diff options
| author | Pavel Emelyanov <xemul@openvz.org> | 2008-02-23 19:57:02 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2008-02-23 19:57:02 -0800 |
| commit | bc4bf5f38cf0a623e6a29f52ec80bfcc56a373c6 (patch) | |
| tree | 44c9dab22f5d75d797845b54df07bd6da40bcc7e /net/core/neighbour.c | |
| parent | 1840bb13c22f5b8fd2e242e36c8d6ea3f312be67 (diff) | |
[NEIGH]: Fix race between neighbor lookup and table's hash_rnd update.
The neigh_hash_grow() may update the tbl->hash_rnd value, which
is used in all tbl->hash callbacks to calculate the hashval.
Two lookup routines may race with this, since they call the
->hash callback without the tbl->lock held. Since the hash_rnd
is changed with this lock write-locked moving the calls to ->hash
under this lock read-locked closes this gap.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/neighbour.c')
| -rw-r--r-- | net/core/neighbour.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/net/core/neighbour.c b/net/core/neighbour.c index 4062b88bfc1b..2328acbd16cd 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -358,11 +358,12 @@ struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey, { struct neighbour *n; int key_len = tbl->key_len; - u32 hash_val = tbl->hash(pkey, dev); + u32 hash_val; NEIGH_CACHE_STAT_INC(tbl, lookups); read_lock_bh(&tbl->lock); + hash_val = tbl->hash(pkey, dev); for (n = tbl->hash_buckets[hash_val & tbl->hash_mask]; n; n = n->next) { if (dev == n->dev && !memcmp(n->primary_key, pkey, key_len)) { neigh_hold(n); @@ -379,11 +380,12 @@ struct neighbour *neigh_lookup_nodev(struct neigh_table *tbl, struct net *net, { struct neighbour *n; int key_len = tbl->key_len; - u32 hash_val = tbl->hash(pkey, NULL); + u32 hash_val; NEIGH_CACHE_STAT_INC(tbl, lookups); read_lock_bh(&tbl->lock); + hash_val = tbl->hash(pkey, NULL); for (n = tbl->hash_buckets[hash_val & tbl->hash_mask]; n; n = n->next) { if (!memcmp(n->primary_key, pkey, key_len) && (net == n->dev->nd_net)) { |