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| author | Patrick McHardy <kaber@trash.net> | 2010-05-10 19:45:56 +0400 |
|---|---|---|
| committer | Patrick McHardy <kaber@trash.net> | 2010-05-10 19:45:56 +0400 |
| commit | 3b254c54ec46eb022cb26ee6ab37fae23f5f7d6a (patch) | |
| tree | 3b71d7fe1f16ecb43d1fab6925307a4000da4315 | |
| parent | e772c349a11de448f194d0c9f2e7eb23800e1a13 (diff) | |
| download | linux-3b254c54ec46eb022cb26ee6ab37fae23f5f7d6a.tar.xz | |
netfilter: nf_conntrack_proto: fix warning with CONFIG_PROVE_RCU
===================================================
[ INFO: suspicious rcu_dereference_check() usage. ]
---------------------------------------------------
include/net/netfilter/nf_conntrack_l3proto.h:92 invoked rcu_dereference_check()
without protection!
other info that might help us debug this:
rcu_scheduler_active = 1, debug_locks = 0
2 locks held by iptables/3197:
#0: (sk_lock-AF_INET){+.+.+.}, at: [<ffffffff8149bd8c>]
ip_setsockopt+0x7c/0xa0
#1: (&xt[i].mutex){+.+.+.}, at: [<ffffffff8148a5fe>]
xt_find_table_lock+0x3e/0x110
stack backtrace:
Pid: 3197, comm: iptables Not tainted 2.6.34-rc4 #2
Call Trace:
[<ffffffff8105e2e8>] lockdep_rcu_dereference+0xb8/0xc0
[<ffffffff8147fb3b>] nf_ct_l3proto_module_put+0x6b/0x70
[<ffffffff8148d891>] state_mt_destroy+0x11/0x20
[<ffffffff814d3baf>] cleanup_match+0x2f/0x50
[<ffffffff814d3c63>] cleanup_entry+0x33/0x90
[<ffffffff814d5653>] ? __do_replace+0x1a3/0x210
[<ffffffff814d564c>] __do_replace+0x19c/0x210
[<ffffffff814d651a>] do_ipt_set_ctl+0x16a/0x1b0
[<ffffffff8147a610>] nf_sockopt+0x60/0xa0
...
The __nf_ct_l3proto_find() call doesn't actually need rcu read side
protection since the caller holds a reference to the protocol. Use
rcu_read_lock() anyways to avoid the warning.
Kernel bugzilla #15781: https://bugzilla.kernel.org/show_bug.cgi?id=15781
Reported-by: Christian Casteyde <casteyde.christian@free.fr>
Signed-off-by: Patrick McHardy <kaber@trash.net>
| -rw-r--r-- | net/netfilter/nf_conntrack_proto.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/net/netfilter/nf_conntrack_proto.c b/net/netfilter/nf_conntrack_proto.c index a6defc793601..5886ba1d52a0 100644 --- a/net/netfilter/nf_conntrack_proto.c +++ b/net/netfilter/nf_conntrack_proto.c @@ -117,9 +117,13 @@ void nf_ct_l3proto_module_put(unsigned short l3proto) { struct nf_conntrack_l3proto *p; - /* rcu_read_lock not necessary since the caller holds a reference */ + /* rcu_read_lock not necessary since the caller holds a reference, but + * taken anyways to avoid lockdep warnings in __nf_ct_l3proto_find() + */ + rcu_read_lock(); p = __nf_ct_l3proto_find(l3proto); module_put(p->me); + rcu_read_unlock(); } EXPORT_SYMBOL_GPL(nf_ct_l3proto_module_put); |