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[NETFILTER]: nf_conntrack: fix smp_processor_id() in preemptible code warning

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Since we're using RCU for the conntrack hash now, we need to avoid
getting preempted or interrupted by BHs while changing the stats.

Fixes warning reported by Tilman Schmidt <tilman@imap.cc> when using
preemptible RCU:

[   48.180297] BUG: using smp_processor_id() in preemptible [00000000] code: ntpdate/3562
[   48.180297] caller is __nf_conntrack_find+0x9b/0xeb [nf_conntrack]
[   48.180297] Pid: 3562, comm: ntpdate Not tainted 2.6.25-rc2-mm1-testing #1
[   48.180297]  [<c02015b9>] debug_smp_processor_id+0x99/0xb0
[   48.180297]  [<fac643a7>] __nf_conntrack_find+0x9b/0xeb [nf_conntrack]

Tested-by: Tilman Schmidt <tilman@imap.cc>
Tested-by: Christian Casteyde <casteyde.christian@free.fr> [Bugzilla #10097]

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Patrick McHardy 2008-02-27 12:07:47 -08:00 committed by David S. Miller
parent 3bdfe7ec08
commit 4e29e9ec7e
1 changed files with 12 additions and 3 deletions
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15
net/netfilter/nf_conntrack_core.c
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@ -256,13 +256,19 @@ __nf_conntrack_find(const struct nf_conntrack_tuple *tuple)
struct hlist_node *n;
unsigned int hash = hash_conntrack(tuple);
/* Disable BHs the entire time since we normally need to disable them
* at least once for the stats anyway.
*/
local_bh_disable();
hlist_for_each_entry_rcu(h, n, &nf_conntrack_hash[hash], hnode) {
if (nf_ct_tuple_equal(tuple, &h->tuple)) {
NF_CT_STAT_INC(found);
local_bh_enable();
return h;
}
NF_CT_STAT_INC(searched);
}
local_bh_enable();
return NULL;
}
@ -400,17 +406,20 @@ nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
struct hlist_node *n;
unsigned int hash = hash_conntrack(tuple);
rcu_read_lock();
/* Disable BHs the entire time since we need to disable them at
* least once for the stats anyway.
*/
rcu_read_lock_bh();
hlist_for_each_entry_rcu(h, n, &nf_conntrack_hash[hash], hnode) {
if (nf_ct_tuplehash_to_ctrack(h) != ignored_conntrack &&
nf_ct_tuple_equal(tuple, &h->tuple)) {
NF_CT_STAT_INC(found);
rcu_read_unlock();
rcu_read_unlock_bh();
return 1;
}
NF_CT_STAT_INC(searched);
}
rcu_read_unlock();
rcu_read_unlock_bh();
return 0;
}