diff options
author | Pavel Emelyanov <xemul@openvz.org> | 2008-06-28 07:06:08 +0400 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2008-06-28 07:06:08 +0400 |
commit | 9a375803feaadb6c34e0807bd9325885dcca5c00 (patch) | |
tree | fba3b0835d1fb3211da1c1be9dd6d4508e6668a6 /net/ipv4/inet_fragment.c | |
parent | a0a61a604c60c14accc3962ecfeee9acc7a3c08a (diff) | |
download | linux-9a375803feaadb6c34e0807bd9325885dcca5c00.tar.xz |
inet fragments: fix race between inet_frag_find and inet_frag_secret_rebuild
The problem is that while we work w/o the inet_frags.lock even
read-locked the secret rebuild timer may occur (on another CPU, since
BHs are still disabled in the inet_frag_find) and change the rnd seed
for ipv4/6 fragments.
It was caused by my patch fd9e63544cac30a34c951f0ec958038f0529e244
([INET]: Omit double hash calculations in xxx_frag_intern) late
in the 2.6.24 kernel, so this should probably be queued to -stable.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/inet_fragment.c')
-rw-r--r-- | net/ipv4/inet_fragment.c | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/net/ipv4/inet_fragment.c b/net/ipv4/inet_fragment.c index 4ed429bd5951..0546a0bc97ea 100644 --- a/net/ipv4/inet_fragment.c +++ b/net/ipv4/inet_fragment.c @@ -192,14 +192,21 @@ EXPORT_SYMBOL(inet_frag_evictor); static struct inet_frag_queue *inet_frag_intern(struct netns_frags *nf, struct inet_frag_queue *qp_in, struct inet_frags *f, - unsigned int hash, void *arg) + void *arg) { struct inet_frag_queue *qp; #ifdef CONFIG_SMP struct hlist_node *n; #endif + unsigned int hash; write_lock(&f->lock); + /* + * While we stayed w/o the lock other CPU could update + * the rnd seed, so we need to re-calculate the hash + * chain. Fortunatelly the qp_in can be used to get one. + */ + hash = f->hashfn(qp_in); #ifdef CONFIG_SMP /* With SMP race we have to recheck hash table, because * such entry could be created on other cpu, while we @@ -247,7 +254,7 @@ static struct inet_frag_queue *inet_frag_alloc(struct netns_frags *nf, } static struct inet_frag_queue *inet_frag_create(struct netns_frags *nf, - struct inet_frags *f, void *arg, unsigned int hash) + struct inet_frags *f, void *arg) { struct inet_frag_queue *q; @@ -255,7 +262,7 @@ static struct inet_frag_queue *inet_frag_create(struct netns_frags *nf, if (q == NULL) return NULL; - return inet_frag_intern(nf, q, f, hash, arg); + return inet_frag_intern(nf, q, f, arg); } struct inet_frag_queue *inet_frag_find(struct netns_frags *nf, @@ -264,7 +271,6 @@ struct inet_frag_queue *inet_frag_find(struct netns_frags *nf, struct inet_frag_queue *q; struct hlist_node *n; - read_lock(&f->lock); hlist_for_each_entry(q, n, &f->hash[hash], list) { if (q->net == nf && f->match(q, key)) { atomic_inc(&q->refcnt); @@ -274,6 +280,6 @@ struct inet_frag_queue *inet_frag_find(struct netns_frags *nf, } read_unlock(&f->lock); - return inet_frag_create(nf, f, key, hash); + return inet_frag_create(nf, f, key); } EXPORT_SYMBOL(inet_frag_find); |