protect default router pointer)
at 2.6.17-rc1, and introduced rt6_select() for general router selection.
The function is called in the context of rt6_lock read-lock held,
but this means, we have some race conditions when we do round-robin.
Signed-off-by; YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/ipv6/route.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 79078747a64..0190e39096b 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -317,7 +317,7 @@ static struct rt6_info *rt6_select(struct rt6_info **head, int oif, __FUNCTION__, head, head ? *head : NULL, oif); for (rt = rt0, metric = rt0->rt6i_metric; - rt && rt->rt6i_metric == metric; + rt && rt->rt6i_metric == metric && (!last || rt != rt0); rt = rt->u.next) { int m; @@ -343,9 +343,12 @@ static struct rt6_info *rt6_select(struct rt6_info **head, int oif, (strict & RT6_SELECT_F_REACHABLE) && last && last != rt0) { /* no entries matched; do round-robin */ + static spinlock_t lock = SPIN_LOCK_UNLOCKED; + spin_lock(&lock); *head = rt0->u.next; rt0->u.next = last->u.next; last->u.next = rt0; + spin_unlock(&lock); } RT6_TRACE("%s() => %p, score=%d\n", |