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authorLiping Zhang <liping.zhang@spreadtrum.com>2016-07-23 22:16:56 +0800
committerPablo Neira Ayuso <pablo@netfilter.org>2016-08-08 09:26:40 +0200
commit707e6835f89419ff1c05e828c2d9939fd95a7ad8 (patch)
treefaaf3c1d830f7ad39dad6effc862aeec0ef49663 /net
parentc518189567eaf42b2ec50a4d982484c8e38799f8 (diff)
netfilter: nf_ct_h323: do not re-activate already expired timer
Commit 96d1327ac2e3 ("netfilter: h323: Use mod_timer instead of set_expect_timeout") just simplify the source codes if (!del_timer(&exp->timeout)) return 0; add_timer(&exp->timeout); to mod_timer(&exp->timeout, jiffies + info->timeout * HZ); This is not correct, and introduce a race codition: CPU0 CPU1 - timer expire process_rcf expectation_timed_out lock(exp_lock) - find_exp waiting exp_lock... re-activate timer!! waiting exp_lock... unlock(exp_lock) lock(exp_lock) - unlink expect - free(expect) - unlock(exp_lock) So when the timer expires again, we will access the memory that was already freed. Replace mod_timer with mod_timer_pending here to fix this problem. Fixes: 96d1327ac2e3 ("netfilter: h323: Use mod_timer instead of set_expect_timeout") Cc: Gao Feng <fgao@ikuai8.com> Signed-off-by: Liping Zhang <liping.zhang@spreadtrum.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net')
-rw-r--r--net/netfilter/nf_conntrack_h323_main.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/net/netfilter/nf_conntrack_h323_main.c b/net/netfilter/nf_conntrack_h323_main.c
index bb77a97961bf..5c0db5c64734 100644
--- a/net/netfilter/nf_conntrack_h323_main.c
+++ b/net/netfilter/nf_conntrack_h323_main.c
@@ -1473,7 +1473,8 @@ static int process_rcf(struct sk_buff *skb, struct nf_conn *ct,
"timeout to %u seconds for",
info->timeout);
nf_ct_dump_tuple(&exp->tuple);
- mod_timer(&exp->timeout, jiffies + info->timeout * HZ);
+ mod_timer_pending(&exp->timeout,
+ jiffies + info->timeout * HZ);
}
spin_unlock_bh(&nf_conntrack_expect_lock);
}