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Subject[PATCH 3/7][RFC] netfilter: qtaguid: initialize a local var to keep compiler happy.
Date
From: JP Abgrall <jpa@google.com>

There was a case that might have seemed like new_tag_stat was not
initialized and actually used.
Added comment explaining why it was impossible, and a BUG()
in case the logic gets changed.

Cc: netdev@vger.kernel.org
Cc: JP Abgrall <jpa@google.com>
Cc: Ashish Sharma <ashishsharma@google.com>
Cc: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>
Signed-off-by: JP Abgrall <jpa@google.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
net/netfilter/xt_qtaguid.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/net/netfilter/xt_qtaguid.c b/net/netfilter/xt_qtaguid.c
index 7c4ac46..214a990 100644
--- a/net/netfilter/xt_qtaguid.c
+++ b/net/netfilter/xt_qtaguid.c
@@ -1255,7 +1255,7 @@ static void if_tag_stat_update(const char *ifname, uid_t uid,
struct data_counters *uid_tag_counters;
struct sock_tag *sock_tag_entry;
struct iface_stat *iface_entry;
- struct tag_stat *new_tag_stat;
+ struct tag_stat *new_tag_stat = NULL;
MT_DEBUG("qtaguid: if_tag_stat_update(ifname=%s "
"uid=%u sk=%p dir=%d proto=%d bytes=%d)\n",
ifname, uid, sk, direction, proto, bytes);
@@ -1320,8 +1320,19 @@ static void if_tag_stat_update(const char *ifname, uid_t uid,
}

if (acct_tag) {
+ /* Create the child {acct_tag, uid_tag} and hook up parent. */
new_tag_stat = create_if_tag_stat(iface_entry, tag);
new_tag_stat->parent_counters = uid_tag_counters;
+ } else {
+ /*
+ * For new_tag_stat to be still NULL here would require:
+ * {0, uid_tag} exists
+ * and {acct_tag, uid_tag} doesn't exist
+ * AND acct_tag == 0.
+ * Impossible. This reassures us that new_tag_stat
+ * below will always be assigned.
+ */
+ BUG_ON(!new_tag_stat);
}
tag_stat_update(new_tag_stat, direction, proto, bytes);
spin_unlock_bh(&iface_entry->tag_stat_list_lock);
--
1.7.9.5


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