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Diffstat (limited to 'net')
-rw-r--r--net/netfilter/nf_conntrack_core.c23
1 files changed, 22 insertions, 1 deletions
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index 9f530adad10d..4cbda4bd8926 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -83,6 +83,13 @@ void nf_conntrack_lock(spinlock_t *lock) __acquires(lock)
spin_lock(lock);
while (unlikely(nf_conntrack_locks_all)) {
spin_unlock(lock);
+
+ /*
+ * Order the 'nf_conntrack_locks_all' load vs. the
+ * spin_unlock_wait() loads below, to ensure
+ * that 'nf_conntrack_locks_all_lock' is indeed held:
+ */
+ smp_rmb(); /* spin_lock(&nf_conntrack_locks_all_lock) */
spin_unlock_wait(&nf_conntrack_locks_all_lock);
spin_lock(lock);
}
@@ -128,6 +135,14 @@ static void nf_conntrack_all_lock(void)
spin_lock(&nf_conntrack_locks_all_lock);
nf_conntrack_locks_all = true;
+ /*
+ * Order the above store of 'nf_conntrack_locks_all' against
+ * the spin_unlock_wait() loads below, such that if
+ * nf_conntrack_lock() observes 'nf_conntrack_locks_all'
+ * we must observe nf_conntrack_locks[] held:
+ */
+ smp_mb(); /* spin_lock(&nf_conntrack_locks_all_lock) */
+
for (i = 0; i < CONNTRACK_LOCKS; i++) {
spin_unlock_wait(&nf_conntrack_locks[i]);
}
@@ -135,7 +150,13 @@ static void nf_conntrack_all_lock(void)
static void nf_conntrack_all_unlock(void)
{
- nf_conntrack_locks_all = false;
+ /*
+ * All prior stores must be complete before we clear
+ * 'nf_conntrack_locks_all'. Otherwise nf_conntrack_lock()
+ * might observe the false value but not the entire
+ * critical section:
+ */
+ smp_store_release(&nf_conntrack_locks_all, false);
spin_unlock(&nf_conntrack_locks_all_lock);
}