Le dimanche 02 mai 2010 à 13:46 -0400, Valdis.Kletnieks@xxxxxx a écrit : > On Wed, 28 Apr 2010 16:53:32 PDT, akpm@xxxxxxxxxxxxxxxxxxxx said: > > The mm-of-the-moment snapshot 2010-04-28-16-53 has been uploaded to > > > > http://userweb.kernel.org/~akpm/mmotm/ > > I thought we swatted all these, hit another one... > > [ 9.131490] ctnetlink v0.93: registering with nfnetlink. > [ 9.131535] > [ 9.131535] =================================================== > [ 9.131704] [ INFO: suspicious rcu_dereference_check() usage. ] > [ 9.131794] --------------------------------------------------- > [ 9.131883] net/netfilter/nf_conntrack_ecache.c:88 invoked rcu_dereference_check() without protection! > [ 9.131977] > [ 9.131977] other info that might help us debug this: > [ 9.131978] > [ 9.132218] > [ 9.132219] rcu_scheduler_active = 1, debug_locks = 0 > [ 9.132434] 1 lock held by swapper/1: > [ 9.132519] #0: (nf_ct_ecache_mutex){+.+...}, at: [<ffffffff8148922d>] nf_conntrack_register_notifier+0x1a/0x75 > [ 9.132938] > [ 9.132939] stack backtrace: > [ 9.133129] Pid: 1, comm: swapper Tainted: G W 2.6.34-rc5-mmotm0428 #1 > [ 9.133220] Call Trace: > [ 9.133319] [<ffffffff81064832>] lockdep_rcu_dereference+0xaa/0xb2 > [ 9.133410] [<ffffffff81489250>] nf_conntrack_register_notifier+0x3d/0x75 > [ 9.133521] [<ffffffff81b5a157>] ctnetlink_init+0x71/0xd5 > [ 9.133627] [<ffffffff81b5a0e6>] ? ctnetlink_init+0x0/0xd5 > [ 9.133735] [<ffffffff810001ef>] do_one_initcall+0x59/0x14e > [ 9.133843] [<ffffffff81b2e68a>] kernel_init+0x144/0x1ce > [ 9.133949] [<ffffffff81003414>] kernel_thread_helper+0x4/0x10 > [ 9.134060] [<ffffffff81598a40>] ? restore_args+0x0/0x30 > [ 9.134196] [<ffffffff81b2e546>] ? kernel_init+0x0/0x1ce > [ 9.134328] [<ffffffff81003410>] ? kernel_thread_helper+0x0/0x10 > [ 9.134530] ip_tables: (C) 2000-2006 Netfilter Core Team > [ 9.134655] TCP bic registered > Thanks for the report ! We can use rcu_dereference_protected() in those cases. [PATCH] net: Use rcu_dereference_protected in nf_conntrack_ecache Writers own nf_ct_ecache_mutex. Reported-by: Valdis Kletnieks <Valdis.Kletnieks@xxxxxx> Signed-off-by: Eric Dumazet <eric.dumazet@xxxxxxxxx> --- net/netfilter/nf_conntrack_ecache.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/net/netfilter/nf_conntrack_ecache.c b/net/netfilter/nf_conntrack_ecache.c index f516961..cdcc764 100644 --- a/net/netfilter/nf_conntrack_ecache.c +++ b/net/netfilter/nf_conntrack_ecache.c @@ -85,7 +85,8 @@ int nf_conntrack_register_notifier(struct nf_ct_event_notifier *new) struct nf_ct_event_notifier *notify; mutex_lock(&nf_ct_ecache_mutex); - notify = rcu_dereference(nf_conntrack_event_cb); + notify = rcu_dereference_protected(nf_conntrack_event_cb, + lockdep_is_held(&nf_ct_ecache_mutex)); if (notify != NULL) { ret = -EBUSY; goto out_unlock; @@ -105,7 +106,8 @@ void nf_conntrack_unregister_notifier(struct nf_ct_event_notifier *new) struct nf_ct_event_notifier *notify; mutex_lock(&nf_ct_ecache_mutex); - notify = rcu_dereference(nf_conntrack_event_cb); + notify = rcu_dereference_protected(nf_conntrack_event_cb, + lockdep_is_held(&nf_ct_ecache_mutex)); BUG_ON(notify != new); rcu_assign_pointer(nf_conntrack_event_cb, NULL); mutex_unlock(&nf_ct_ecache_mutex); @@ -118,7 +120,8 @@ int nf_ct_expect_register_notifier(struct nf_exp_event_notifier *new) struct nf_exp_event_notifier *notify; mutex_lock(&nf_ct_ecache_mutex); - notify = rcu_dereference(nf_expect_event_cb); + notify = rcu_dereference_protected(nf_expect_event_cb, + lockdep_is_held(&nf_ct_ecache_mutex)); if (notify != NULL) { ret = -EBUSY; goto out_unlock; @@ -138,7 +141,8 @@ void nf_ct_expect_unregister_notifier(struct nf_exp_event_notifier *new) struct nf_exp_event_notifier *notify; mutex_lock(&nf_ct_ecache_mutex); - notify = rcu_dereference(nf_expect_event_cb); + notify = rcu_dereference_protected(nf_expect_event_cb, + lockdep_is_held(&nf_ct_ecache_mutex)); BUG_ON(notify != new); rcu_assign_pointer(nf_expect_event_cb, NULL); mutex_unlock(&nf_ct_ecache_mutex); -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
